**FIRE Cirrus Intensive Field Observations - II:**

**Operations Plan**

**Prepared by the FIRE Project Office and the FIRE Cirrus Working**

**Group**

**MAY 1991**

CIRRUS II INTENSIVE FIELD OBSERVATIONS:

OPERATIONS PLAN

TABLE OF CONTENTS

1.0 BACKGROUND 1

2.0 INTRODUCTION 5

3.0 SCIENTIFIC OBJECTIVES AND STRATEGIES 7

3.1 Modeling Cirrus Cloud Development 9

> 3.2 Characterizing Development of Cirrus Clouds 11
>
> 3.2.1 Structure of Cirrus Cloud Fields 11
>
> 3.2.2 Origin and Maintenance of Mesoscale Cirrus Cloud Features 12
>
> 3.2.3 Vertical Motions at the Mesoscale and Convective Scale 12
>
> 3.2.4 Water Budget of the Upper Troposphere 13
>
> 3.2.5 Radiative Budget of Cirrus Cloud Layer and Its Environment 13
>
> 3.2.6 Microphysical Development of Cirrus Clouds 14
>
> 3.2.7 Turbulence and Convection Processes in Cirrus Clouds 14
>
> 3.3 Relating Cirrus Cloud Radiative and Physical Proper-ties 15
>
> 3.4 Capabilities and Limitations of Satellite Cirrus Cloud Retrievals
> 16
>
> 3.5 Radiative Impacts of Cirrus Clouds 18
>
> 3.5.1 Monitoring the Radiative Impact of Cirrus 18
>
> 3.5.2 Evaluating the Radiative Impact of Cirrus Using GCM\'s 19
>
> 3.5.3 Evaluating the Radiative Impact of Mid-Latitude Cirrus Using

Regional Mesoscale Models 19

3.6 Surface-Based Remote Sensing of Cirrus Clouds 20

4.0 CIRRUS INTENSIVE FIELD OBSERVATIONS (CIRRUS IFO-II) 25

4.1 Synopsis 25

4.2 Schedule and Location 27

> 4.3 Observations 30

4.3.1 Satellite Observations 30

4.3.1.1 Simultaneous Satellite/Aircraft/Surface Site Observations 32

4.3.2 Surface Radiation and Remote Sensing Observations 34

4.3.2.1 Active Sensing Sensors 35

4.3.2.1.1 Lidar Observations 36

4.3.2.1.2 Wind Profiler Observations 39

4.3.2.1.3 Vertical Motion Observations 42

4.3.2.2 Radiance and Radiative Flux Observations 42

4.3.2.3 Radiometer Calibration Guidelines 47

4.3.3 Aircraft Observations 51

4.3.3.1 Aircraft Platforms and Instrumentation 52

4.3.3.2 Aircraft Sampling Strategies 55

4.3.3.3 Aircraft Missions 63

4.3.4 Rawinsonde Observations 72

4.4 Operational Forecasting\.... 75

5.0 OPERATIONS 79

5.1 Functional Organization 79

5.2 Aircraft Integration and Unloading Sites 83

5.2.1 ER-2 83

5.2.2 King Air and Sabreliner 83

5.2.3 Citation 84

5.3 Logistics 84

5.3.1 Pre-Mission Site Inspection 84

5.3.2 Equipment Shipment 84

> 5.3.3 Personnel Deployment 85
>
> 5.3.4 Accommodations 85
>
> 5.4 Location of Instruments, Aircraft, and Mission Operations at
> Coffeyville

Airport 85

5.5 Communications and Data Transmission 85

5.6 Electronic Interference 91

5.7 Briefing, Planning, and Coordination Meetings 92

5.7.1 Mission Selection Team Meeting 92

5.7.2 Weather Briefing 92

5.7.3 Preflight Status Briefing 93

5.7.4 Mission Debriefing 93

5.7.5 Data Intercomparison Meetings 93

5.7.6 Nominal Schedule for Non-Flight Day 94

5.7.7 Nominal Schedule for Flight Day 94

5.8 Work Schedules . 94

5.9 Aircraft Access 94

5.10 Flight Personnel 96

5.11 Safety Procedures and Operations Requirements 96

5.11.1 Aircraft 96

5.11.2 Lidar 97

5.12 Flight Constraints 97

5.13 Flight Go/No Go 98

5.14 Mission Abort 99

5.15 Medical Considerations 99

5.15.1 General 99

5.15.2 Flight 100

> 5.16 Insurance Considerations 100
>
> 5.17 Public Relations 100
>
> 5.18 Aircraft and Site Tours 100
>
> 5.19 Operations Phase Out 101
>
> 5.19.1 Equipment Return 101
>
> 5.19.2 Post-Mission Calibration 101
>
> 5.19.3 Storage of Equipment 101

6.0 DATA MANAGEMENT 103

6.1 Data Products 104

6.2 Data Management Responsibilities 105

6.2.1 Principal Investigators 105

6.2.2 Working Groups 105

6.2.3 FIRE Data Management Working Group 105

6.2.4 FIRE Central Archive 105

6.2.5 FIRE Project Office 106

6.3 Standard Data Format 106

6.4 Data Schedule 106

6.4.1 Post-Mission Debrief 106

6.4.2 Post-Experiment Debrief 107

6.4.3 Preliminary Data Analysis Workshop 107

6.4.4 Final Reduced Data Submittal 107

6.4.5 FIRE Access to Data Archive 107

6.4.6 Review of Results/Science Planning Workshop 107

6.4.7 Open Access to Data Archive 108

6.5 Data Protocol and Publications Plan 108

7.0 SCHEDULES 109

7.1 1991 Cirrus IFO-II Major Milestones 109

7.2 Cirrus IFO-II Operations Schedule 111

7.3 PERT Chart for Cirrus IFO-II Project Management 112

8.0 REFERENCES 113

APPENDIX A - DESCRIPTION OF PLATFORMS, INSTRUMENTATION, AND

DATA PRODUCTS A-1

APPENDIX B - SATELLITE OVERPASS TIMES B-1

APPENDIX C - FIRE PARTICIPANTS C-1

APPENDIX D - STANDARD DATA FORMAT D-1

APPENDIX E - GENERAL INFORMATION ON COFFEYVILLE, KANSAS E-1

APPENDIX F - ACRONYMS F-I

APPENDIX G - COLLABORATIVE EXPERIMENTS G-1

APPENDIX H - LISTING OF NWS STATIONS AND CODES H-1

1.0 BACKGROUND

FIRE (First ISCCP Regional Experiment) is an ongoing multi-agency
program designed to promote the development of improved cloud and
radiation parameterizations for use in climate models, and to provide
for assessment and improvement of International Satellite Cloud
Climatology Program (ISCCP) products. FIRE enjoys support from the
National Aeronautics and Space Administration (NASA), the National
Science Foundation (NSF), the Office of Naval Research (ONR), the
Department of Energy (DOE), the National Oceanic and Atmospheric
Administration (NOAA), the United States Air Force (USAF), the Air Force
Geophysical Laboratories (AFGL) Office of Scientific Research, and other
elements of the Department of Defense (DOD). Although FIRE is
principally a United States national project, it benefits from important
contributions by scientists from the United Kingdom and France.

The strategy of FIRE has been to combine modeling activities with
satellite, airborne, and surface observations to study two types of
climatically important cloud systems\--cirrus and marine
stratocumulus\--that have important roles in the climate system by
virtue of their extensive areal coverage, persistence, and radiative
effects. Cirrus and marine stratocumulus clouds may be quite sensitive
to changes in the climate system with the capability to significantly
interact with and modulate those changes (feedback). The FIRE strategy
consists of three principal thrusts:

*• A modeling program that encompasses general circulation models
(GCM's), process models mesoscale models, and radiative transfer
models;*

*• a cirrus observing program, that conducted a field campaign in 1986
and plans a follow-on campaign for late 1991; and*

*• a marine boundary-layer cloud observing program that conducted a
field campaign in 1987 and plans a follow-on campaign (ASTEX - Atlantic
Stratocumulus Transition Experiment) in the summer of 1992.*

From its inception, FIRE has been designed to be conducted in two
phases. FIRE Phase I (1984-1989) was designed to address fundamental
questions concerning the maintenance of cirrus and marine stratocumulus
cloud systems (Bretherton et al., 1983; FIRE Implementation Plan, 1985).
FIRE research over those years has already led to major improvements in
our understanding of the role of these clouds in the global climate
system. FIRE has documented the strong influence of clouds on climate
and how these effects are produced. Perhaps more importantly, FIRE
investigations have enabled us to ask the right questions for the next
phase of productive research. Based on the results of Phase I, including
lessons learned in conducting intensive field programs, FIRE Phase II
(1989-1994) will focus on more detailed questions

concerning the formation, maintenance, and dissipation of these cloud
systems. Specifically, the scientific objectives of FIRE Phase II, as
outlined in the FIRE Phase II Research Plan (1989), are to:

*• Expand our basic knowledge of how clouds and cloud systems interact
with their* *environment and the climate;*

*• Identify, quantify, and simulate the processes instrumental in the
evolution of large-scale* *cloud systems;*

*• Quantify the capabilities of current models for simulating
large-scale cloud systems and* *the radiative properties of these
systems, and improve cloud physics and radiation* *parameterizations
used in general circulation models;*

*• Assess and improve the reliability of currently used cloud/radiation
monitoring systems* *from space and from the ground; and*

*• Assess the capability of future cloud/radiation monitoring systems,
such as the Earth* *Observing System (EOS).*

The first key component of FIRE Phase II is a study of the interaction
of large-scale cloud systems with the radiation field and with the
dynamic motion of the atmosphere, utilizing the observations of FIRE
Phase I and Phase II in conjunction with multi-scale modeling
investigations.

The second key component is the cirrus observational program (FIRE Phase
II: Cirrus Implementation Plan, 1990) that is scheduled for late fall
1991 in the lower Midwestern U.S. A central question around which this
field program is designed is:

***Are the cirrus cloud systems found in association with the
polar/midlatitude and* *subtropical jet streams similar with respect to
physical properties and evolution?***

Several specific questions which will be addressed using combined
observational and modeling approaches are:

• What is the role of large-scale, mesoscale, and small-scale
circulations in the evolution of midlatitude cirrus cloud systems?

• Do the radiative and microphysical properties of cirrus clouds differ
between subtropical and polar/midlatitude jet stream systems?

• What roles do small ice particles and ice crystal morphology play in
determining the radiative properties of cirrus?

• Are currently used cirrus cloud models capable of rendering realistic
life-cycle simulations of cirrus cloud systems?

• What are the ranges of natural variability in the upper tropospheric
water budget components (water, vapor, and ice) within and surrounding
cirrus cloud systems?

In recognition of the true multi-scale control of cirrus cloud systems,
the Cirrus Intensive Field Observations (IFO) - II will consist of a set
of nested observations/platforms. The large scale environment will be
defined from National Weather Service (NWS) rawinsonde data extending
from the west coast of the U.S. to the Appalachian mountains
complemented by NWS \"ridded data and products and satellite data. The
regional environs in the vicinity of the experiment will be monitored by
special rawinsonde stations, the NWS wind profiler network, and
satellites. The smaller scale will be intensely observed using special
wind profiler installations, sophisticated surface-based lidar, radar
and radiometry, and remote and *in situ* sensing from aircraft. Active
participation by mesoscale models will provide, for the first time, a
methodology to investigate the links between the large-scale environment
and the small-scale measurements.

The third key component of FIRE Phase lI is the major field experiment
that is planned for the summer of 1992 in the eastern North Atlantic.
The ASTEX observational program will be conducted in June 1992 from a
base in the Azores and will consist of aircraft, island-based,
ship-based, buoy, and satellite platforms (FIRE Phase II: ASTEX
Implementation Plan, 1990). This field program has been designed to
address a number of scientific questions that revolve around the
following central, very complex question:

***What are the consequences for the atmosphere and ocean of the
prevalent boundary layer cloud type and amount, and how are the cloud
type and amount selected?***

Several physical mechanisms have been proposed to account for the
observed variations of marine boundary layer cloud type and amount.
These include:

• Cloud top entrainment instability,

• Diurnal decoupling of the cloud layer from the boundary layer and
subsequent cloud break-up due to solar warming and entrainment drying,

• Patchy drizzle leading to a similar decoupling scenario,

• Mesoscale circulations, and

• Episodic strong subsidence lowering the inversion below the lifting
condensation level (LCL).

Each of these mechanisms has been investigated in a variety of
already-published studies, but we currently lack the data to put the
various ideas to the test.

A major goal of ASTEX is to provide data that can be used to drive and
validate climate models. A key strategy is the measurement of the
budgets of mass, thermodynamic energy, and moisture within an Eulerian
\'grid column\' located in the ASTEX observing region. Some of these
observations are needed as inputs to climate model codes; good examples
are the large-scale pressure gradient force, the large-scale vertical
motion field, and the tendencies of temperature and moisture due to
horizontal advection. A single-column version of a climate model can be
used to simulate observed ASTEX cases, provided that such external
forcings, which no single-column model can determine, are provided as
input.. Obviously, additional ASTEX observations can be compared
directly with results produced by a single-column climate model;
examples are the cloudiness, the convective and radiative fluxes, and
the vertical profiles of temperature and water vapor. In some cases,
such observations can be used to test, decisively, the physical
assumptions underlying the parameterizations used in a climate model.
For example, models typically parameterize the entrainment rate in terms
of the convective flux profiles; ASTEX will provide observations of both
the flux profiles and the entrainment rate, allowing direct tests of
such closure assumptions.

Lastly, an Extended Time Observations (ETO) activity will consist of
coordinated satellite observations, meteorological analyses, and data
from a limited number of special ground sites with lidar and/or
radiation measurements throughout the year. These data will provide a
means of extending the results derived in the more detailed IFO
intercomparison studies to larger time and space scales. The ETO program
will directly support the ISCCP and GCM validation efforts.

2.0 INTRODUCTION

The cirrus observational program is a key component of FIRE Phase II
research (FIRE Phase II: Cirrus Implementation Plan, 1990). The
principal element is the Cirrus Intensive Field Observations (IFO) - II
which will be conducted November 13-December 7, 1991, in southeastern
Kansas. The Cirrus IFO-II will combine coordinated satellite, airborne,
and surface observations with modeling studies to investigate the cloud
properties and physical processes of mid-continent cirrus clouds and
cirrus clouds associated with the sub-tropical jet stream.

The Cirrus IFO-II program will support research requiring high time and
space resolution measurements of cirrus cloud systems. The data will be
analyzed to improve quantitative understanding of the processes
responsible for the formation and maintenance of extended cirrus cloud
systems in the middle latitudes. Emphasis will be focused on the roles
and interactions of processes acting on scales ranging from the
microscale to the synoptic scale, and on characterizing the physical
properties of these clouds. These data will also be instrumental in
developing parameterizations relating cloud-scale processes to
climate-scale variables, and in better understanding the ISCCP data
products. Lastly, these data will be used to improve the ability to
utilize and interpret remote sensing observations for characterizing the
properties of cirrus clouds, especially satellite-based radiometric
observations for descriptions of global cloudiness (e.g., ISCCP), and
including surface and airborne lidar, radar, and passive radiometric
observations. The intensive field observations will be gathered from a
variety of platforms on a relatively local, but regionally
representative, geographical scale. Data will be collected from multiple
satellites, aircraft, balloon, and surface-based instrumentation.

The Cirrus IFO-II is a second generation regional experiment: the first
Cirrus IFO-I, was conducted in October 1986 in central Wisconsin to
study mid-continent cirrus cloud systems. The planned use of two phases
for the intensive field program is important. In 1984, relatively little
was known about cirrus cloud systems since no major experiments had been
previously performed. Consequently, research on cirrus clouds had been
stifled because of the lack of observational data. The two-phase field
program, with 5 years in between, has been designed to enable
experimenters to incorporate information gained and lessons learned from
the first phase into the second phase of the experiment. This is
especially important when investigating a phenomenon about which
relatively little is quantitatively known from either an observational
or a theoretical viewpoint.

This Operations Plan will fully describe the field experiment, including
scientific objectives, participating platforms and instruments,
experiment methodology, expected data products, experiment logistics,
data management, and schedules. Additional copies of this document are
available from:

David S. McDougal

FIRE Project Manager

Mail Stop 483.

NASA Langley Research Center

Hampton, VA 23665-5225

3.0 SCIENTIFIC OBJECTIVES AND STRATEGIES

> The key FIRE Phase II cirrus science objectives are to:
>
> 1\) Incorporate FIRE Phase I data and Phase II data into models of
> varying scale and complexity for the purpose of developing and testing
> cirrus parameterizations and assessing capabilities to reliably
> simulate cirrus development on short and long time scales.
>
> 2\) Characterize the physical, thermodynamical, and dynamical
> development of cirrus clouds on
>
> • the synoptic scale,
>
> • the mesoscale,
>
> • the convective/turbulent scale, and
>
> • the microscale.
>
> 3\) Characterize relationships among various cirrus cloud optical
> properties, including,
>
> • cloud optical depths in the visible, near infrared, and infrared,
>
> • cloud scattering phase functions, and
>
> • cloud single-scattering albedos;
>
> and the corresponding cloud physical properties, including,
>
> • particle size, number density, phase, and habit, and
>
> • cloud height, temperature, and thickness.
>
> 4\) Explicitly quantify the capabilities and limitations of methods to
> derive physical and optical cirrus cloud properties from satellite
> observations, especially ISCCP, and future techniques for producing
> global cloud climatologies in the EOS era.
>
> 5\) Quantify the impact of cirrus clouds on the surface, atmosphere,
> and top-of- atmosphere radiation budgets.
>
> 6\) Improve the capability to utilize surface-based active and passive
> remote sensing observations for quantitative studies of cirrus clouds.
>
> The rationale and strategy for achieving each of these objectives are
> described as follows.

3.1 Modeling Cirrus Cloud Development

Numerical modeling is a fundamental component of FIRE research of the
physics and dynamics of cirrus clouds and the impact of cirrus on the
global climate. Greater reliability and credibility of GCM-based
predictions of climate change requires development of physically based
cirrus cloud parameterizations that have been experimentally verified.
Because GCM\'s diagnose the ice and liquid water contents, cloud heights
and amounts, and cloud radiative properties of cirrus from the resolved
large-scale fields, each of these must be measured as accurately as
possible and with as much temporal resolution as possible in
constructing suitable verification data sets for testing cirrus cloud
parameterizations.

Many processes acting to determine the physical properties and
distribution of cirrus clouds operate on scales smaller than those
resolved in GCM\'s. Extended cirrus systems are typically organized into
distinct mesoscale regions of enhanced cloudiness which are often
comprised of numerous small-scale convective-appearing cellular
structures. The small-scale circulations strongly influence the
microphysical development of the cloud (Starr and Cox, 1985b). The
resultant sizes and habits of the constituent cloud particles determine,
to a large extent, the net downward vertical flux of cloud water via
gravitational settling. In turn, it is the balance between the rates of
ice water generation and depletion, primarily via ice particle fallout,
that determines the overall cloud water content and radiative properties
as well as the vertical development of the cloud layer and feedback to
the larger scale (Starr, 1987a). Clearly, development of a
physically-based GCM cirrus cloud parameterization requires knowledge of
these processes.

Consequently, FIRE cirrus research includes a strong effort to model
cirrus cloud development on smaller scales. Models are used to
investigate the basic physics and dynamics governing cirrus cloud
formation, evolution, and structure. These include regional mesoscale
models which are either self-contained inside of a limited domain or are
nested within larger scale models, very high resolution mesoscale cloud
models, and models of fundamental turbulence interactions and
microphysical growth. In Phase II, these models will incorporate the
high resolution data sets to assist in the formulation and testing of
cirrus parameterization schemes.

The credibility of these models must also be established. This requires
that suitable initialization and verification data sets must be
obtained. Accurate measurements of thermodynamic and dynamic conditions
at the appropriate time and space scales, in conjunction with
appropriately detailed and quantitative physical descriptions of the
corresponding clouds , are essential. In particular, accurate
descriptions of vertical motions, the water vapor budgets for the vapor,
liquid, and ice phases, cloud structure, and cloud composition
(especially the populations of small particles) are essential if the
uncertainties are to be reduced to an acceptable level. The data sets
must adequately resolve the fundamental scales at which the physical
processes are organized. Observations of the aerosol particles involved
in the nucleation process and of the characteristics of turbulence are
also needed.

There is also a need to assess the predictability of cirrus clouds on
large and small scales. High quality data sets of cirrus cloud structure
and evolution along with simultaneous measurements of the large-scale
fields must be obtained.

Forecast experiments with both mesoscale and global-scale models will be
used to test current and new cirrus parameterization schemes and to
examine the predictability of cirrus. Specific models that will be used
include the Colorado State University/Regional Atmospheric Model
(CSU/RAMS), Pennsylvania State University/National Center for
Atmospheric Research (PSU/NCAR), and National Meteorological Center
(NMC) eta mesoscale models and possibly the United Kingdom
Meteorological Office (UKMO) global model. Experiments using nested
grids will be performed with the mesoscale models and will draw heavily
from the highly detailed process models. Large-scale data sets with
increased temporal resolution over a wide area are required for improved
definition of the development of the dynamic and thermodynamic
environment of extended cirrus cloud systems, especially the
distribution of upper tropospheric water vapor. This is particularly
true for the mesoscale models that serve as the bridge between the very
detailed models and the global-scale models and provide the framework
for investigating scale interactions that are central to the problem of
relating cloud response and feedback to large-scale control.

The strategy for obtaining the data sets required for initializing
numerical models and verifying models results over a range of scales,
developing and testing parameterizations of cirrus clouds, and
evaluating the predictability of cirrus is to:

> • Obtain data sets with improved resolution of the large-scale fields
>
> 1\) by enhancing the frequency of rawinsonde launches over a wide
> area,
>
> 2\) by enhancing the horizontal resolution of rawinsonde data over a
> mesoscale region through he addition of several special stations, and
>
> 3\) by including new nearly continuous wind data from a mesoscale
> network of NWS wind profilers over this same region.
>
> • incorporate the above data into a Four Dimensional Data Assimilation
> (FDDA) using regional mesoscale models to produce dynamically
> consistent \"ridded analyses on the time and space scales required for
> testing parameterizations. This approach makes optimal use of data
> obtained from irregularly spaced and asynchronous observing systems.
>
> The NOAA Forecast Systems Laboratories (FSL) Program for Regional
> Observing and Forecasting Services (PROFS) has developed and continues
> to improve a Mesoscale Analysis and Prediction System (MAPS) that is
> used for regional data assimilation over the continental U.S. on an
> operational basis. MAPS presently employs a 3-hour assimilation (data)
> cycle on an 80-km horizontal grid with 18 vertical levels in a hybrid
> isentropic coordinate system (Benjamin et al., 1991). The new
> Eta-model under development by the National Meteorological Center will
> also employ a 3-hour data cycle but plans for a 30-km grid with 30
> levels in the vertical (the Eta model will be in operational testing
> during Fall 1991). Both systems are designed to access the operational
> data stream including Automation of Field Operations and Services
> (AFOS) (rawinsondes and surface observations), AIRINC Communications,
> Addressing, and Reporting System (ACARS) (commercial aircraft), and
> the new NWS profiler data (via the Profiler Hub at FSL). The systems
> are well-suited to FIRE\'s needs in terms of data cycle interval and
> mesoscale resolution. Thus, to the extent possible or practical , the
> relevant FIRE observations (supplementary rawinsondes and profiler
> observations) should be placed in the appropriate operational data
> streams for inclusion in these analyses that will serve as a basis for
> a variety of mesoscale model testing activities and experimentation in
> FIRE Cirrus-II.
>
> Obtain quantitative physical descriptions of the cirrus cloud fields.
> *These data sets must be as complete and accurate as possible at each
> scale.* For the [wide area]{.underline}, the required descriptions
> will be derived from satellite observations and include
> time-dependent, horizontal distributions of:
>
> -top-of-atmosphere radiative fluxes,
>
> -cloud heights and amounts,
>
> -cloud radiative properties (broadband infrared emittance and
> shortwave albedo).
>
> Over the [core mesoscale observing area]{.underline}, the descriptions
> should additionally include time-dependent, vertical, and horizontal
> distributions of:
>
> -cloud ice and liquid water contents,
>
> -and cloud particle number density size distributions and habits.
>
> In addition, the following [mesoscale]{.underline} measurements are
> highly desired:
>
> \- upper tropospheric water vapor content,
>
> \- numbers, types, and composition of ice nuclei, and cloud
> condensation nuclei, and - dynamic structure (convective/turbulence)
> within cirrus clouds.

At this latter scale, the descriptions will be derived from in situ
(aircraft and sondes) and remote sensing (satellite, airborne and
ground-based) observations. The integration of these observations into a
coherent description is a formidable task (section 3.2).

3.2 Characterizing Development of Cirrus Clouds

Production of data sets suitable for initialization and verification of
cirrus cloud development models requires careful analysis and
integration of diverse observations. The data requirements are briefly
described as follows.

3.2.1 Structure of Cirrus Cloud Fields

Quantitative descriptions of the time-dependent, horizontal, and
vertical structure of the observed cirrus cloud fields are required.
These descriptions must include accurate distributions of cloud height,
areal coverage, and cloud radiative properties over a large region
encompassing the domain of regional mesoscale models. Additional
parameters such as cloud thickness and the bulk cloud microphysical
properties (vertically integrated ice water content and mean particle
size) are highly desirable. Characterization of the vertical
distribution of cloud parameters is also desirable (e.g., delineating
multilayered structure). Satellite-based observations provide the only
means to produce such regional analyses. However, achievement of the
level of detail and accuracy needed to meaningfully constrain regional
mesoscale models requires significant improvements in current algorithms
used to process satellite data. Such improvements will only result from
detailed comparisons of satellite observations with quantitative
\'ground truth\' descriptions derived from surface-based (remote
sensing) and airborne (remote sensing and *in situ*) observations.

To be useful for application to cloud process models, the cloud physical
descriptions required for meaningful comparison to model simulations
must be correspondingly more detailed. The time-dependent, vertical
structure of cloud water content, particle size distribution, particle
shape distribution, and particle phase are needed over a relatively
small mesoscale region (\~20 -50 km). Both Eulerian and Lagrangian
descriptions are highly valuable. In addition, the structure of these
fields must be characterized in terms of the magnitude and spatial
scales of variability, including that of the cloud radiative properties.
Although *in situ* observations (aircraft) can provide the basic
required microphysical and radiative measurements, the sampling
limitations of aircraft platforms do result in uncertainties associated
with spatial coverage and representativeness. Integration of those
observations with satellite, airborne, and surface-based remote sensing
observations can potentially provide a significantly more complete
characterization.

3.2.2 Origin and Maintenance of Mesoscale Cirrus Cloud Features

Extended cirrus cloud systems exhibit a significant degree of persistent
mesoscale organization. This may reflect corresponding structure in the
ambient dynamic and thermodynamic fields (Starr and Wylie, 1990). In
order to understand the origin and maintenance of mesoscale cirrus cloud
features, the time-dependent structure of the cloud fields (section
3.2.1 ) must be known in conjunction with the corresponding dynamical
and thermodynamical fields. Given that high wind speeds are typical at
cirrus altitude, significant enhancements to the routine synoptic upper
air observing schedules will be required to resolve these fast moving
and relatively small-scale dynamical features. Fortunately, a new
capability exists to actually resolve upper tropospheric wind fields on
a near-continuous basis (\~6 min values) at a relatively fine scale
(\~200 km) using the NOAA/NWS wind profiler network that is presently
under construction. Acquisition of thermodynamic information at
increased frequency (supplemental rawinsondes) will facilitate analysis
of these mesoscale features.

3.2.3 Vertical Motions at the Mesoscale and Convective Scale

Observations of vertical motions in cirrus clouds have always been very
problematic and have significantly retarded progress in quantitatively
testing cloud development models since model simulations are very
sensitive to the prescribed large-scale forcing. In particular, accurate
knowledge of vertical motions on the scale of individual mesoscale cloud
features (20 - 100 km) is essential. The required approach is to apply
every available means for characterizing vertical motions in cirrus
clouds.

Data from a mesoscale network of wind profilers would enable calculation
of the upper tropospheric vertical motion field at the required space
and time scales using kinematic techniques (derived from divergence
analysis of observed horizontal winds). Similar techniques can also be
applied to scanning Doppler lidar (CO2 and Doppler radar (mm)
observations and to aircraft-observed horizontal wind profiles (Gultepe
et al., 1990) to generate profiles of vertical velocity at a scale of
about 20 km. Kinematic and adiabatic techniques can be used for deriving
vertical motions from rawinsonde observations at a larger scale (Starr
and Wylie, 1990). Vertical motion fields are also derived from FDDA
(section 3. 1).

Conventional in situ measurements from aircraft (inertial and gust
probe) provide a means to characterize convective scale (\~ 1 km)
motions which are needed for initialization of microphysical models and
verification of high-resolution mesoscale cloud models. Alternate
strategies and methods should be utilized to the extent possible in
order to provide the broadest possible observational basis. For example,
direct inference based on Doppler velocity spectra obtained using
CO2-lidar or millimeter radar (Eberhard et al., 1990; Kropfli et al.,
1990) or wind profiler measurements taken in a vertically-pointing
configuration is possible. Such capabilities are highly desirable. In
addition, radar tracking of chaff released in a cloud and in situ
sampling and analysis of inert chemical tracers, such as sulfur
hexafluoride, can be used to assess transports within a cloud. Each of
these techniques will be tried.

3.2.4 Water Budget of the Upper Troposphere

A key factor influencing cirrus cloud development and also manifesting
the effects of cloud processes is the distribution and redistribution,
respectively, of the upper tropospheric water budget components (liquid,
vapor, and ice). The limitations of rawinsonde moisture transducers in
the cold upper tropospheric environment are well documented. The
combined time lag and temperature sensitivity liabilities make
rawinsonde upper tropospheric humidity observations reliable only as a
semi-quantitative indicator of moisture. While imagery from the
Geostationary Operational Environmental Satellite (GOES) 6.7 micron
water vapor channel has long been very useful to forecasters, it has
proven very difficult to quantify the vertical profile of water vapor
since the detected signal is strongly coupled to atmospheric temperature
structure and the vertical distribution of water vapor (Blackwell, et
al., 1988). Similarly, information on tropospheric water vapor derived
from the three High-Resolution Infrared Sounder (HIRS) water vapor
channels on the operational NOAA polar orbiting satellites has also seen
little use in operational forecast models. Recent advances in aircraft
instrumentation (cryogenic frost-point hygrometer) now provide the means
to accurately observe atmospheric water vapor contents at cold
temperatures. Raman lidar has been used to remotely sense water vapor
contents to altitudes of 6 km at night (Melfi et al., 1989). On-going
improvements (a more powerful ultraviolet laser and more sensitive
detectors) promise to extend the useful Raman lidar operating range into
the upper troposphere at night and permit daylight observations. These
technologies should be utilized to the fullest extent possible to
provide the required observations. In addition, the possibility of using
these new observations to improve our ability to quantify the satellite
observations should be fully explored.

Characterizing the effects of cirrus cloud latent heating and cooling
and the rate of water vapor incorporation into cirrus clouds provides an
essential constraint on model-based studies and our understanding of
cirrus cloud development. Knowledge of the upper tropospheric water
vapor budget is a key ingredient in this methodology.

3.2.5 Radiative Budget of Cirrus Cloud Layer and Its Environment

Radiative processes significantly affect the development of cirrus
clouds. The pre-cirrus environment and the regions adjacent to cirrus
clouds may be moisture rich and thus experience radiative forcing which
may impact further cirrus evolution either by diabetic cooling or meso
and synoptic scale circulations. Once the cirrus cloud has formed,
further effects on its evolution by radiative forcing include
microphysical growth, static stability, and meso and synoptic scale
circulations. An accurate characterization of the radiative energy
budget (heating) of cirrus clouds is essential both for development and
verification of suitable parameterizations and models. It is important
that broadband radiative properties be resolved in a consistent manner
for the longwave (especially the 8-12 um region), and shortwave spectral
regions.

For the application here, a statistical approach is desired in which the
mean and variance of the observed radiative fluxes (rather than
radiances), cloud water content, and size distribution can be used to
derive representative bulk relationships enabling reproduction of the
gross features of the observed cloud radiative budget. Such
relationships can then be incorporated into detailed cloud models to
simulate the structure of radiative forcing in cirrus clouds.

3.2.6 Microphysical Development of Cirrus Clouds

The microphysical composition of the clouds is the dominant factor
determining the cloud radiative properties. Cirrus clouds are
microphysically complex consisting of a broad range of particle sizes
and particle habits (e.g., Heymsfield et al., 1990). In addition, the
water and energy transports associated with the gravitational settling
of larger crystals is a dominant factor regulating overall cloud
properties and exchanges with surrounding air.

Observations of the ambient cloud condensation nuclei (CCN) and ice
nuclei concentrations and compositions in conjunction with detailed
observations of the entire ice crystal populations are essential for
resolving these issues. Such observations should attempt to define these
parameters on the scale required for microphysical growth models,
usually that of an individual convective updraft (\~1 km). In addition
to optical probes and collection devices on aircraft, balloon-borne ice
crystal replication sondes provide an additional means to sample ice
crystal populations and ice water contents.

3.2.7 Turbulence and Convection Processes in Cirrus Clouds

Turbulent heat and moisture fluxes play an important role in the
evolution of cloud layers. Knowledge of the characteristic scales and
intensity of these processes would provide another constraint on the
performance of cloud development models and cirrus cloud
parameterizations. Although measurement of turbulence and turbulent
fluxes at cirrus (or any) altitude is very difficult, the potential
applicability of these data warrants the effort. Even relatively simple
information on the characteristic scales of cloud organization and scale
dependence of variance of dynamic and thermodynamic parameters would be
quite useful.

Analysis of turbulence characteristics typically employ spectral
techniques. These analyses require high‑frequency sampling (20 Hz) using
aircraft platforms. Adequate sample length is also required for
meaningful results (flight legs more than six times the length of the
analyzed scale). In addition, characterization of turbulence intensities
using remote observations (e.g., wind profilers) may be possible and
should be exploited.

3.3 Relating Cirrus Cloud Radiative and Physical Properties

Characterizing relationships between cirrus cloud radiative properties
in various spectral regions and cloud microphysical properties supports
each of the other key science objectives. These radiative effects
represent the most important impact of the clouds on the simulated
climate. To first order, it is the cloud radiative properties that are
the primary desired output of a GCM cirrus cloud parameterization.
However, cloud radiative properties are determined by cloud physical
properties which are, in turn, affected by radiative processes.
Conversely, monitoring of cirrus cloudiness and its radiative impact on
the surface and atmospheric energy budgets, whether from space or from
the earth\'s surface, requires that the detected radiances be
interpreted in terms of more useful quantitative measures of cloud
physical properties. This is particularly important given the general
lack of opacity and great natural variability of cirrus radiative and
physical properties in space and time.

The radiative properties of cirrus clouds critically depend on two
poorly known fundamental properties: the effective radiative particle
size and scattering phase function of the particle population. Both
depend on the sizes, shapes, orientations and, possibly, the composition
of the particles.

Relationships between the radiative and physical properties of cirrus
clouds can only be determined if adequate observations of the incident
and emergent radiative fields are available in conjunction with
coincident measurements of cloud composition. Improvements in our
ability to observe the microphysical composition of cirrus clouds,
especially the numbers of small particles, and enhancements in our
ability to resolve the associated radiative fields, including the
possibility of direct measurements of scattering phase functions, will
yield significant improvements in our knowledge of and ability to model
fundamental relationships between cirrus cloud optical properties and
microphysical properties.

The corresponding data requirements for relating the cirrus cloud
radiative and physical properties are:

> • Accurate measurements of the upwelling and downwelling radiance
> fields, including
>
> \- observations at visible, near infrared, and infrared wavelengths,
> and
>
> \- observations from various viewing angles, especially of reflected
> solar radiation.
>
> • Measurements of the cirrus cloud microphysical composition,
> including vertical distributions of
>
> \- particle number density size distribution to minimum of 10 µm,
>
> \- and particle phase, habits, and morphology.
>
> • Observations of the vertical distribution of cloud optical depth and
> temperature.
>
> • Direct measurement of ice crystal scattering phase functions and
> single‑scattering albedos, if possible.

Obtaining these data requires *in situ* observations from aircraft and
balloon‑borne ice particle replicators to define the microphysical
composition (and possibly the scattering phase function) and remote
observations from satellite, aircraft, and ground‑based sensors to
define the radiative fields and cloud optical depths.

Three key observational requirements are that:

> 1 ) the measurements be as coincident as operationally feasible,
>
> 2 ) some data sets be obtained over a water background to reduce the
> effects of surface reflectance, and
>
> 3\) the radiance observations be as accurate as possible.

This last requirement necessitates a concentrated effort to calibrate
and intercompare all radiometric sensors. To the extent possible, all
instruments should be referenced to a common standard.

This diverse set of observations will be incorporated into a hierarchy
of radiative transfer models as initial conditions and verification data
sets. Self‑consistent relationships between the microphysical and
radiative properties of cirrus can then be derived.

3.4 Capabilities and Limitations of Satellite Cirrus Cloud Retrievals

Satellite observations provide a means to quantify global cloudiness on
a climatological basis. Satellite observations permit monitoring of the
physical and radiative properties of cirrus clouds over extended time on
a global basis enabling resolution of changes in an *internal* component
of the climate system that will potentially play an important role in
modulating any global climate change. Moreover, the credibility of
models of the global climate system will be significantly enhanced if
the realism of crucial internal components, such as the treatment of
cirrus clouds, can be verified against suitable observations of the
present climate.

Inference of cloud physical properties from satellite‑observed radiances
requires assumptions about cloud structure and composition. In essence,
a radiative‑physical cirrus cloud model is invoked in any retrieval
procedure in order to make the desired inference. An objective of FIRE
is to *test the underlying a*ssumptions in these models. It is only
through a rigorous examination of the validity and representativeness of
these assumptions and models that improvements in satellite‑based cloud
observation capabilities will result.

Model assumptions of particular concern include:

> • the relationship between visible reflectance and infrared emittance,
>
> • the detection thresholds in terms of visible and infrared cloud
> optical depths,
>
> • the bi‑directional reflectance/scattering phase function models for
> cirrus, and
>
> • the effects of non‑spherical particle shapes on the radiative
> properties of clouds.

Additional aspects that need to be well‑understood are the effects of:

> • inhomogeneous cloud structure in the horizontal and vertical, and
>
> • situations of multiple cloud layers, particularly cirrus overlying
> altostratus or stratus.

Explicit quantitative knowledge of the capabilities and limitations of
present methodologies will enhance the value of the derived cloud
observations by providing a measure of the applicability of and
confidence in the cloud data.

Optimally, the cirrus cloud properties that are desired from present and
future methodologies and that will be considered in FIRE include:

> • cloud height, thickness, and amount,
>
> • cloud optical depth in the visible, near infrared, and infrared
> spectral regions,
>
> • cloud composition in terms of particle size and phase, and
>
> • vertically integrated cloud liquid water or ice content.

The data requirements to support the required investigations are nearly
identical to those given in section 3. 3. The key elements are for high
spatial resolution, multispectral observations at multiple viewing
angles in conjunction with coincident observations of cloud composition
and fundamental radiative properties as well as thermodynamic structure.
These data can only be obtained by simultaneous measurements using
satellite, aircraft, and surface‑based instruments. Accuracy and
representativeness are essential. Cross‑calibration of all radiometric
sensors is critical (satellites, aircraft and surface). In addition, a
high resolution, quantitative, satellite independent characterization of
the horizontal and vertical structure of the cloud fields over an area
larger than the resolution of operational satellite sensors (\~30 km for
sounding channels) is needed. Scanning cloud lidar or radar provide this
capability.

Some data sets must be acquired over a water background to provide
suitable simplest cases for treating cloud reflectances. In addition,
data sets corresponding to land surfaces, to nighttime conditions (a
cold background), and to snow‑covered backgrounds should also be
obtained to provide a means to evaluate and contrast model performance
in more demanding situations.

3.5 Radiative Impacts of Cirrus Clouds

The importance of cirrus clouds in modulating the radiative energy
budget of the earth\'s surface and atmosphere is a prime motivation for
FIRE cirrus research. FIRE research directed at quantifying the
radiative impact of cirrus clouds on the surface, top‑of‑atmosphere
(TOA), and atmospheric radiation budgets follows two general approaches.

3.5.1 Monitoring the Radiative Impact of Cirrus

FIRE seeks to better understand relationships between cloud parameters
and the TOA and surface radiative energy budgets. The strategy is to
obtain data sets suitable for investigating relationships between cirrus
cloudiness and the surface TOA radiative budgets. The required data sets
includes:

> • downwelling radiative fluxes at the surface,
>
> • upwelling radiative fluxes at the top‑of‑the‑atmosphere,
>
> • cloud heights, temperatures, and amounts, and
>
> • bulk cloud radiative properties.

It is important that these quantities be broadband and that the longwave
and shortwave spectral regions be resolved in a consistent manner.
Moreover, the data must be as simultaneous as possible in time and
space. In addition, rawinsonde observations of atmospheric temperature
and humidity structure, as well as surface pressure (P) and temperature
(T), are also required since atmospheric temperature and moisture also
impact the surface and TOA radiation budgets.

FIRE also encompasses efforts to evaluate models of atmospheric
radiative transfer in the infrared spectral region. SPECTRE (Spectral
Radiance Experiment) is a collaborative experiment (appendix G) to be
conducted in conjunction with FIRE intensive field observations. SPECTRE
was initially conceived as a clear‑sky experiment in order that the
atmospheric state be specifiable as rigorously as possible, thus denying
models their usual tuning latitude. However, SPECTRE will also operate
on all FIRE mission days and collect cloudy as well as clear sky data; a
cloudy atmosphere is not yet as rigorously specifiable as a clear one.
FIRE provides the best possible opportunity to constrain cloud
properties and thus squeeze models much harder than has been possible
before. SPECTRE observations should prove valuable in assessing the
radiative impact of cirrus. SPECTRE adds the additional requirement for
observations of:

> ‑ spectrally‑resolved downwelling infrared radiance at the surface,
>
> ‑ lower to mid‑tropospheric water vapor and temperature structure on a
> near continuous basis with high accuracy and high vertical resolution,
> and
>
> ‑ vertical profiles of ozone concentration and aerosol optical depth.

SPECTRE will use remote sensing techniques for water vapor (Raman lidar)
and for temperature (RASS: Radio Acoustic Sounding System), supplemented
by a tethersonde for profiling the lowest few hundred meters, and by
special launches of ozonesondes, hygrometersondes, and research sondes
with multiple temperature and moisture sensors.

3.5.2 Evaluating the Radiative Impact of Cirrus Using GCM\'s

Large‑scale atmospheric models provide an alternate means of quantifying
the radiative and more general climatic impact of cirrus clouds. GCM
studies on the radiative and climatic impacts of cirrus clouds will
continue (not necessarily under the FIRE umbrella) during FIRE Phase II.
Efforts will be made to intercompare the simulated TOA and surface
radiation budgets and cloud parameters with global climatologies such as
Earth Radiation Budget Experiment (ERBE) and ISCCP. New cirrus
parameterizations which are developed and verified against FIRE Phase II
data will be implemented in GCM\'s. Similarly, improved estimates of
cirrus radiative cloud properties, based on analysis of FIRE phase II
data, may be incorporated in GCM radiation codes.

3.5.3 Evaluating the Radiative Impact of Mid‑Latitude Cirrus Using
Regional Mesoscale Models

Mesoscale models can help bridge the gap between very detailed cloud
microphysical models (section 3.1) and global GCM\'s. Using regional
mesoscale models, short range forecasts will be made over the U.S.
region for the Cirrus IFO‑II cases. Having relatively finer resolution
than GCM\'s, these models may produce improved short range forecasts of
the dynamical fields and hence of the evolving cirrus cloud systems. An
important component of their regional verification will be to compare
model‑predicted vs. observed cloud and radiation parameters, utilizing
regional analyses of satellite data collected during FIRE. The latter
will be produced for some of the sensors and data parameters listed in
table 3. Also, efforts will be made to verify the predictions at one or
two grid points inside of the FIRE inner region against suitably
averaged FIRE data. New parameterizations of physical and radiative
properties for cirrus clouds will be tested. Some of them may be adapted
to existing global GCM\'s or incorporated into future finer resolution
GCM\'s.

Value‑added products in the form of \"ridded regional analyses of cloud
and radiation parameters over the U.S. region, are needed for objectives
3.5.2 and 3.5.3. Temporal and spatial resolutions of ∆x \~ 30 km and ∆t
\~ 3 hours would probably be acceptable. Perhaps a \"blended\" analysis
of satellite data which draws on data from different satellites and
sensors should be produced.

A list of the most important parameters that should be regionally
analyzed to help verify predictions of regional mesoscale models are:

> • cloud amount
>
> • cloud height vertical structure
>
> • TOA visible (VIS), infrared (IR) flux estimates and radiances
>
> • cloud optical thickness
>
> • cloud top temperature
>
> • cloud albedo, emissivity
>
> • phase of cloud particles
>
> • particle size of cloud particles
>
> • total cloud water
>
> • water vapor profile
>
> • clear sky TOA fluxes, clear sky albedo

Gridded analyses of the above data parameters are likely to be of direct
use in research efforts. In addition, detailed measurements obtained
from aircraft and active and passive sensors might be useful for setting
or revising values of fixed parameters in regional or larger scale
models or in GCM parameterizations if summary statistics (mean and
variance segregated to synoptic situations) of cloud properties can be
made available.

3.6 Surface‑Based Remote Sensing of Cirrus Clouds

Routine ground‑based remote sensing observations offer considerable
promise for characterizing the properties of cirrus clouds and their
environment over extended time periods. Active sensing technologies can
be applied including visible and infrared lidars, short wavelength cloud
radars, and long‑wavelength wind radars (profilers). These observations
provide \'ground‑truth\' corroboration for properties derived from
passive sensing techniques, especially retrievals from global
satellite‑based systems. A wide variety of passive remote sensing
technologies can also be utilized with considerably more spectral
coverage and resolution than presently available from satellite
platforms. Although, in most instances, the physical interpretation of
remote sensing observations is significantly more uncertain than for *in
situ* measurements, the benefits in terms of reduced costs and increased
temporal coverage in comparison to aircraft or balloon‑borne
observations are appreciable.

A primary advantage of active remote sensing of cirrus is the capability
to accurately measure, with unparalleled precision and resolution, the
temporal evolution of the height dependent structure of the clouds. The
fundamental parameter measured is the vertical profile of backscattered
intensity at the probing wavelength. Although this parameter has
intrinsic value, inference of more widely applicable cloud parameters is
highly desired, including profiles of cloud optical depth, particle
phase and habit, and cloud water content. The Doppler velocity spectrum
(radar and infrared lidar) and polarization of the returned signal are
also measured by some systems. The Doppler velocity spectrum provides a
means of estimating fall speeds of the ice crystals which are highly
dependent on crystal mass (and habit). These may be used to derive the
net vertical flux of ice mass which is a dominant component of the cloud
water budget. Polarization provides a measure of the phase and habit of
the cloud particles. In addition, high spectral resolution lidar offers
a much more direct measurement of the vertical structure of cloud
optical depth than achievable with other systems where appreciable
uncertainty is associated with the assumptions required to make this
inference. Current lidar and radar probing techniques offer the promise
of reasonably quantitative analysis of cloud composition. Since the
interaction of radiation with cloud particles depends both on the size
of the particles and the wavelength of the radiation and since a wide
range of particle sizes typically occur in cirrus, systems probing at
different wavelengths may respond quite differently to the same
population of cloud particles (Intrieri et al., 1990). This indicates
that the aggregate information derivable from coincident remote sensing
measurements using a variety of these systems may be increased in a
highly synergistic manner.

Similar possibilities exist in the combination of lidar and radar
observations with passive high spectral resolution measurements in
visible, near infrared, and infrared window regions, especially with
respect to determination of cloud optical properties (Grund et al.,
1990). When combined with surface‑based remote sensing observations of
ambient winds (wind profiler), moisture (microwave profiler), and
thermodynamic structure (infrared and microwave profilers), the
possibility exists for a rather comprehensive surface‑based observing
system.

The strategy for improving utilization of remote sensing observations
for quantitative characterization of cirrus clouds and their environment
during FIRE Phase II is *to intercompare coincident observations from a
wide variety of active and passive systems together with in situ
observations of cloud physical composition and atmospheric state.
Coincident observations are highly desirable.* Thus, the emphasis of
Phase II research will be on defining the potential synergistic increase
in quantitative information from combined systems encompassing:

> • active remote sensing systems, including
>
> \- dual polarization visible wavelength lidar,
>
> \- short‑wavelength Doppler radar,
>
> \- high spectral resolution visible wavelength lidar, and
>
> \- dual polarization, Doppler, infrared lidar (C02); and
>
> • passive remote sensing systems, including
>
> \- high spectral resolution, infrared, and near infrared
> spectrometers,
>
> \- microwave radiometers in water vapor absorption region, and
>
> \- narrow‑beam radiometers in visible, near infrared, and infrared
> window regions.

A complete listing of the data parameters required for each scientific
objective is outlined in table 1.

> ![](media/image1.wmf){width="6.495833333333334in"
> height="8.063194444444445in"}
>
> 4.0 CIRRUS INTENSIVE FIELD OBSERVATIONS (CIRRUS IFO‑II)
>
> 4.1 Synopsis
>
> FIRE Cirrus IFO‑II will address the problem of cirrus cloud
> development and impacts over a wide range of scales through the
> integration of models and observations. This experiment will provide a
> unique observational basis for improving the quantitative utilization
> of remote sensing observations from satellites and from the surface
> for investigating and monitoring cirrus clouds. The observational
> elements are summarized below and described in more detail in
> succeeding sections. It must be emphasized that the true value of the
> observations will derive from their use in evaluating and improving
> models and observing systems (data analysis algorithm) which can be
> used to extend the knowledge gained into the context of the global
> climate system.
>
> The Cirrus IFO‑II will be conducted in southeastern Kansas from
> November 13 to December 7, 1991 (section 4.2). The primary subjects
> are the extended large‑scale cirrus systems associated with the
> subtropical and midlatitude jet streams. Cirrus are expected to occur
> about 60% of the time during this period.
>
> Satellite data (section 4.3.1) will be collected at full spatial,
> temporal, and spectral (all channels) resolution from all
> geosynchronous and polar orbiting meteorological satellites viewing
> the region from 25N to 50N latitude and 75W to 125W longitude. Data
> from other satellites will also be obtained for this region, including
> Landsat. The ISCCP analysis products (CX) will be acquired as part of
> the Cirrus IFO‑II data sets. These data are integral to achieving the
> experiment objectives.
>
> Four surface‑based remote sensing sites will be fielded (section
> 4.3.2). The stations will be closer to each other than in IFO‑I (50 km
> versus 135 km) to better resolve the dominant scales of cloud
> organization. A greater diversity of the most sophisticated cirrus
> cloud remote sensing instrumentation will be deployed including
> polarization lidar, scanning cloud lidar, high spectral resolution
> lidar, infrared (CO2) Doppler lidars, short‑wavelength (mm) Doppler
> radars, high spectral resolution infrared interferometer
> spectrometers, and other radiometric sensors. A much greater effort to
> monitor ambient meteorological conditions using active and passive
> sensors is also planned. The strategy is to obtain coincident
> observations from as broad a range of complementary observing systems
> as possible. This will facilitate analyses that combine data from
> multiple systems. In this way, the aggregate information content will
> be maximized in that the limitations and uncertainties of individual
> systems may be compensated by others whose characteristics are quite
> different. Exploring this potential for synergism is a main theme for
> Cirrus IFO‑II (section 3.6). A complete suite of observing systems
> will only be possible at one location (the Hub) since some of these
> systems are unique. The instrument complement at the second site (R2)
> will also be extensive while the third site (R3) will be quite
> limited. A fourth site (Rla) near the Hub location is also planned to
> accommodate the operational requirements of the volume imaging
> (scanning) lidar (VIL; see section 4.3.2). This is different than the
> IFO‑I strategy of evenly spreading resources over the sites (Starr,
> 1987a). It should also be noted that the scanning systems will provide
> some coverage over the other sites given the closer spacing adopted
> for Cirrus IFO‑II. In addition, the closer site spacing will
> facilitate greater coincidence with airborne remote sensing and *in
> situ* observations since the site separation distance is comparable
> with the scales of typical aircraft sampling patterns.
>
> Four aircraft are proposed for the experiment, including one remote
> sensing platform and three *in situ* platforms (section 4.2.3). The
> remote sensing platform will be the high‑altitude NASA ER‑2, which
> will provide a \'satellite‑vie\"\' with significantly greater
> observing capability than presently available from satellites,
> including a down‑looking cloud lidar for the unambiguous detection of
> cloud top and internal cloud structure. Three *in situ* platforms are
> highly desirable given that cirrus cloud systems are often quite
> complex occurring in multiple layers over appreciable depths of up to
> 5 km (Starr and Wylie, 1990) and typically exhibit great spatial
> variability in physical structure, especially in microphysical
> structure (Heymsfield et al., 1990). Cloud microphysical structure
> represents the key linkage between dynamical and radiative processes.
> Knowledge of this relationship is fundamental for understanding cirrus
> cloud development and for evaluating and improving parameterizations
> of cirrus clouds and their effects for use in large‑scale models
> (GCM\'s). *Accurate knowledge of cloud microphysical properties is
> essential for achieving the FIRE Phase 1I scientific objectives*
> (section 3). Three *in situ* platforms (NCAR Saberliner, NCAR King
> Air, and University of North Dakota (UND) Citation) will significantly
> improve the sampling of microphysical cloud properties and allow a
> greater degree of flexibility in mission planning and execution in
> comparison to the Cirrus IFO‑I (two platforms).
>
> A number of key improvements have been made in aircraft
> instrumentation in comparison to IFO‑I. Ice particle number density
> size distributions will be observed clown to 10 \~m particle sizes.
> The lack of knowledge of the concentrations of particles smaller than
> 25 to 50 gm represented a major uncertainty in the analysis of the
> IFO‑I observations with important ramifications in the areas of cirrus
> cloud radiative interactions and remote sensing possibilities
> (Wielicki et al., 1990; Ackerman et al., 1990). The capacity for
> collecting actual crystals has also been significantly enhanced. These
> observations are essential for assessing ice crystal habit and
> morphology which impacts the processing of data from airborne optical
> microphysical probes and is an important factor in determining cloud
> development and radiative properties. These instruments have been
> developed and installed on the NCAR King Air and Sabreliner aircraft.
> In addition, accurate observations of ambient water vapor
> concentrations in and around cirrus clouds will be possible using a
> new cryogenic frost point hygrometer on the NCAR Sabreliner. These
> observations are critical for understanding cloud development and
> testing cloud models. The data obtained should help to resolve a
> number of pivotal uncertainties in our knowledge of cirrus clouds.
>
> The primary motivation for locating the Cirrus IFO‑II in the longer
> midwestern U. S. is the anticipated availability of nearly continuous
> observations from a mesoscale network of surface‑based wind profilers
> presently under construction by NOAA Environmental Research Laboratory
> (ERL) (figure 8, section 4.3.2.1.2). These data will serve to greatly
> enhance the value of both the synoptic‑scale observations and the *in
> situ* and remotely‑sensed cloud observations for developing, testing,
> and validating models of cirrus cloud development on scales ranging
> from very high resolution cloud models to regional mesoscale models
> and, ultimately, to cirrus parameterizations in large‑scale forecast
> models and GCM\'s. In particular, the data will permit derivation of
> upper tropospheric vertical motions at scales comparable to the
> mesoscale cirrus cloud features that are such a prevalent
> characteristic of extended large‑ scale cirrus cloud systems.
>
> A substantial increase in the collection of rawinsonde data is
> proposed for Cirrus IFO‑II (section 4.3.4). Three large‑scale case
> studies are planned where six‑hourly soundings will be taken for a
> 36‑hour period over much of the continental United States (et least 43
> stations). During the final twelve hours, three‑hourly soundings will
> be made over a more limited region of the central U.S. (15 stations).
> These data are absolutely essential for evaluating and improving
> large‑scale models of cirrus cloud development. Supplemental soundings
> (1800 UTC) from the inner 15 stations are also required on most other
> experiment days (10 additional days). Five Cross‑Chain Loran
> Atmospheric Sounding System (GLASS) rawinsonde stations will be used
> to support remote sensing studies and to resolve thermodynamic
> structure over an area defined by three NWS wind profiler stations.
>
> 4.2 Schedule and Location
>
> The FIRE Phase II Cirrus Intensive Field Observations campaign (Cirrus
> IFO‑II) will commence on November 13, 1991 and conclude 25 days later
> on December 7, 1991. Deployment and check‑out of surface‑based
> instrumentation and support facilities will occur during the week
> prior to November 13. Tear‑down and packing will occur during the week
> after December 7.
>
> The selection of the time period for the field campaign was motivated
> by a desire to minimize the occurrence of cirrus in association with
> deep convective systems and intense extratropical cyclones where
> obscuration by longer lever clouds is a serious impediment to
> surface‑based remote sensing and where the occurrence of intense or
> widespread precipitation greatly complicates analysis and modeling on
> the synoptic scale and the mesoscale. In addition, although some
> situations of an underlying snow‑covered surface are desired,
> conducting the experiment wholly over a snow background would clearly
> compromise the objectives in the area of satellite‑based remote
> sensing. The fall transition season most fully meets these
> requirements. Selection of the specific time period was based on the
> cloud climatology of Warren et al. (1986) and Hahn et al. (1984) and
> on a careful review of three years of daily GOES imagery. The primary
> target is the extensive cirrus sheets associated with the subtropical
> jet stream that frequent this location during this time period.
>
> The experiment will be conducted principally in southeastern Kansas.
> The area to the southeast of Neodesha was chosen as the location for
> the Cirrus IFO‑II operations (figure 1). The three primary sites that
> are shown are: the Hub site, consisting of an extensive suite of
> remote sensing instruments, and two other remote sensing sites with
> less extensive remote instrumentation at R2 and R3. The airport at
> Coffeyville, Kansas, will serve as the combined site for the Hub
> instrumentation (section 4.3.2), the aircraft base (section 4.3.3),
> and the mission operations and forecasting (section 4.4). The
> coordinates of the Coffeyville Airport are 37• 06\' N, 95• 34\' W, and
> 751 feet elevation. The R2 instrumentation (section 4.3.2) will be
> located southeast of Parsons, Kansas, at the recreation \"rounds of
> the Kansas Gas and Electric power plant. The coordinates of the power
> plant are 37• 18\' N, 95• 07\' N, and 865 feet elevation. The R3
> instrumentation (section 4.3.2) may be located at a site yet to be
> determined in northwestern Arkansas. Wind profilers will be deployed
> at the Hub, R2, and possibly R3 sites. The stations Hub, R2, and R4
> (NWS wind profiler station at Neodesha) form a 50‑km equilateral
> triangle. The locations of four CLASS‑type rawinsonde stations are
> also shown as are the locations of NWS rawinsonde stations (section
> 4.3.4). The cloud scanning lidar will probably be located about 20 km
> southwest of Coffeyville, at a site (Rla) yet to be determined.
>
> The specific location of surface remote sensing sites is critically
> contingent on the ability to conduct aircraft operations in and around
> cirrus clouds over and within a 100 km radius of the sites at
> altitudes ranging from about 20,000 to 42,000\' (\~6 to 13 km). Flight
> legs of from 20 km to more than 100 km in length will be flown at
> various altitudes (profiling) over this area (section 4.3.3). In
> addition, relatively rapid spiral descent of 10,000\' or more will be
> flown. Since our airspace requirements conflict with altitudes of
> commercial jet traffic and military aircraft operations, close
> coordination with the Federal Aviation Administration (FAA) and the
> Military Operating Areas (MOA\'s) is absolutely necessary to maximize
> FIRE aircraft operations. The Kansas City FAA Section Office has been
> fully briefed on the FIRE plans and, at this time, they foresee no
> major problem with the FIRE aircraft and lidar operations being
> conducted in this area. However, continued close cooperation with the
> FAA is necessary for both future planning and actual operations.
>
> The configuration show n in figure l illustrates the basic sampling
> strategy adopted for the experiment. First, all the remote‑sensing
> sites are located within the aircraft operations area. Second, the
> array is located on the expected downwind side of the densest part of
> the NWS

![](media/image2.pct){width="591.0in" height="707.0in"}

> profiler array. Third, the site separations approximate that of
> typical mesoscale cloud features and enable resolution of finer scale
> dynamic features (Hub, R2, and R4) in comparison to the NWS profiler
> grid. Fourth, the scanning lidar system (VIL) is located upwind and as
> close as operationally feasible (section 4.3.2) to the Hub site while
> the extensively instrumented R2 site is located downwind of the Hub
> site (for southwest flow).
>
> The missions operations center will be located at the Hub site at the
> Coffeyville airport. The three *in situ* aircraft and a majority of
> the surface‑based active and passive remote sensing instruments and
> scientists will also be located at this site. This cg‑location will
> ensure the direct participation of these scientist in mission planning
> and execution and provide direct access to unique information on
> current local cloud and meteorological conditions. The lack of
> involvement by the \"round site scientists in mission planning and
> execution was a significant weakness in the Phase I Cirrus IFO. A
> preliminary site survey indicates that there is good to adequate
> infrastructure available at the FIRE locations, including power, fuel,
> hangar space, telephone, field space, lodging, food, roads, etc.
> Preliminary contacts with the site owners/operators indicate no
> problems with our siting or operations, pending formal approval.
>
> 4.3 Observations
>
> 4.3.1 Satellite Observations
>
> Satellite data acquired during Cirrus IFO‑II are integral to the
> strategies adopted for achieving the objectives of FIRE Phase II
> (related FIRE science objectives given in parenthesis, see section 3)
> and will be used to:

• construct verification data sets for testing models of cirrus cloud
development (1,2),

> • develop and test models of radiative transfer in cirrus (3),
>
> • quantify and develop satellite remote sensing capabilities (4, 5),
> and
>
> • support operational scheduling of aircraft and surface observations.
>
> Satellite data will be collected for the region from 25N to 50N
> latitude and from 65W to 135W longitude over the Cirrus IFO‑II time
> period (section 4.2). The area of coverage encompasses the domain
> required for the studies of cirrus cloud development using regional
> (mesoscale) and GCM models, as well as including some areas with water
> backgrounds to simplify radiative analysis.
>
> The satellite data will be collected for the IFO region as follows:

i\. NOAA Advanced Very High Resolution Sounding Unit (AVHRR)
High‑Resolution

Picture Transmission (HRPT) data, 1 km resolution, 5 spectral bands, 2
satellites, day and

night.

ii\. NOAA AVHRR global area coverage (GAC) data, 5 spectral bands, 2
satellites, day and

night. This data is the reduced resolution version of the HRPT data.

iii\. NOAA TIROS Operational Vertical Sounder (TOVS) data, 20 spectral
bands, 2 satellites,

day and night.

iv\. GOES VISSR Atmospheric Sounder (VAS) imager data, 1 km resolution
visible charnel

and 8 km resolution infrared data, every 30 minutes. Only the GOES‑7
will be available,

as the proposed GOES‑NEXT satellite will not be launched until at least
early 1992.

v\. GOES VAS sounder data. VAS data should be simultaneous with the TOVS
data

whenever possible. In addition, on at least 7 of the 25 experiment days,
a 3‑hour period

coincident with aircraft flights should be used to obtain dedicated VAS
sounder data with

30 minute time resolution and 7 km spatial resolution.

vi\. Landsat Thematic Mapper (TM) data. For the IFO data period, 30
Landsat Thematic

Mapper scenes will be collected over the Cirrus IFO‑II surface sites and
the Gulf of

Mexico. Of the 30 candidate targets, only 10 will be selected for
analyses. Each scene

covers a 180 km square region.

vii\. ISCCP CX analyzed cloud properties. Cloud properties as analyzed
by the operational ISCCP algorithm are required for comparison to the
IFO cloud validation data.

viii\. Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol
extinction and water vapor data whenever the satellite tangent point is
over the IFO region.

ix\. Defense Meteorological Satellite Program (DMSP), 1.5 km resolution,
visible and

infrared images, Special Sensor Microwave Imager (SSM/I) radiances, 2
satellites (7:30

and 10 30 LST) daytime and nighttime, digital swath data.

x\. European Remote Sensing Satellite‑ I (ERS‑ 1 ) ATRS (Along Track
Scanning

Radiometer) I km resolution data within 30‑45 N, 85‑1O SW obtained from
European

Space Agency (ESA).

> xi\. METEOR data (TBD‑Wielicki).
>
> See table 2 for a complete listing of the participating satellites,
> sensors, and data requirements; see table 3 for a listing of the
> sensors, responsible principal investigators (PIs), and expected data
> parameters. A more detailed description of the satellite sensor
> characteristics is given in appendix A.

Table 2 ‑ Satellite Data Requirements for the FIRE Phase II Cirrus
Intensive Field Observations

![](media/image3.wmf){width="6.49375in" height="3.5708333333333333in"}

> Finally, satellite data are crucially important to the operational
> decisions made during the field experiment (section 4.4). Time series
> of half‑hourly GOES imagery will be used to characterize the movement
> and development of cirrus cloud systems (and upper tropospheric
> moisture structure) before and during their arrival over the
> operations area. Experience during IFO‑I showed this to be the single
> most important piece of information required for planning and
> execution of successful missions. These data will be available for
> mission planning in near‑real time via an interactive link between the
> mission operations center and the Man‑Interactive Data Acquisition
> System (McIDAS) at University of Wisconsin.
>
> 4.3.1.1 Simultaneous Satellite/Aircraft/Surface Site Observations
>
> One of the key elements of the FIRE plan is to obtain a set of
> aircraft/surface observations which are time and space coincident with
> satellite overpasses. The most critical coincidences are between
> surface lidars and either Landsat or NOAA AVHRR‑HRPT observations. The
> Landsat and HRPT data provide the highest spatial resolutions (28.5
> meter and 1.1 km respectively) allowing the most direct comparisons of
> satellite and surface measurements.

![](media/image4.wmf){width="6.493055555555555in"
height="8.341666666666667in"}

> For GOES and Landsat satellite data, these times are invariant from
> day to day (within less than a minute). For the NOAA polar orbiter
> satellites (TOVS, AVHRR), ERBS satellite (SAGE II), DMSP satellite,
> ERS‑ 1 satellite, and METEOR satellite, however, the exact time of
> overpass will vary by as mush as an orbital period (approx. 100
> minutes).
>
> Preliminary estimates of times of potential coincident satellite
> observations within the field sites (centered at 95.5 W, 37 N) and
> surrounding region (84 to 107 W, 27 to 47 N) are listed in appendix B.
> This will allow targeting of specific \"most opportune\" times for
> aircraft and surface operations.
>
> 4.3.2 Surface Radiation and Remote Sensing Observations
>
> Surface‑based radiation and remote sensing observations using active
> and passive techniques serve three main purposes (related FIRE science
> objectives given in parenthesis; see section 3). They will be used to:
>
> • determine cirrus cloud radiative, physical, and dynamic properties
> (1, 2, 3, 4, 6),
>
> • measure the surface radiation budget in the visible, near infrared,
> and infrared
>
> spectral regions and determine the influence of cirrus clouds on those
> budgets (5),
>
> • make high spectral resolution measurements of downwelling infrared
> radiance for
>
> comparison with radiative transfer model calculations (5, also see
> section 6.1).
>
> Surface‑based observing systems provide very high temporal (and, in
> many cases, much greater horizontal and vertical) resolution in
> comparison to satellite observations and significantly greater
> temporal (and vertical) coverage than aircraft observations. The
> strategy is to field as complete a complement of remote sensors as
> possible at one site, and then at a second, and then at a third.
> Because some of the systems are unique, it will not be possible to
> have an identical complement at each site. Thus, the first site (known
> as the Hub) will have at least one of every desired type of instrument
> available (the scanning VIL will be located within 20 km of the Hub).
> The second (R2) and third (R3) sites will necessarily have
> progressively less complete instrumentation. The strategy of having
> the greatest possible concentration of different instruments at the
> Hub, and to a lesser extent at the other sites, will *facilitate
> analyses that combine data from multiple systems.* In this way, the
> total information content of the data will increase in a highly
> synergistic manner in comparison to what would be achievable within
> the limited capabilities of each individual sensing system.
>
> FIRE seeks to provide as complete a description as possible of cirrus
> clouds and associated radiative and meteorological conditions within a
> relatively small mesoscale region. The surface‑based radiation and
> remote sensing data will support analysis and modeling of cirrus cloud
> development and variety of radiative transfer and satellite‑based
> remote sensing studies. A site spacing of 50 km corresponds to the
> scale of typical mesoscale cirrus cloud features (20‑100 km) and will
> also maximize coincidence of aircraft observations for the most sites
> (i.e., aircraft sampling legs are typically 30 to 100 km in length,
> section 4.3.3). The most important criteria in establishing site
> locations is to ensure that the airspace *overhead is* as
> *unrestricted* as possible, since these sites must serve as the locus
> of research aircraft operations. Synergism is a key theme of IFO‑II.
> FIRE seeks to explore the full remote sensing potential contained in
> temporally and spatially consistent data sets collected by active and
> passive sensors operating in various spectral regions.
>
> 4.3.2.1 Active Sensing Sensors
>
> Active remote sensing systems will offer excellent capabilities for
> conducting a comprehensive cirrus cloud experiment. They reveal in
> great detail the shape factors of clouds, such as cloud base and top
> heights, layers, and patches. The combined data allow for a unique
> characterization of cirrus cloud development and structure. For
> example, particle phase, habit, and orientation can be derived from
> polarization lidar observations. A similar capability has recently
> been added to the Wave Propagation Laboratory (WPL) cloud‑sensing
> radar (Kropfli et al., 1990). These data can be combined with the
> Doppler‑observed particle vertical motion to estimate particle mass
> and terminal velocity and, thus, updraft and downdraft wind speeds.
> These data can then be combined with the radar‑derived ice mass
> content to characterize the vertical ice mass flux and the mechanisms
> and scales involved in cirrus cloud generation. Simultaneous lidar and
> radar observations at multiple wavelengths will serve to refine the
> ice content estimates by providing additional information on particle
> size distribution in comparison to single‑wavelength probing.
> Simultaneous measurements will also provide information on the
> relationship between ice content and optical cross‑section of the
> cirrus clouds. Optical depth measurements provided by high spectral
> resolution lidar provide a near‑absolute calibration for
> depolarization and other lidar observations enabling a
> characterization of cloud optical properties in the visible at very
> high temporal and vertical resolution.
>
> Continuous longer tropospheric water vapor profiling (Raman) and
> temperature profiling (RASS) are essential for SPECTRE (appendix G and
> section 4.3.2.2). At night, the SPECTRE Raman lidar can give moisture
> profiles to 9‑10 km and may help answer important questions about the
> relation between humidity fields and cirrus formation. Obtaining an
> accurate characterization of upper tropospheric water vapor
> distributions is a very high priority (section 3.2).
>
> See table 4 for a complete listing of the surface remote active
> sensors and their locations, and tables 5a and 5b for a listing of the
> sensors, responsible principal investigators (PI\' s), and
>
> Table 4‑ List of planned surface instrumentation, locations, and
> responsible organizations for the FIRE Cirrus IFO‑II at the Hub, R2,
> R3, and Rla sensing sites (see figure 1).

![](media/image5.wmf){width="7.291666666666667in"
height="5.194444444444445in"}

> \* VIL may be located within 10‑20 km of Hub
>
> \*\* Contingent on license approval
>
> \*\*\* Up to 30 NWS wind profiler stations may participate (figure 2)
>
> expected data parameters. A more detailed description of the remote
> active sensors is given in appendix A.
>
> 4.3.2.1.1 Lidar Observations
>
> Infrared lidar (CO2) observations are expected to provide a measure of
> the vertical structure of cirrus optical properties (emittance) in the
> important 10.6 \~m window region. Polarization data at this wavelength
> are very different than at shorter, non‑absorbing wavelengths and
> might be used to address important questions about the infrared
> absorption efficiencies of the

![](media/image6.wmf){width="6.49375in" height="7.934027777777778in"}

> particles. A rocking scan about the zenith can provide information on
> the large dimension of oriented ice crystals. Similarly, the Doppler
> signal is expected to be different from the radar signal, because the
> latter is much more sensitive to large, faster‑falling particles.
> Combining these data with coincident radar‑derived ice mass
> concentrations and *in situ* microphysical observations obtained by
> aircraft should lead to significant improvements in the interpretation
> of the data from each of these sources (e.g., Sassen, 1987; Eberhard
> et al., 1989; Eberhard et al., 1990). Problems with signal attenuation
> that affect each system to differing degrees can be addressed in
> comparative studies (Sassen et al., 1989; Uttal et al., 1990).
>
> A rapidly scanning lidar has considerable value for capturing
> essentially Eulerian views of cirrus structure along and across the
> mean wind direction within a 50 km radius. These very high resolution
> data will provide a unique means to characterize cirrus cloud
> structure over scales corresponding to satellite observations and the
> field of view (fov) of radiative flux observations. Under conditions
> involving strong vertical wind shear, the distortions present in the
> cloud structure obtained from zenith operations can be assessed.
> Moreover, scanning lidar data would be a very useful tool for
> pre‑flight aircraft mission planning, particularly if the images can
> be made available in near real‑time to the mission scientist and
> aircrews (section 4.4). Potentially, these data could also be used to
> direct aircraft during mission execution.
>
> The planned location of the VIL at a distance of 10 to 20 km to the
> southwest of the Hub site attempts to maximize collection of data in
> an optimal sampling pattern for the science objectives while
> minimizing potential safety problems (section 5.10.2) and consequent
> interference with aircraft operations (section 4.3.3). Given that a
> southwesterly wind direction dominates during large‑scale cirrus
> events at this location at this time of year, this location will
> permit continuous cross‑wind scanning just upwind of the Hub site and
> *in situ* aircraft patterns. This crosswind VIL scanning pattern will
> map the time‑dependent cirrus cloud structure in a plane parallel to
> and of the same scale (100 km) as that being sampled by the remote
> sensing aircraft which will operate just downwind of the VIL sampling
> volume. The VIL site should be as close to the Hub as possible but at
> a sufficient distance to permit continuous aircraft operations over
> the Hub without their intersecting the VIL scan volume. In addition,
> this location permits VIL scanning in the upwind direction (away from
> the Hub and aircraft operations). Situations may require further
> restrictions on the VIL scan volume.
>
> Since maximum information content is derived from the multiple remote
> sensor approach when the various systems are examining the same cloud
> volume, emphasis will be given to zenith‑pointing operations (except
> for the scanning cloud lidar-VIL). However, the scanning Doppler
> systems designed to collect Velocity‑Azimuth‑Display (VAD) scans will
> coordinate their activities at predetermined time intervals
> (approximately every 30 minutes) to periodically characterize
> three‑dimensional cloud structure and vertical motion fields which are
> of very high priority.
>
> The lidars will operate in one of three modes, depending on the daily
> operations plans. The modes include the acquisition rate (period over
> which individual laser shots are averaged) and the pointing or scan
> direction of the lidars. The lidar frequency modes are defined as
> follows:
>
> MODE 1 ‑ maximum acquisition rate (less than 1 second)
>
> MODE 2 ‑ intermediate acquisition rate (greater than 1 second; less
> than 3 minutes)
>
> MODE 3 ‑ low acquisition rate (greater than 3 minutes)
>
> The pointing or scan directions for the lidars are as follows:
>
> Z ‑ zenith pointing
>
> D ‑ off‑zenith pointing
>
> SZ ‑ scan by stepping zenith angle
>
> SA ‑ scan by rotating azimuth angle
>
> SP ‑ scan by rotating about pointing direction
>
> The lidar acquisition times for each of the lidar operating modes are
> listed in table 6.
>
> Some examples of the specific operating modes for several lidars are
> given as follows:
>
> Polarization lidar (Utah): Mode 2SZ ‑ profile every 1 minute; scan by
> stepping zenith angle

CO2 Doppler lidar (WPL): Mode 1SA ‑ profile every 0.1 seconds; scan by
rotating azimuth angle

> Polarization lidar (LaRC): Mode 3Z ‑ profile every 15 minutes;
> constant zenith pointing
>
> 4.3.2.1.2 Wind Profiler Observations
>
> Data from the NWS operational wind profiler network (400 MHz), which
> is presently under construction in the central U. S., will also be
> acquired (figure 2). The availability of these
>
> Table 6 ‑ Lidar Profile Acquisition Times

![](media/image7.wmf){width="6.499305555555556in"
height="3.1430555555555557in"}

observations and their potential impact on efforts to analyze and model
cirrus cloud development was a prime factor in determining the location
and timing of the experiment. These data will enable greatly increased
resolution of the dynamic structure of the upper troposphere, especially
at the mesoscale, both through increased spatial resolution (the inner
7‑station ring) and increased temporal resolution (10 min.). Starr and
Wylie (1990) have shown the potential benefit of increased temporal
resolution in the analysis of cirrus cloud development (see also
Westphal and Toon, 1990; Nicholls et al., 1990). The inner ring of
stations will be fully operational well before the field campaign and it
is anticipated that all stations will be completed by that time. The
inner ring and the stations to the west of the FIRE operations area are
most critical and these have been targeted for first completion by the
NWS. Incorporation of these data into operational (and FIRE) analyses
should be straightforward. However, this has not been demonstrated. As a
result, FIRE has initiated a pilot project at the Pennsylvania State
University using a three‑site network to gain experience in preparation
for Cirrus IFO‑II.

> FIRE will also field up to three additional wind profilers for IFO‑II
> (figure 1, section 4.3.2.1). A 50 MHz system (PSU) will be deployed at
> the Hub site and will also serve as a RASS. A 5‑beam 400 MHz system
> (CSU) will be deployed at the R2 remote sensing site. An additional 50
> MHz system (PSU) may also be deployed at R3. Together with the
> operation NWS profiler at Neodesha (R4) these data will serve to
> characterize upper tropospheric dynamic structure at a scale
> corresponding to smaller scale cirrus cloud features such as
> longitudinal jet stream bands. Figure 3 shows the areas over which
> vertical motions can be inferred from divergence analyses of the NWS
> and FIRE wind profilers (section 4.3.2.1.3).
>
> ![](media/image8.wmf){width="7.958333333333333in"
> height="9.48611111111111in"}
>
> 4.3.2.1.3 Vertical Motion Observations
>
> Observations of vertical motions in cirrus clouds has always been very
> problematic and have significantly retarded progress in testing cloud
> development models (section 3.2). The array of wind profilers at the
> remote sensing sites provides a means of deriving area‑averaged
> vertical motions on the scale of mesoscale cloud features (\~50 km,
> see figure 3). One of the wind profilers (five‑beam system at R2) will
> have the capability to independently observe vertical motion on a
> scale of about 20 km. Scanning Doppler systems provide an alternate
> means to derive vertical motions at a comparable scale (\~20 km) also
> using kinematic techniques (VAD scans). Similar techniques can be
> applied to aircraft‑observed winds as in Gultepe et al. (1989).
> Doppler spectra derived from the zenith‑pointing CO2‑lidar
> observations can potentially, if sufficient resolution is achieved,
> provide an independent direct measure of vertical air motion and
> particle vertical motions within individual convective cells for
> comparison to values retrieved from Doppler radar observations at
> similar scale. These observations can be compared to *in situ*
> aircraft observations at a similar scale. The approach here is to
> apply every possible means to definitively characterize vertical
> motions in cirrus clouds. Only in this way can the present
> uncertainties in independent analysis of data from individual systems
> be reduced to an acceptable level.
>
> 4.3.2.2 Radiance and Radiative Flux Observations
>
> There are three aspects to the measurements of downwelling (and
> upwelling) radiances and radiative fluxes at the surface using passive
> radiometric instrumentation. See table 7 for a complete listing of the
> surface remote passive radiation and meteorological sensors; table 8
> for a listing of these sensors, responsible PIs, and expected data
> parameters. For a more detailed description of the remote passive
> radiation and meteorological systems, see appendix A.
>
> Data from three instruments are particularly useful for characterizing
> cirrus cloud optical properties, especially in combination with lidar
> and other active measurements. They are:
>
> ‑ sun photometers (Hub),
>
> ‑ narrow‑beam infrared window (l0 ‑ 12 um) radiometers (Hub and R2),
> and
>
> ‑ high spectral resolution (1 cm-1 from 4 to 16 gm) interferometer
> spectrometers
>
> (Hub and R2).
>
> These measurements will serve to define cirrus cloud optical depth in
> the visible and infrared, and cirrus cloud infrared effective
> radiating temperature and emittance.

The effects of cirrus clouds on the downwelling solar radiation at the
surface will be assessed using narrowband and broadband solar flux
radiometers at the Hub and R2 sites where

> ![](media/image9.wmf){width="8.097222222222221in"
> height="9.38888888888889in"}
>
> Table 7 ‑ List of planned surface instrumentation, locations, and
> responsible organizations for the
>
> FIRE Cirrus IFO‑II at the Hub, R2, R3, and Rla passive remote sensing
> sites (see figure 1).

![](media/image10.wmf){width="7.666666666666667in"
height="5.069444444444445in"}

> \# A total of 48 NWS rawinsonde sites may participate (17 intensively,
> see figure 8)
>
> \## A total of five systems will be deployed (three additional CLASS
> sites, see figure 1)
>
> cloud imaging systems will also be deployed. Besides the satellite
> observations (section 4.3.1), direct measurements of cloud and aerosol
> optical depths using a high spectral resolution lidar and sun
> photometers at the Hub site as well as cloud cover observations from a
> scanning lidar system are needed. Low lever aircraft observations of
> the spatial distribution of surface albedo and solar radiative fluxes
> are also desired (section 4.3.3). Surface measurements of
> meteorological parameters using portable automated mesonet stations
> (PAMS) provided by NCAR are very important for radiative transfer
> calculations, particularly in the IR, and are needed for satellite
> retrieval studies.

Efforts to measure the surface radiation budget and to determine the
effects of cirrus clouds on the surface radiation budget will be
conducted in collaboration with the NASA Surface

Table 8 ‑ Data Parameters for Surface Remote ‑ Passive Radiation and
Meteorology Sensors

> ![](media/image11.wmf){width="7.375in" height="8.5in"}
>
> Radiation Budget (SRB) program and the Spectral Radiation Experiment
> (SPECTRE). An SRB objective is to perform an intercomparison of
> various infrared flux radiometers under all‑sky conditions
> (continuation of an international intercomparison project under the
> World Meteorological Organization (WMO)). The SRB measurements will be
> obtained *only at the Hub site.* Instrumentation will include various
> broadband infrared flux radiometers.
>
> SPECTRE\'s main objective is to accurately measure the zenith infrared
> radiance at high spectral resolution while simultaneously profiling
> the radiatively important atmospheric characteristics. These data can
> then be used to meaningfully test detailed infrared radiative transfer
> models of the atmosphere (appendix G). The key features of SPECTRE are
> continuous, instantaneous profiles of atmospheric temperature,
> humidity, aerosol, and cloud; continuous high resolution spectra of
> downwelling infrared radiation; radiance rather than flux
> measurements; careful and frequent radiometric calibration in the
> field; and redundant measurements. Daytime and nighttime observations
> will be taken in clear sky situations and when cirrus are present.
> Measurements will be taken during FIRE missions.
>
> SPECTRE measurements will include:
>
> ‑ high spectral resolution observations of downwelling infrared
> radiance,
>
> ‑ cirrus cloud and aerosol optical depths,
>
> ‑ atmospheric profiles of temperature, water vapor, and ozone, and
>
> ‑ trace gas concentrations at the surface.
>
> Radiometric instrumentation at the Hub site will include:
>
> ‑two interferometer spectrometers (0.2 cm-l and \< 1 cm-1 from 4 to 16
> gm, respectively),
>
> ‑ grating spectrometer (0.5 cm- 1 from 8 to 25 \~m),
>
> ‑direct solar spectrometer (0.002 cm- 1 from 2 to 20 \~m),
>
> ‑ sun photometer, and
>
> ‑ on‑site blackbody radiometric calibration facility.
>
> Additional SPECTRE instrumentation and measurements will include Raman
> lidar (water vapor profiling to 3 km in the day time; 9 km at night),
> radio‑acoustic sounder (RASS, virtual temperature sounding to 8 km),
> ozone sondes (ozone sounding to 30 km), Dobson total ozone instrument,
> tethersonde (temperature, water vapor, and ozone sounding to 300 m),
> research radiosonde system (humidity, temperature, winds), surface
> meteorological observations (pressure, temperature, humidity, and
> aerosols), dedicated longer and mid tropospheric rawinsonde
> observations (P, T, and humidity), and flask samples of trace gases
> (carbon dioxide,
>
> methane, nitrous oxide, and freons). Table 9 summarizes the
> instruments that will participate in SPECTRE.
>
> The use of multiple spectrometers provides redundancy and, together
> with a strong effort at absolute calibration, will insure that the
> highest possible radiometric accuracy is achieved. The tethersonde
> observations will fill the near‑field \'blind spot\' typical of remote
> sensing profilers while FIRE rawinsonde observations will also serve
> to define the atmospheric state above the lever reached by the remote
> sensors. Data from the FIRE lidars will be used to determine
> atmospheric aerosol optical depths and to characterize the properties
> of cirrus clouds.
>
> Table 9 ‑ Listing of instruments participating in SPECTRE
>
> ![](media/image12.wmf){width="7.055555555555555in"
> height="4.805555555555555in"}
>
> 4.3.2.3 Radiometer Calibration Guidelines
>
> Calibration and cross‑calibration of all (satellite, aircraft, and
> surface) radiometric sensors is critical (section 3.4). The primary
> responsibility for radiometer calibration and the error analysis of
> data collected rests with the principal investigator in charge of each
> instrument. However, to facilitate such calibration and especially to
> determine the relative accuracy of different radiometers measuring
> similar quantifies, the following strategy is proposed.
>
> \(1\) [Absolute Reference Calibration]{.underline}
>
> Each radiometer should have one or more absolute calibrations
> available for reference prior to the IFO. These absolute calibrations
> may be carried out by a variety of techniques**,** as outlined below.
> We ask, therefore, that each investigator document his procedure,
> together with an objective error analysis of each instrument, and that
> this documentation be placed on file at the FIRE Project Office prior
> to the start of the IFO.
>
> \(a\) Broadband radiometers
>
> Dr. John DeLuisi has kindly volunteered to calibrate broadband
> pyranometers and pyrgeometers sent to him at his calibration facility
> in Boulder. He will check the absolute calibration as well as the
> cosine response to direct solar irradiance. In the absence of a
> similar absolute calibration done elsewhere, individual investigators
> are therefore encouraged to avail themselves of this opportunity about
> 5 months before the IFO.
>
> \(b\) Spectral radiometers
>
> There are two parts to the calibration of spectral radiometers:
> spectral calibration and radiometric calibration. Spectral calibration
> is important whenever atmospheric radiation is varying rapidly with
> wavelength across the instrument channels ‑‑ for example across
> absorption bands, or in the tails of the solar and terrestrial
> blackbody spectra between 2 and 6 \~m. For instruments with a few
> broad channels selected by bandpass filters or other optical elements,
> spectral calibration is rarely done in the field at all, and usually
> not even pre‑ or post‑field; instead, faith is placed in the bandpass
> calibration certifications from the manufacturers of the optical
> elements. While such optical elements are known to undergo drift and
> degradation with time, this neglect is probably all right since
> spectral calibration errors are typically less than radiometric
> calibration errors (\>10%) in broad channel instruments. Only if such
> instruments claim accuracies better than 10% must the quality of their
> spectral calibration be called into question.
>
> For instruments with contiguous channels so narrow that a meaningful
> spectrum can be defined, spectral calibration is much easier-one
> merely checks that the measured peaks fall at wavelengths of (very
> precisely) known atmospheric absorption band peaks. For example, the
> High spectral resolution Interferometer Spectrometer (HIS)
> interferometer that will operate both on the ER‑2 and at the Hub is
> compared, peak by peak, with calculated spectra based on the AFCL line
> parameters tape. In the shortwave, where there are far fewer
> absorption bands than in the longwave, additional spectral calibration
> in the laboratory, viewing sources with emission features at known
> wavelengths, is highly desirable. The Airborne Visible/Infrared
> Imaging Spectrometer (AVIRIS) spectrometer, for example, views 23
> mercury emission fines covering the spectral region 0.4‑2.4 μm.
>
> In the longwave, absolute radiometric calibration is quite direct-the
> spectral radiometer views a laboratory blackbody at several different
> blackbody temperatures. The most sophisticated instruments also have
> internal blackbodies at one or even two temperatures. Careful
> investigators find it necessary to calibrate frequently to catch the
> very prevalent drifting of longwave radiometers. For example, the ER‑2
> HIS interferometer views a blackbody both pre‑ and post flight as well
> as internal blackbodies during flight. All the SPECTRE radiometers
> will be calibrated every few hours against a custom‑built blackbody
> with temperature continuously variable from 100 to 300 K and a
> state‑of‑the art accuracy of about 1%.
>
> In the shortwave, absolute radiometric calibration is much more
> indirect and therefore subject to considerably larger errors. Even as
> carefully calibrated an aircraft shortwave spectral radiometer as
> AVIRIS claims no better than 3‑5% accuracy. Typically, calibration
> must be transferred from an NBS/NTIS standard source to an integrating
> sphere, which then acts as a secondary standard. A carefully
> maintained and continuously verified integrating sphere, such as those
> at NASA Goddard Space Flight Center (GSFC), NASA Ames Research Center,
> and Jet Propulsion Laboratory, can be accurate to 1%. But there are
> many more problems with integrating spheres than with low‑temperature
> blackbodies, including lamp and coating degradation, making accuracies
> better than 10% extremely difficult to achieve outside of national
> laboratories. There are no plans to have an integrating sphere either
> at the surface sites or at the ER‑2 airport, and thus there will be no
> absolute calibration of shortwave spectral radiometers against a
> common standard in the field. In view of this, it seems highly
> desirable for NASA to offer the use of its integrating spheres for
> pre‑ and/or post flight calibration of all FIRE shortwave spectral
> radiometers.
>
> \(2\) [Relative Calibration/Intercomparison]{.underline}
>
> Each radiometer should undergo a relative calibration with respect to
> the other radiometers at the stars (and, possibly, the finish) of the
> IFO, at a common location at the surface.
>
> This intercomparison should serve to identify any drifts since the
> prior absolute calibration, as well as potential effects due to a
> different spectral distribution of the radiation under field
> conditions.
>
> For the broadband surface radiometers, this relative calibration is
> relatively straightforward.
>
> For the surface and aircraft spectral radiometers, the intercomparison
> may prove more difficult, and here it is proposed to make use of a
> secondary reference detector (Professor Cox\'s scanning radiometer),
> and secondary reference sources (Dr. Spinhirne\'s light box and cola
> chamber). A blackbody calibration facility will be part of the SPECTRE
> component. We are hoping to have all aircraft and surface radiometers
> collocated at the stars of the IFO for this intercomparison.
> Additional strategies may be developed as experience is gained on this
> problem.
>
> \(3\) [Relative Intercomparison of Aircraft Instruments]{.underline}
>
> Since some of the instruments are sensitive to ambient temperature and
> pressure, and since the surface intercomparisons may not be practical
> for some instruments, it is proposed to dedicate a portion of the
> flight time to instrument intercomparison. To be worthwhile, this
> would have to take place at the same altitude over a uniform
> underlying surface (e.g., Gulf of Mexico), and with no cloud above the
> aircraft. Only one such intercomparison involving the ER‑2 may be
> possible, due to its flight characteristics, but the other aircraft
> should attempt more frequent intercomparisons, at least until the data
> becomes repetitive.
>
> \(4\) [Absolute and Relative Calibration of Satellite and Aircraft
> Spectral Radiometers]{.underline}
>
> One of the critical remote sensing issues for studies of cloud optical
> properties is to obtain accurate absolute and relative calibration for
> solar reflectance channels of both satellite and aircraft spectral
> radiometers. An example of the need for accurate absolute calibration
> (approx. 5%) is the determination of cloud optical depth and cloud
> particle size. An example of the need for accurate relative
> calibration (approx. 1‑2%) is the determination of the anisotropy of
> reflected radiation for use as a test of scattering phase function for
> cirrus, and 3‑D cloud structure for stratocumulus. A four‑fold
> approach will be used to determine the consistency of absolute
> calibration during FIRE.
>
> \(i\) [Calibration of satellite radiometers]{.underline} using
> overflights of White Sands and calibrating against surface based
> measurements of surface and atmospheric properties (AVHRR + GOES,
> Whitlock; Landsat, Slater).
>
> \(ii\) [Stability checks of AVHRR]{.underline} starting in 1979 using
> the Libyan desert. (Staylor, 1990), along with the stability checks
> provided by ISCCP monitoring of clear-sky and planetary albedo.
>
> \(iii\) [Calibration of aircraft spectral radiometers]{.underline}
> (ER‑2 and Sabreliner) against ground‑based integrating spheres before
> and after the experiment.
>
> \(iv\) [Use of the ER‑2 MAS radiometer as a transfer
> standard]{.underline} for relative calibration of satellite and
> aircraft spectral radiometers
>
> 4.3.3 Aircraft Observations
>
> Airborne observations are an essential component of the FIRE Cirrus
> IFO‑II strategy. As remote sensing platforms, research aircraft
> provide a means to collect very high resolution, multispectral
> radiometric measurements at wavelengths used by present and *future*
> satellite observing systems (satellite simulators) and at viewing
> geometries (scanning systems) specifically designed to facilitate use
> of the data in resolving fundamental uncertainties with respect to
> cirrus radiative properties (science objective 3, section 3). The
> airborne remote sensing observations are a key element in efforts to
> quantify the capabilities and limitations of satellite observing
> systems (science objective 4). The value of the passive sensor data is
> greatly enhanced by the acquisition of simultaneous observations of
> cloud physical properties using active systems such as lidar and
> radar. Direct measurements of broadband radiative fluxes enable the
> effects of cirrus on the radiative budget of the atmosphere and
> surface (science objective S) to be quantified.
>
> As *in situ* observing platforms, aircraft provide a means to directly
> observe cloud physical properties, especially the microphysical and
> radiative properties, and to characterize the dynamic, thermodynamic,
> and radiative structure of the cloud and its environment. Acquisition
> and analysis of these observations is crucial to the success of
> efforts to characterize and model cirrus cloud development (science
> objectives 1 and 2), particularly with respect to understanding some
> of the most problematic but critical aspects (section 3.2).
> Significant improvements have been made in the capability for
> resolving the spectral and angular distribution of radiance, for
> characterizing the turbulent fluctuations of dynamic and thermodynamic
> quantifies, for observing the habits and numbers of ice crystals clown
> to about 10 \~m in size, and to accurately observe atmospheric water
> vapor contents. Efforts to develop an airborne polar nephelometer to
> make direct measurements of cirrus particle phase functions are in
> progress and, hopefully, the nephelometer will be installed on the
> NCAR King Air in time for the Cirrus IFO‑II. When combined with
> satellite, airborne, and surface‑based remote sensing observations,
> the *in situ* observations provide \'\"round truth\' for analysis of
> these data and improving remote sensing capabilities (science
> objectives 4 and 6) as shown, for example, by Sassen et al.(l989),
> Wielicki et al. (1990), Spinhirne and Hart (1990), Kinne et al.
> (1990), Ackerman et al. (1990), and Hammer et al. (1990). The
> microphysical data provide basic information needed to characterize
> fundamental relationships between cirrus cloud optical and physical
> properties (science objective 3.3).
>
> 4.3.3.l Aircraft Platforms and Instrumentation
>
> Deployment of four aircraft is proposed for FIRE Cirrus IFO‑II. They
> are:
>
> • the NASA ER‑2,
>
> • the NCAR Sabreliner,
>
> • the NCAR King Air,
>
> • the UND Citation.
>
> The ER‑2 is a *remote sensing platform* that will operate at constant
> altitudes (65,000\') well above the cirrus clouds. The Sabreliner,
> King Air, and Citation are primarily *in situ* platforms. The
> Sabreliner will be utilized to sample high cirrus layers and the upper
> portion of cirrus above the operating ceiling of the King Air. The
> King Air will sample longer cirrus (and altostratus) layers and the
> longer portions of high cirrus to its operating ceiling. The Citation
> will solely be used to measure the vertical profiles of microphysical
> parameters within the cirrus clouds, usually over a surface site not
> being overflown by the Sabreliner, i.e. over R2 if the Sabreliner is
> over the Hub site. The Citation is capable of operating at higher
> levers (and greater range) than the Sabreliner since extended systems
> of subtropical jet stream cirrus are anticipated where cloud top
> heights may exceed the operating ceiling of the Sabreliner on some
> occasions.
>
> See table l0 for a complete listing of the aircraft sensors,
> responsible PIs, and expected data parameters. More detailed
> descriptions of the aircraft instrument characteristics are given in
> appendix A.
>
> [NASA ER‑2]{.underline}
>
> The ER‑2 instrument complement will include:
>
> • nadir‑pointing, cloud and aerosol lidar system (CALS),
>
> • scanning multispectral MODIS‑N Airborne Simulator (MAS),
>
> • scanning, multispectral, solar radiometer,
>
> • scanning, multispectral, millimeter imaging radiometer,
>
> • nadir‑pointing, high spectral resolution, interferometer
> spectrometer (HIS),
>
> • broadband infrared flux radiometer,
>
> • broadband solar flux radiometers (total and near infrared),
>
> • nadir‑pointing, narrow‑beam, infrared (split window) radiometer,
>
> • spectral electro optic camera, and
>
> • grating scanning radiometer (?).
>
> The scanning radiometers will duplicate channels found on present and
> future satellites and other channels potentially important for the
> remote sensing of cirrus and other clouds, specifically in the near
> infrared (MAS). These sensors have very high spatial resolution (45 m
> for MAS). The CALS will provide \'cloud‑truth\' as in IFO‑I. The HIS
> instrument is nearly identical to one of the interferometer
> spectrometers at the Hub site. The high spectral resolution and
> accurate calibration of the HIS provides a capability to simulate most
> any present or future satellite instrument operating in the infrared.
> The broadband instruments measure both the upwelling and downwelling
> fluxes. The ER‑2 will be based at San Antonio, Texas, due to the high
> winds and possible snow in Kansas.
>
> [NCAR Sabreliner]{.underline}
>
> Sabreliner instrumentation will include:
>
> • cloud physics instrumentation, including
>
> ‑ liquid water probes (Rosemount and PMS),
>
> ‑ cloud particle size spectrometer (PMS OAP 2D‑C, 2D‑P),
>
> ‑ continuous ice particle sampler (CIPS, new),
>
> ‑ ice particle collection devices (NCAR ice rod, Mohnen ice stick,
> new),
>
> ‑ cloud condensation nucleus chamber (new), and
>
> ‑ aerosol detectors (ASASP), \'air bag\' samples and composition
> analyzers (new),
>
> • meteorological sensors (pressure, temperature, and wind components
> at 50 Hz),
>
> • Lyman ‑ alpha hygrometer,
>
> • cryogenic frost point hygrometer (new),
>
> • uplooking, total direct‑diffuse, multispectral, solar flux
> radiometer (TDDR),
>
> • uplooking and downlooking, multi‑angle (bugeye), visible radiance
> radiometer,
>
> • nadir‑pointing, spectrally scanning solar radiometer (SPERAD),
>
> • broadband solar flux radiometers (total and near infrared),
>
> • broadband infrared flux radiometers,
>
> • narrow‑beam, nadir‑pointing infrared (window) radiometer, and
>
> • forward and side‑viewing VCR cameras.
>
> The broadband flux radiometers are being upgraded to the same
> instruments flown on the ER‑2 and will monitor upwelling and
> downwelling fluxes. The TDDR and SPERAD instruments also represent
> major improvements in radiometric instrumentation on this platform.
> Both have high spectral resolution and high accuracy and are
> specifically designed for application in sensing cloud radiative
> properties.
>
> Of particular note is the new small ice particle probe (CIPS) for
> measurement of the particle number density size distribution down to
> 10 \~m particle sizes. The 2D‑C and 2D‑P probes are unable to respond
> to particles smaller than about 50 gm at Sabreliner airspeeds (and 25
> \~m at King Air airspeeds) where significant and uncertain
> \'corrections\' are required for particles smaller than about 100 \~m.
> This basic limitation is associated with much of the remaining
> uncertainty in analysis and modeling of IFO‑I data. For IFO‑II, the
> Sabreliner will also be equipped with ice particle collection devices.
> The new cryogenic frost point hygrometer (Sabreliner and possibly King
> Air) will permit accurate observations of upper tropospheric water
> vapor content which have not been available. The meteorological data
> will be recorded at 50 Hz (analysis at 10 Hz) to better resolve
> turbulence characteristics and turbulent fluxes in comparison to IFO‑I
> (1 Hz). In addition, measurements of aerosol and cloud condensation
> nuclei (CCN) concentrations and composition will be obtained from the
> Sabreliner which will contribute to resolving basic uncertainties with
> respect to cirrus generation and microphysical development (e.g.,
> Sassen and Dodd, 1989; Sassen, 1989; and Heymsfield and Sabin, 1989).
>
> [NCAR King Air]{.underline}
>
> The King Air instrument complement will include:
>
> • cloud physics instrumentation, including
>
> ‑ liquid water content probes (Johnson‑Williams, Rosemount, and PMS),
>
> ‑ cloud particle size spectrometers (high‑resolution FSSP‑300, PMS OAP
> 2D‑C and 2D‑P),
>
> ‑ ice particle collection device, and
>
> ‑ polar nephelometer (?);
>
> • meteorological sensors (pressure, temperature, and wind components
> at 50 Hz),
>
> • cryogenic frost point hygrometer (new) and Lyman‑alpha hygrometer,
>
> • uplooking and downlooking, broadband solar, visible, and infrared
> flux radiometers,
>
> • narrow‑beam, nadir‑pointing, infrared (window) radiometer, and
>
> • forward and side‑viewing VCR cameras.
>
> The meteorological data will be recorded at 50 Hz (analysis at 10 Hz)
> to better resolve turbulence characteristics and turbulent fluxes in
> comparison to IFO‑I (1 Hz). The new small ice
>
> particle profiles will measure the particle number density size
> distribution down to 10 μm particle sizes. A cold room for analysis of
> ice crystal samples is located near the airfield.
>
> [University of North Dakota Citation]{.underline}
>
> The Citation instrument complement will include, at a minimum:
>
> • cloud physics instrumentation, including
>
> ‑ liquid water content probes,
>
> ‑ cloud particle size spectrometers (FSSP, PMS OAP 1‑C, 2D‑C, and lD‑P
>
> probes), and
>
> • meteorological sensors (pressure, temperature, humidity, and wind
> components at 24 Hz).
>
> Addition of the new small ice particle probe and the new cryogenic
> frost point hygrometer is highly desirable. Instruments for detecting
> aerosol and CCN concentration are also desirable.
>
> 4.3.3.2 Aircraft Sampling Strategies
>
> Three general principles guided development of sampling strategies for
> the aircraft platforms:
>
> a\. analysis of results from the Phase I field deployment indicates
> that *greater coordination of aircraft operations is highly desirable*
> (e.g., Kinne et al., 1989; Wielicki et al., 1990) to facilitate the
> utility of the data obtained in achieving the science objectives. What
> is required is that all aircraft operate in close proximity to the
> surface sites (and each other), especially over the Hub site, and that
> operations be coordinated with overpasses of the NOAA polar orbiting
> satellites (or Landsat) to the extent permitted by operational
> considerations and cloud conditions.
>
> b\. the patterns flown should be based on the *simplest possible
> configuration* suited to the
>
> mission objectives and platform and analysis capabilities in order
> that mission planning be
>
> streamlined and that execution of the mission proceed in a
> well‑coordinated fashion. In essence,
>
> too many options create confusion which can negatively impact the
> success of a mission.
>
> *c. calibration and intercomparison* of radiometric instrumentation on
> the aircraft platforms, on satellites, and at the surface sites will
> have a high priority and will seek to

Table 10a ‑ Data parameters for aircraft sensors

> ![](media/image13.wmf){width="7.555555555555555in"
> height="8.61111111111111in"}
>
> Table 10b ‑ Data parameters for aircraft sensors
>
> ![](media/image14.wmf){width="7.5in"
> height="5.555555555555555in"}reference all measurements to a single
> standard. In particular, as much commonalty as possible is desired for
> radiative flux sensors with respect to instrument design and bandpass.
> Besides an increased effort at absolute calibration (blackbody and
> integrating sphere calibrations on the \"round), it is important that
> intercomparisons be performed in the field over *the actual range of
> operating conditions.* In this way, the effects of temperature and
> density (airspeed and altitude) variations on sensor performance can
> be firmly established.
>
> [Remote Aircraft Flight Patterns]{.underline}
>
> For most missions, the remote sensing aircraft (NASA ER‑2) will *fly
> the same basic racetrack pattern* (figure 4). To the extent permitted
> by navigational accuracy, the patterns will be flown over exactly the
> same geographical coordinates at an altitude of 65,000\'. The starting
> time of each leg will be coordinated to ensure the greatest
> coincidence of the data in the vicinity
>
> ![](media/image15.wmf){width="7.027777777777778in"
> height="8.472222222222221in"}
>
> of the surface remote sensing sites. In general, the racetrack legs
> (lever straight fines during which data is obtained) will be *150 km*
> in length. Longer legs (up to 500 km in length) may be flown for a few
> selected missions. Except for a few special missions, the approximate
> midpoint of the racetrack legs will be located *over or just downwind
> of the Hub site* (figure 5) subject, of course, to the continued
> presence of clouds over the target area. One of two possible
> orientations (aircraft heading) will be selected for a given mission
> based upon the science objectives for that mission. In the first, the
> racetrack will be oriented *perpendicular to the solar plane.* Thus,
> the orientation of successive racetracks will change in time as the
> solar position changes. This will permit the cross‑track scanning
> radiometers on the ER‑2 to resolve the principal forward and backward
> scattering peaks of the cloud bi‑directional reflectance pattern.
> Knowledge of the bidirectional reflectance of cirrus is critically
> needed for satellite‑based remote sensing applications. Knowledge of
> the cloud bi‑directional reflectance also places significant
> constraints on possible ice particle scattering phase functions which
> is a major source of uncertainty in our understanding of radiative
> transfer in cirrus and the relationship between cirrus cloud optical
> and physical properties. In the second orientation, the flight legs
> will be flown *perpendicular to the wind direction at cirrus
> altitude.* This provides the most effective mapping of cirrus cloud
> structure in time and space, as illustrated in figure 6. Movement of
> the clouds in time is used to provide a second horizontal dimension in
> this Eulerian cloud mapping mode. Data taken in this manner will be
> highly useful for characterizing the cloud scene in comparison to
> satellite observations, for use in cirrus cloud development studies,
> and for characterizing the effects of cirrus clouds on the surface and
> atmospheric radiative budgets. It is expected that the *cross‑wind
> tracks will often be approximately perpendicular to the solar plane*
> during some part of a mission since extended cirrus systems often
> occur in southwesterly flow at this time of year (November 13 ‑
> December 7) and missions will usually overlap the time of the
> afternoon NOAA polar orbiter overpass (\~1430 LST).
>
> [*In situ* Aircraft Flight Patterns]{.underline}
>
> Prior to the stars of he Cirrus IFO‑II experiment, the NCAR King Air
> and Sabreliner will fly in a check‑out and research mode to sample
> cirrus wave clouds in Colorado over a 10‑day period. The purpose of
> these flights is to field test the new equipment so that changes or
> improvements can be made prior to the aircraft departing for
> Coffeyville, Kansas. The instrumentation will be flight tested in
> definable and very simple conditions to provide benchmarks for the
> instrument accuracies.
>
> There are three basic flight patterns that will be used for the *in
> situ* aircraft (figure 4). They are:
>
> • the racetrack pattern,
>
> • the step‑down/step‑up pattern, and
>
> • the spiral descent.
>
> **FIRE Cirrus IFO‑II**
>
> **Aircraft Flight Patterns**
>
> **(Pattern 2 Mission, Eulerian)**

![](media/image16.wmf){width="7.638888888888889in"
height="4.666666666666667in"}

Figure 5 ‑ Schematic of coordinated aircraft flight patterns for FIRE
Cirrus IFO‑II Eulerian Mission, Pattern 2.

![](media/image17.wmf){width="7.583333333333333in"
height="7.569444444444445in"}

Figure 6 ‑ Schematic plan‑view of the FIRE Cirrus IFO‑II aircraft and
surface observing site sampling patterns for a Eulerian Mission, Pattern
2 (figure 5) transformed into a coordinate system moving with the mean
wind (and clouds) at cirrus altitude. Wind direction is from the top of
the page to the bottom. Thus, observations at the bottom of the
illustration were taken first. The scanning lidar (VL) provides
near‑continuous coverage over the entire span.

> The [racetrack pattern]{.underline} is primarily used for observing
> the radiative budgets of cirrus clouds and the radiative impact of the
> clouds on the radiative budgets of the atmosphere and surface. This
> pattern is also well‑suited for characterizing the statistical
> properties of bulk cloud radiative properties and horizontal cloud
> structure and for observing turbulence characteristics and turbulent
> fluxes. It can be used to generate vertical profiles but the number of
> levers is limited by the time consumed in making the reverse heading
> legs at each altitude (the reverse heading legs provide a means of
> normalizing for the cosine response of the flux radiometers).
>
> The [step‑down/step‑up pattern]{.underline} (vertically stacked
> straight‑line legs, figure 4) is used primarily for observing vertical
> profiles of cloud microphysical properties and atmospheric state
> parameters such as temperature and humidity. Useful radiative flux
> measurements are obtained if the legs are sufficiently long.
>
> The [spiral descent pattern]{.underline} will be performed at a rate
> of about 1 m s‑l and will be primarily used for making microphysical
> measurements (Heymsfield et al., 1990). The pattern is also
> well‑suited for deriving vertical motions from the observed horizontal
> winds (Gultepe et al., 1990). However, the accuracy of the radiative
> flux measurements may be compromised during such a descent. Similarly,
> radiative measurements taken during descent or ascent from one lever
> leg to the next in the step‑down/step‑up pattern will not be useful.
> The advantage of the spiral descent versus the step‑down/step‑up
> pattern is that the observed profiles of cloud microphysical
> properties are more representative of the conditions present in an
> atmospheric column at a particular time because the profiles are
> obtained in about 15 minutes rather than the time period of an hour or
> more required for step‑down/step‑up profiling.
>
> Each of these patterns may be flown in both an Eulerian and a
> Lagrangian manner (e.g., figure 5). In the [Eulerian
> mode,]{.underline} the orientation of the racetrack and
> step‑down/step‑up legs will be along the wind direction at cirrus
> altitude. The upwind end of each leg will generally coincide with the
> a location just upwind of the Hub (or R2) remote sensing site. Thus,
> the flight tracks of the *in situ* aircraft will cross the flight
> tracks of the remote sensing aircraft, often at a right angle. The
> Eulerian spiral descent will be flown over the Hub site. The diameter
> of the spiral is usually about 10 km. Data obtained from Eulerian
> sampling patterns are best suited for combination with satellite and
> surface‑based remote sensing data.
>
> In the [Lagrangian mode,]{.underline} the flight legs are also
> oriented along the wind. The patterns may be initiated in the vicinity
> (or upwind) of the Hub site but the upwind terminus of each successive
> leg is moved downwind to account for horizontal advection of the cloud
> by the wind (wind drift). Thus, the legs get progressively farther
> from where the pattern was initiated. Although the flight legs may
> remain within the view of the cross‑track scanning instruments on the
> remote sensing aircraft, all the flight tracks may not cross the
> remote sensing flight tracks. Similarly, coordination with the
> surface‑based observing sites is necessarily less. The Lagrangian
> spiral also drifts with the wind but can generally be confined to a
> small area close to the Hub site since each descent takes only about
> 15 minutes, i.e., the entire pattern can then be repeated beginning at
> the initial location**.** An entire step‑down pattern may take more
> than an hour and consequently drift some distance during that time (50
> m s-1 wind speeds yield a 180 km displacement in 1 hour).
>
> The lengths of flight legs for the racetrack and step‑down/step‑up
> patterns vary depending on the mission objectives, as described below,
> and the operating characteristics of the aircraft. Both the turboprop
> King Air and Citation can fly relatively short legs (20 km) and can
> perform spiral descent patterns. Based on experiences from IFO‑I, the
> King Air will often perform two or more of the above patterns in a
> given mission (below). This takes advantage of the operational
> flexibility of this platform and maximizes the overall applicability
> of the data obtained. Although this may at first seem to violate the
> maxim of simplicity, experience has shown that a set mufti‑mode
> pattern is operationally practical and yields significant scientific
> advantage.
>
> 4.3.3.3 Aircraft Missions
>
> Approximately fourteen (14) coordinated multi‑aircraft missions will
> be flown during the 25 days of FIRE Cirrus IFO‑II. \[A mission may
> involve more than one flight of a given aircraft.\] Several additional
> missions will be flown by the NCAR Sabreliner and King Air prior to
> the aircraft deployment to Kansas. *Other single‑aircraft missions may
> be conducted on a noninterference basis at the discretion of the
> Aircraft Principal Investigator.* Non‑interference means not only that
> such a mission will not be conducted during a coordinated mission but
> that it will not impact the operational capabilities for conducting a
> coordinated mission, e.g., on the same or following day. One of three
> basic multi‑aircraft mission plans will be executed on most aircraft
> experiment days. These coordinated missions are designed to satisfy
> the sampling and data requirements for achieving most of the
> scientific objectives of FIRE Phase II (section 3). Special missions
> focused on specific objectives requiring unique sampling strategies or
> conditions will also be performed.
>
> An estimate of the number of planned aircraft missions is given in
> table 12.
>
> [Pattern]{.underline} l
>
> Pattern 1 flights will consist of step‑ups and step‑downs with the
> NCAR King Air and Sabreliner in cirrus and altocumulus, in a direction
> along and against the prevailing wind. Depending on the available
> (planned) fuel time for the aircraft mission, arriving (departing)
> aircraft can perform step‑down (step‑up) patterns over the Hub site to
> calibrate the remote sensing instruments, such as the Raman lidar and
> surface radiometers.

Table 12 ‑ Summary of planned aircraft mission allocations for the FIRE
Cirrus IFO‑II. More than one fight (SL, KA) may be involved in a given
mission.

> ![](media/image18.wmf){width="6.805555555555555in"
> height="3.0694444444444446in"}
>
> [Pattern]{.underline} 2
>
> Pattern 2 is essentially a Eulerian mission (figures 5 and 6). It is
> the mission that will be executed for the three large‑scale case
> studies (intensive rawinsonde launches, section 3.3.4). The primary
> objectives of this mission are to characterize the time‑dependent
> cloud and radiative fields, cirrus cloud radiative and physical
> properties, and upper tropospheric water vapor and cloud water budgets
> within a fixed mesoscale region. The coordination of aircraft flight
> patterns and surface‑based remote sensing observations are maximized
> in this mission. Obtaining coincident satellite observations,
> especially by NOAA polar orbiting satellites, is a high priority in
> planning and executing this mission. Thus, besides supporting studies
> of cirrus cloud development (science objectives 1 and 2), this mission
> will also provide data well‑suited for satellite and surface‑based
> remote sensing studies (4, 6) and for quantifying the radiative impact
> of the clouds on the TOA, atmosphere and surface radiation budgets
> (5). The data will be useful, but not optimal, for characterizing
> relationships between cirrus cloud optical and physical properties
> (3).
>
> In Pattern 2, the ER‑2 will fly coordinated cross‑wind racetracks (150
> km in length) with one leg passing over the Hub site (midpoint). The
> Sabreliner and King Air will fly coordinated along‑the‑wind flight
> patterns over the Hub site, while the Citation will operate in
> coordination with the remote sensing aircraft and R2 remote sensing
> site. The Sabreliner will begin with a 50 km racetrack just above
> cloud top followed by a step‑down pattern (50 km legs at 2000\'
> intervals) to below the operating ceiling of the King Air (or cloud
> base). This pattern is then repeated. The King Air will begin with a
> Lagrangian spiral (initiated over or upwind of the Hub site) from its
> operating ceiling (or cloud top) to cloud base followed by a 30‑km
> racetrack just below cloud base. A step‑up pattern (20 km legs at
> 2000\' intervals) to operating ceiling (or cloud top) will then
> executed. This pattern is repeated one or more times. At the
> conclusion of the mission, an Eulerian spiral is performed over the
> Hub site. This King Air flight pattern was successfully executed in
> IFO‑I and is illustrated in figure 7. The Citation will perform 50‑km
> along‑the‑wind step‑up/step‑down profiles between cloud base and cloud
> top on a parallel heading. The flight track will intersect the flight
> track of the remote sensing aircraft and extend toward or over the R2
> remote sensing site.
>
> There is a potential conflict in that the Sabreliner and King Air are
> operating in close proximity. It is anticipated that such conflicts
> can be readily resolved in a safe manner. In a situation of two or
> more distinct cloud layers, the operating altitude ranges will not
> overlap, i.e., the King Air will work the longer cirrus layer and the
> Sabreliner will work the upper cloud layer(s). In this situation,
> which will likely occur during some missions, an additional racetrack
> pattern must be flown at cloud top (King Air) and cloud base
> (Sabreliner) of the respective cloud layers. The Citation will work
> both cloud layers. Furthermore, a capability for some adjustment of
> aircraft flight levers based on concurrent surface‑based observations
> (lidar and radar) may be desirable.

[Pattern 3]{.underline}

> Pattern 3 is primarily a Lagrangian mission. The primary objectives
> for this mission are to characterize the radiative budgets and
> broadband radiative properties of individual cirrus clouds in
> relationship to the horizontal and vertical structure of the cloud
> (science objective 2), to characterize the microphysical development
> of the cloud (2). Thus, this mission is focused on some of the more
> problematic aspects of understanding cirrus cloud development in
> support of cloud‑scale modeling studies and parameterization
> development (1). The data will be directly applicable for
> satellite‑based studies (4) and for characterizing the radiative
> impacts of cirrus (5). Coordination with the surface sites is highly
> desirable but will be necessarily somewhat limited in the case of the
> *in situ* platforms. Nonetheless, the data will provide useful
> information for improving the utilization of surface‑based remote
> sensing observations for quantitative
>
> quantitative studies of cirrus clouds (6).
>
> In Pattern 3, the ER‑2 will operate in the same manner as in a Pattern
> 2, i.e., cross‑wind racetracks over the Hub site. The *in situ*
> aircraft will conduct along‑the‑wind Lagrangian flight patterns
> (drifting with the wind) on specific advecting cloud targets.
>
> **FIRE Cirrus IFO‑II**
>
> **Typical NCAR King Air Flight Pattern**
>
> **Eulerian Mission (Pattern 2)**

![](media/image19.wmf){width="7.083333333333333in"
height="7.055555555555555in"}

Figure 7 ‑ Schematic of FIRE Cirrus IFO‑II Eulerian Mission, Pattern 2
(altitude vs time) for NCAR King Air *(in situ).* The entire pattern is
flown over the Hub site. Time permitting, the A‑B sequence is repeated.

> The Sabreliner will fly 70 to 100‑km racetracks just above cloud top,
> and at 2000\' and 4000\' below cloud top. The King Air will fly a
> Lagrangian spiral from its operating ceiling (or cloud top) to cloud
> base followed by 70 to 100‑km racetracks just below cloud base and at
> 2000\' and 4000\' above cloud base. These patterns should cross the
> flight track of the remote sensing aircraft and overfly one of the
> remote sensing sites during portions of the mission. Ideally, the
> Lagrangian spiral would be performed over the Hub site. In this
> mission, the Sabreliner and King Air may work on the same cloud target
> or in an independent fashion on separate targets. The Citation will
> perform along‑the‑wind Lagrangian step‑down/step‑up microphysical
> profiling below the Sabreliner (to cloud base) or above the King Air
> (to cloud top) when they are working separate targets or over the Hub
> or R2 remote sensing sites (cloud top to cloud base) when they are
> working the same target.
>
> [Pattern]{.underline} 4
>
> Pattern 4 is strongly focused on two important objectives. It provides
> observations essential for quantifying the capabilities and
> limitations of satellite‑based cirrus cloud retrievals (science
> objective 4) and for characterizing relationships between cirrus cloud
> optical and physical properties (3). At least three such missions are
> planned. Two will be conducted over the Gulf of Mexico providing a
> uniform and weakly reflecting background to simplify analysis of the
> radiative observations. The missions will be performed during overpass
> of Landsat and/or one of the NOAA polar orbiting satellites. Two
> aircraft will be deployed for these missions, the ER‑2 and one *in
> situ* platform. The Sabreliner is best suited in terms of
> instrumentation, specifically the small ice particle probe, ice
> crystal collector (crystal habit), and scanning multispectral
> radiometer. The Citation might be better suited in terms of range and
> altitude capability but the potential lack of the small ice particle
> probe is very limiting. The ER‑2 will fly racetrack patterns
> perpendicular to the solar plane. The *in situ* platform will fly a
> 50‑km step-down/step‑up vertical profiling pattern. Although a flight
> track directly under and along the ER2 flight track has strong
> conceptual appeal, a number of factors make this choice suspect.
> Absolute coincidence is difficult to achieve because of uncertainty in
> navigation and differences in aircraft flight speeds. Also, when the
> flight track is across‑the‑wind (as will probably be the case), the
> presence of even moderate vertical wind shear greatly complicates the
> analysis in that it is difficult to establish whether data taken at
> one lever is representative of conditions when another lever is being
> sampled, especially if the clouds are deep and horizontally
> inhomogeneous as is often the case for cirrus. Thus, an
> along‑the‑wind, Lagrangian crossing pattern is more suitable with
> respect to providing coincident measurements of a target region within
> the view of the cross‑track scanning ER‑2 instruments. The location of
> the aircraft patterns will be over one or more buoys located at 25.9N
> and 85.9W, 89.7W, and 93.6W. Since the Sabreliner will have to refuel
> in order to perform the Gulf of Mexico mission, the Sabreliner may
> plan to conduct two such missions in successive days. This will
> require the Sabreliner to remain overnight at San Antonio.
>
> The third satellite remote sensing mission will be a nighttime mission
> involving both remote sensing aircraft and one or more of the *in
> situ* platforms. It will be conducted in conjunction with the
> nighttime overpass of the NOAA polar orbiter (\~0230 LST). The purpose
> is to provide a severe test case for satellite cirrus cloud retrieval
> techniques in which the surface and atmospheric boundary layer present
> a cold background (nocturnal cooling). This situation is significantly
> more challenging than simply considering only infrared channels during
> the day when the background contrast is much higher. Since it is at
> night, the sampling patterns will be oriented with respect to the wind
> at cirrus level and the mission will be conducted the same as a
> Pattern 3 mission. If feasible, more than one such mission may be
> flown.
>
> [Special Missions]{.underline}
>
> Three special missions are planned.

\(a\) The [first special mission]{.underline} is to support SPECTRE. Due
to its radiometric

instrumentation (especially the HIS), the ER‑2 is required. One of the
*in situ*

platforms is also desired. The Sabreliner is best suited for this
mission given its

higher operating ceiling and, thus, the capability to observe upper
tropospheric

moisture content as well as radiative fluxes and radiance fields. The
mission

would be conducted in essentially the same manner as a Pattern 2 (but
with

smaller racetracks or spirals) with the *in situ* aircraft profiling the
upper

troposphere just downwind of the Hub site (Eulerian along‑the‑wind
racetracks)

and the ER‑2 flying crosswind racetracks just *downwind* of the Hub
site. At least

one such mission will be flown, probably at night during either clear
sky or

cloudy conditions.

\(b\) The [second special mission]{.underline} is designed to
investigate potential improvements in

our ability to utilize data from the 6.7 gm water vapor channel on the
GOES and

the three water vapor HIRS‑2 channels on the operational polar orbiter
for

quantitatively characterizing upper tropospheric water vapor fields.
Imagery from

the GOES 6.7 \~m channel has long proven very useful to forecasters but
has

proven very difficult to quantify and incorporate into operational or
research

models. In essence, the detected radiances depend on the temperature of
the

upper 2 mm of precipitable water vapor (McGuirk et al., 1987; Blackwell
et al.,

1988). Thus, the signal does not depend on moisture alone. In addition,
clouds

also affect the detected radiances. Similar problems have precluded use
of HIRS

water vapor measurements in operational forecast models due to the
resulting

uncertainties. The absence of any accurate independent observations of
upper

tropospheric water vapor has precluded attempts to unravel the different
effects.

> The new capability for making accurate *in situ* water vapor
> measurements in the upper troposphere (airborne cryogenic frost point
> hygrometer) and, potentially, upper tropospheric water vapor
> measurements from the surface (Raman lidar) provides, for the first
> time, a means to investigate the applicability of satellite
> observations for quantitatively characterizing the three dimensional
> structure of upper tropospheric water vapor.
>
> The Sabreliner is best suited for this mission. The flight pattern
> will consist of 300‑km legs flown at three levers (Lagrangian
> step‑down/step‑up) either up or clown the anticipated gradient of
> water vapor under generally clear conditions. The wind drift should be
> taken as the mean 400 mb lever wind. The nominal altitude of the legs
> will be at 17,000\', 23,000\', and 30,000\'. The flight tracks should
> extend over the surface Raman lidar (Hub site) and the mission should
> coincide with release of rawinsondes at NWS and the special CLASS
> stations (section 4.3.4) and GOES observations (half‑hourly) using the
> 6.7 gm charnel (section 4.3.1). Coincidence with an overpass of the
> NOAA polar orbiting satellite is [essential]{.underline}. Maximizing
> the utility of the Raman lidar data would require a nighttime mission,
> e.g., 0230 NOAA overpass. The potential value of the mission to the
> objectives of FIRE (section 3.2) and more generally to the issues of
> observation and prediction of upper tropospheric cloudiness and
> climate change dictate that at least two such missions be flown. One
> could be conducted in conjunction with the SPECTRE mission described
> above.
>
> \(c\) [The third special mission]{.underline} is to intercalibrate the
> ER‑2, Sabreliner, and satellite
>
> solar reflectance channels. The ER‑2 MAS radiometer will be used as a
> transfer
>
> standard for the relative calibration of satellite and aircraft
> spectral radiometers.
>
> This requires coordinated ER‑2/Sabreliner intercalibration flights for
> nadir view
>
> above clouds, and for coordinated ER‑2/satellite intercalibration
> flights where the
>
> ER‑2 flight track is chosen to provide scanning MAS imager data at the
> same
>
> time, same location, same viewing zenith angle, and same viewing
> azimuth angle
>
> as the satellite at the time of the satellite overpass. Satellite
> overpass predictions
>
> and control of the ER‑2 flight track during overpass (plus or minus 5
> minutes)
>
> should allow matching view angles within about 2‑5•.
>
> This calibration strategy requires coordination of satellite/aircraft
> and aircraft/aircraft flights during the IFO. The ER‑2/Sabreliner and
> ER‑2/satellite cases can be obtained as part of other flight missions.
> The ER‑2/satellite intercalibration only requires about 10 minutes of
> ER‑2 time during the satellite overpass. Intercalibration data taken
> over optically thick cloud targets is preferred in order to maximize
> reflected signal, to minimize the effect of a strong spectral
> variation of reflectance for land surfaces, and to minimize anisotropy
> of reflected radiation. Intercalibration is also preferred for
> satellite viewing zenith angles within l5° of nadir, but up to 30• is
> acceptable. Two of every nine days will meet the 15• viewing zenith
> criterion, while 4 of every nine days will meet the 30• criterion.
> Spatial location of satellite and aircraft pixels will be obtained by
> maximizing the spatial correlation of the satellite and ER‑2 MAS
> radiance images, thereby achieving relative navigation accuracies of
> approximately 1 pixel in the radiometer image with the largest field
> of view (usually the satellite image, except for Landsat). Information
> required to register the images is cloud height from the ER‑2 lidar (a
> single lever cloud case is highly desirable but not essential) and
> horizontal vector winds at the cloud lever. An example of this
> navigation procedure as used in the first FIRE field experiment can be
> found in Wielicki et al., 1990. Once the two images are navigated to a
> common geometry, intercalibration is performed using a strip of the
> ER‑2 radiometer data along the aircraft track (approximately plus or
> minus 3 minutes of the overpass, resulting in 200 m/sec x 360 sec = 72
> km of data) at an aircraft viewing zenith angle and azimuth angle
> which matches the satellite data. A schematic is given in figure 8.
> The 3‑minute time limitation will minimize cloud advection errors.
> Nominal cloud motion will be accounted for using aircraft or wind
> profiler data. At 20 m/sec, the cloud will move 3.6 km in 3 minutes. A
> window of aircraft ER‑2 data 5 minutes before and after the nominal
> satellite overpass is required to allow for uncertainty in the
> overpass time of about 1 minute.
>
> Satellite/ER‑2 intercalibrations are desired once near the beginning
> of the experiment and once near the end of the experiment for each
> satellite, to verify stability of the radiometers and the calibration
> method. This would require a total of 7\*2\*20 = 280 minutes or about
> 4 1/2 hours of ER‑2 flight time over the entire experiment. Since the
> polar orbiting satellite \"round tracks are approximately north/south,
> the desired aircraft flight tracks will also be approximately
> north/south, so that the intercalibration portion of each ER‑2 flight
> should also be reasonably close to a track perpendicular to a wind
> direction, as required for other experiment objectives. If the GOES‑7
> satellite is positioned at 98• West longitude, then an east/west
> flight track (scan plane north/south) will give alignment with the
> GOES viewing azimuth angle.
>
> A summary of the aircraft and satellite spectral solar radiometers is
> given in table 11. Final solar reflectance bands for the MAS
> spectrometer will be selected to optimize intercalibration of the
> current satellite and aircraft sensors as well as to preview
> capabilities of the future EOS MODIS‑N instrument. Suggested
>
> ![](media/image20.wmf){width="7.986111111111111in"
> height="9.569444444444445in"}
>
> Table 11 ‑ Summary of spectral channels for the ER‑2 and satellite
> instruments.
>
> ![](media/image21.wmf){width="7.0in" height="3.736111111111111in"}
>
> Note 1: All channels spectral bandpasses specified as 1/2 power
> spectral response.

Note 2: Nominal overpass times are given as equator crossing time.
Actual local time will vary within 1 hour of the nominal time.
Predictions of actual overpass time on each experiment day will be made
available approximately 24 weeks before the experiment.

> bandpasses for the remaining four MAS channels are given in table 11,
> along with spectral bandpasses of satellite radiometers.
>
> 4.3.4 Rawinsonde Observations
>
> Acquisition of rawinsonde and other surface‑based remote sounding data
> will be increased substantially for FIRE Cirrus IFO‑II in comparison
> to IFO‑I. These data are absolutely crucial to the success of efforts
> to model cirrus cloud development on the large scale (science
> objective 1, section 3) and to characterize cirrus cloud development
> at smaller scales using detailed cloud models and analysis (1 and 2).
> The data will be used to define atmospheric conditions on scales
> ranging from the synoptic scale to the scale of individual mesoscale
> cloud features. Moreover, accurate knowledge of atmospheric
> temperature structure is essential for analysis and modeling of
> infrared radiative transfer in cirrus clouds (3, 4 and 6), for
> inferring cirrus cloud properties from satellite observations (4), for
> assessing the effects of cirrus clouds on the surface and TOA
> radiation budgets (5), for analysis and modeling of atmospheric
> radiative transfer (5), and for analysis of surface‑based remote
> sensing observations of cirrus clouds (6).
>
> Enhancements to routine NWS rawinsonde operations are required over a
> large area encompassing the most of the continental United States
> (figure 9), excluding only the eastern region, in support of the
> large‑scale modeling efforts. *Three intensive case studies are
> planned at this scale. Each case will be 36 hours in duration.* The
> data will be used directly for model initialization and verification
> and as input to model‑based FDDA analysis studies, and indirectly for
> deriving cloud fields from satellite observations over a wide area
> (model verification). For these cases, 6‑hourly data are required over
> the large area (Type A and Type B stations; table 13 and appendix H)
> while 3‑hourly soundings are required over a smaller region (Type A
> stations only) encompassing the south‑central U.S. during the lest 12
> hours (i.e., 6‑hourly for the first 24 hours). Participation of
> additional stations (13 more Type B stations) along the northern tier
> of the U. S. (8) and in northern Mexico (5) is highly desirable
> (figure 9). Understanding the development of cirrus clouds and
> associated dynamic and thermodynamic structure requires enhanced
> temporal coverage over a large area given the wind speeds prevalent at
> cirrus altitude (sub‑tropical jet stream), especially for considering
> the nature and characteristics of mesoscale dynamic disturbances at
> cirrus altitude (e.g., Starr and Wylie, 1990; Stevens and Ciesielski,
> 1988). In addition, the lack of moisture information at levers above
> the ‑40•C isotherm may be compensated by additional temporal coverage
> in a FDDA analysis.
>
> NWS rawinsonde stations (Type A stations) will also operate in an
> enhanced mode (a supplemental mid‑day sounding at 1800 UTC) over the
> south‑central U.S. (figure 9) on most other operational days (aircraft
> operations) during the experiment (a total of 10 days). These data
> will be used to characterize cirrus cloud development and to analyze
> cirrus cloud conditions over the region.

FIRE will also field five CLASS‑type rawinsonde stations (table 14).
Four of these systems will be deployed in an arrangement designed to
facilitate combination with NWS and FIRE wind profiler data to en able a
complete analysis of the dynamic and thermodynamic development over
triangular areas defined by three NWS wind profiler stations (figure 3).
These data support the application of small‑scale cloud models used to
develop cirrus parameterizations for large‑scale models. The CLASS‑type
systems make measurements of atmospheric water vapor content to a higher
lever than standard NWS sondes. Although the upper limit is not well
established, the observations are useful to at least the ‑50•C lever
(Starr and Wylie, 1990), which is more than 1 km higher than for NWS
sondes (to ‑4°C). This is often sufficient to include the longer portion
of cirrus clouds. The rawinsonde observations will also directly support
analysis and modeling of radiative processes and remote sensing
observations (satellite, airborne and ground‑based). These studies are
highly focused in the area of the remote sounding sites where the CLASS
sites will be located. These four stations follow the same launch
schedules as the Type A.

![](media/image22.wmf){width="7.430555555555555in"
height="9.430555555555555in"}

Table 13. Modes of operation of NWS rawinsonde stations in support of
Cirrus IFO‑II. A11 times are UTC. (See figure 9).

![](media/image23.wmf){width="7.152777777777778in" height="4.625in"}

NWS rawinsonde stations. However, the station at the Hub site will also
provide on demand support for remote sensing activities at the request
of the mission or lead scientist (noninterference basis).

> A fifth CLASS‑type rawinsonde station will also be located at the Hub
> site to support the SRB activities. This station will provide routing
> soundings on all days during overpasses (ascending and descending
> orbits) of the two operational NOAA polar orbiting satellites (4
> soundings per day).
>
> 4.4 Operational Forecasting

A capability to adequately forecast cloud and weather conditions for
operational planning and daily operations is absolutely essential. Two
operational decisions involve appreciable lead times and are
particularly forecast sensitive. The NASA ER‑2, that will base in San
Antonio, requires a two‑hour lead time to prepare the pilot. This and
the transit time from San Antonio to the FIRE operations area result in
a need to schedule take‑off more than four hours in advance. Once

> Table 14 ‑ Modes of operation of CLASS‑type rawinsonde stations in
> support of FIRE Phase II Cirrus Intensive Field Observations. All
> times are UTC. There will be two (2) stations located at the Hub site.
> One will perform the routine launches while the other will conduct the
> enhanced, intensive, and special launches. There will be three (3)
> additional CLASS‑type stations conducting enhanced and intensive
> soundings (see figure 1).
>
> ![](media/image24.wmf){width="7.125in" height="4.388888888888889in"}
>
> prepared, take‑off can be delayed but delays cannot be excessive.
> Thus, final decisions to commit the ER‑2 to flight require a firm 4
> *to 10‑hour forecast.* There are also requirements with respect to
> surface weather conditions expected for landing (a forecast for
> excessive winds will cause a mission to be scrubbed). The expectation
> of more favorable surface wind conditions was a prime reason for
> basing the ER‑2 in San Antonio rather than Kansas. This latter
> forecast‑decision will be the responsibility of flight support
> personnel in San Antonio and not FIRE.
>
> The second forecast‑sensitive decision is activating the large‑scale
> NWS rawinsonde network for intensive operations (section 4.3.4) in
> support of each of three planned large‑scale experiment events. A
> commitment to launch the supplemental 1800 UTC midday sondes (43
> stations) would be required by about 1200 UTC that morning. A
> commitment for the late‑night 0600 UTC launch would be needed by early
> afternoon (\~1800 UTC). A commitment for full intensive mode launches
> (3‑hourly from 1200 UTC to 0000 UTC at 15 stations and a supplemental
> 1800 UTC launch at 28 stations) would be required before 0000 UTC.
> Obviously, operations could be cancelled in mid‑event if conditions do
> not proceed as forecast. However, this is highly undesirable as
> limited resources would be depleted. Thus, a good *36‑hour forecast*
> of expected conditions, particularly cirrus cloudiness and surface
> weather, is crucial. Experience from IFO‑I shows that this is a very
> challenging, but achievable, requirement. A conservative forecasting
> approach and selection of a large‑scale target system, such as
> extended cirrus associated with the subtropical jet stream, are
> prudent given that there are 25 experiment days in which to execute
> these three experiments.
>
> Lastly, forecasting support is also necessary for daily operations. A
> good *12 to 24‑hour forecast is* needed each evening to plan
> operations for the next day. This is also important for scheduling
> maintenance and calibration activities and ensuring high performance
> of project personnel over the entire experiment given the limited
> personnel (some clown days will be required). A longer range outlook
> is also essential, since conduct of a mission may impact the ability
> to conduct another mission of the following day (some missions over
> the Gulf of Mexico and at least one night mission are planned). Except
> for the ER‑2 (see above), the research aircraft are generally quite
> flexible. Operations may be delayed until conditions improve with
> little real consequence. Thus, a firm 0 to 12‑hour forecast at 1200
> UTC will generally be adequate. This will also be satisfactory for
> committing to enhanced NWS rawinsonde launches (a supplemental 1800
> UTC sonde at 15 stations on \~10 days).
>
> FIRE will be responsible for providing forecasting support. The
> following information will be available at the forecast room in the
> operations center:
>
> • NWS rawinsonde observations,
>
> • NMC analysis products (weather maps),
>
> • NMC forecast‑model output data base (including all upper
> tropospheric levers),
>
> and
>
> • GOES imagery (full resolution visible, infrared and water vapor
> channels).
>
> The satellite imagery must be available in video time‑sequence format
> and all information must be current. A dedicated priority link to the
> Man‑Interactive Data Acquisition System (McIDAS) at the University of
> Wisconsin ‑ Madison will provide near‑real-time access to this
> information in a highly usable format.
>
> The field observations also provide an important source of information
> for short‑term forecasting as is often required just prior to a
> mission. Near‑real-time access to the following data is highly
> desirable:
>
> • lidar observations (especially the scanning VIL lidar),
>
> • rawinsonde soundings (GLASS),
>
> • Raman lidar observations of mid‑ and upper tropospheric water vapor,
> and
>
> • wind profiler observations.
>
> A capability to electronically access and display this information
> would be ideal. A hardcopy capability is also desirable. Some means to
> transmit information, especially satellite and lidar images to
> aircrews prior to take‑off and also *during* flight, would enhance
> operations. In addition, since observations from the remote‑sensing
> sites are essential for the pre‑mission briefing and final planning
> decisions, this will require that selected investigators have
> sufficient personnel to operate their instruments in the early morning
> (prior to aircraft operations) while the principal investigators are
> involved in mission planning. Good communications, including data
> transmittal and display, between the Hub and VIL sites and the
> \'briefing center\' would also be essential.
>
> 5.0 OPERATIONS
>
> 5.1 Functional Organization
>
> The functional organization for implementing the Cirrus IFO‑II is
> shown in figure 10. Names, addresses, and phone numbers of the
> incumbents are provided in appendix C. A brief description of
> incumbent responsibilities follows:
>
> [Program Manager]{.underline} ‑ Responsible for overall program
> guidance, review, and selection of projects and project elements, and
> funding.
>
> [Project Manager]{.underline} ‑ Responsible for the overall
> management, coordination, and reporting of the project activities.
>
> [Agency Representatives]{.underline} ‑ Responsible for assisting the
> Project Manager in selection of projects, project elements, and agency
> funding and support.
>
> [Cirrus Working Group]{.underline} ‑ Responsible for defining the
> goals of the Cirrus IFO‑II and monitoring the progress of individual
> and collective research.
>
> [Lead Mission Scientist]{.underline} ‑ Dr. David Starr has been
> appointed as the Lead Mission Scientist for the Cirrus IFO‑II. The
> Lead Mission Scientist will be the scientific spokesperson for the
> Cirrus field experiment. He will coordinate the planning and
> implementation for the science objectives, conduct planning and
> debriefing sessions, and be the chief representative of and arbitrator
> for the participants in the field experiment.
>
> [Mission Selection Team]{.underline} ‑ The Mission Selection Team
> (MST) will be comprised of participating FST scientists, platform and
> instrument representatives, and FIRE project personnel; it will be
> chaired by the Lead Mission Scientist. The MST will accept the
> following responsibilities:
>
> i\. solicit and represent ideas of other FIRE scientists in
> operations, decisions, and
>
> scheduling.
>
> ii\. review on a daily basis the candidate missions and plan the
> detailed operations
>
> and scheduling of all FIRE platforms for the following day, including
> a prime
>
> mission plan and an alternate mission plan.
>
> iii\. select on a daily basis a Mission Scientist (MS) and a Deputy
> Mission Scientist
>
> (DMS) to plan and carry out operations selected by the MST.
>
> iv\. assemble forecast information for use in daily operations
> planning. \*
>
> v\. prepare a post mission summary of each day\'s operations including
> an evaluation
>
> of the success of the operations. This daily summary will be made
> available to
>
> the FIRE Project Office and become a part of the FIRE data archive.
>
> vi\. maintain up‑to‑date experiment accomplishment records for use in
> daily
>
> operations planning. \*
>
> vii\. maintain current statue reports on all data gathering components
> throughout the experiment. \*
>
> \* assisted by the FIRE Project Office.
>
> All deliberations of the MST will be open, and in the absence of a
> clear concerns among its members, the chairman will assume
> responsibility for making operations decisions.
>
> On issues concerning specific platforms such as aircraft or special
> rawinsonde accents, an appropriate spokesperson from the contributing
> organization will be given the opportunity to participate on the MST.
>
> [Mission Scientist]{.underline} ‑ A Mission Scientist (MS) will be
> identified on a daily basis by the MST at the same time the following
> day\'s mission is selected. A Mission Scientist must have an overall
> grasp of the scientific objectives of FIRE as well as an appreciation
> of operational constraints of the various platforms and personnel. A
> Deputy Mission Scientist (DMS) will also be selected by the MST to
> assist the MS in all phases of the mission, including monitoring the
> progression of the meteorology situation throughout the day. The MS
> will be in charge of the detailed planning of the following day\'s
> operations and the execution of that plan. He will be responsible for
> making any real time decisions required during the execution of the
> plan. He will prepare a post mission summary of each day\'s operations
> including an evaluation of the success of the operations. This daily
> summary will be made available to the FIRE Project Office and the MST
> and become a part of the FIRE data archive.
>
> The Mission Scientist will be selected from a pool of lay FST
> researchers according to the scientific objectives to be addressed in
> the upcoming mission and the scientific background of the individual.
> Ideally, the Mission Scientist would be the previous
>
> ![](media/image25.wmf){width="6.736111111111111in"
> height="9.38888888888889in"}
>
> mission\'s DMS so as to provide continuity between missions and
> familiarity with on‑going meteorology conditions and forecasts.
>
> A single operations center will be established and normally manned
> each day. The MS will be the central point of contact and coordination
> between the principal investigators (PIs) and project operations
> personnel.
>
> The responsibilities and functions of the MS are:
>
> i\. Establish, post, and maintain a daily operations schedule; \*
>
> ii . Establish an active duty roster for operations and PI personnel;
> \*
>
> iii\. Maintain a daily log on mission statue and activities; \*
>
> iv\. Work with the Aircraft Coordinators to allow proper scheduling of
> crews for flight operations and aircraft access;
>
> v\. Work with the Field Site Coordinators to allow proper scheduling
> of surface
>
> observations; and
>
> vi\. Prepare and post a daily post‑mission summary. \*
>
> \* assisted by the FIRE Project Office
>
> [Mission Meteorologist]{.underline} ‑ The Mission Meteorologist will
> be responsible for meteorological forecasting and assisting in
> planning for aircraft flight missions. He is also responsible for the
> collection, distribution, and archiving of meteorological data
> products required to support the science investigators and mission
> operations.
>
> [Operations Manager]{.underline} ‑ The Operations Manager will have
> overall responsibility for organizing, scheduling, and coordinating
> the support of the field operations. He is responsible for the
> preparation of mission plans and determining special support
> requirements and operational procedures. He is also responsible for
> coordinating the logistical requirements of measurement platforms and
> instruments for resources, testing, and integration for all field
> measurements. Lastly, he is responsible for the setup, manning, and
> daily operation of the operations center, including the maintaining of
> the mission resources, statue, and activity log.
>
> [Platform/Instrument Representative]{.underline} ‑ To ensure proper
> exchange of information on schedules, meetings, and instrument statue,
> each PI is responsible for designating a single person each day as the
> spokesperson for his experiment. The designated person will be the
> contact point for the MS. This person will attend scheduled meetings,
> provide status on his experiment, participate in flight planning, and
> will be responsible for informing his co‑workers of schedule changes.
>
> [Aircraft Coordinators]{.underline} ‑ The Aircraft Coordinators will
> be responsible for the in‑flight coordination between the science
> investigators and the flight crew and the overall integration,
> testing, and operation of experiments aboard their respective
> aircraft, including \"round support operations.
>
> [Field Site Coordinators]{.underline} ‑ The Field Site Coordinators
> will have primary responsibility for coordinating complementary
> \"round measurement activities and overall integration, testing, and
> operation of experiments of their respective sites.
>
> [Data Manager]{.underline} ‑ The Data Manager will be responsible for
> coordinating the types, scope, and quantity of data collected during
> the field experiment and its archiving.
>
> [Satellite Coordinator]{.underline} ‑ The Satellite Coordinator will
> be responsible for providing information on the periods and locations
> of satellite observation within the Cirrus IFO‑II area. He is
> responsible for determining that the appropriate satellite
> observations are being collected, archived, and made available to the
> Cirrus Working Group.
>
> [Project Coordinator]{.underline} ‑ The project coordinator will
> provide administrative and logistical support to the FIRE Project
> Office, including reimbursement support in the planning, coordinating,
> and conducting of the Cirrus IFO‑II mission.
>
> 5.2 Aircraft Integration and Unloading Sites
>
> 5.2. 1 ER‑2
>
> Instrument integration and unloading of the ER‑2 will occur at NASA
> Ames Research Center, Moffett Field, California.
>
> 5.2.2 King Air and Sabreliner
>
> Instrument integration and unloading of the King Air and Sabreliner
> will occur at NCAR, Boulder, CO. In addition, several check out and
> research calibration flights will be performed before the aircraft
> deploy to Coffeyville, Kansas.
>
> 5.2.3 Citation
>
> Instrument integration and unloading of the Citation will occur at the
> University of North Dakota.
>
> 5.3 Logistics
>
> 5.3.1 Pre‑Mission Site Inspection
>
> Approximately six months and two weeks prior to the stars of the
> Cirrus IFO‑II, an
>
> advance party consisting of FIRE Project and ST Systems Corporation
> (STX) employees will arrive in Kansas to prepare for arrival of the
> main group. The advance party will perform the following functions:
>
> i\. Establish suitable accommodations and have available on schedule;
>
> ii\. Establish Operations/Forecast Center location.
>
> iii\. Establish Aircraft Base location.
>
> iv\. Check statue of advance equipment and supply shipments;
>
> v\. Ensure availability of supplies to be obtained in Kansas;
>
> vi\. Set up support system (e.g., communications, meteorological) if
> required;
>
> vii\. Ensure availability of support lab space;
>
> viii\. Ensure transportation available on schedule;
>
> ix\. Ensure aircraft support on schedule; and
>
> x\. Receive additional equipment shipments.
>
> 5.3.2 Equipment Shipment
>
> Arrangements and maintaining budget for the shipment of mission
> related equipment and supplies to and from Kansas is the
> responsibility of each principal investigator. To allow for delays,
> clearances, and \"red tape\", shipments should be scheduled to arrive
> in Kansas no later than November 6, 1991, if possible.
>
> 5.3.3 Personnel Deployment
>
> Arrangements and maintaining budget for the deployment of personnel to
> and from the field sites in Kansas are the responsibility of each
> principal investigator. In general, personnel associated with
> ground‑based measurements should begin set‑up of equipment 7 days
> prior to the first scheduled aircraft mission.
>
> 5.3.4 Accommodations
>
> Lodging at Coffeyville, Kansas, will be at either the Apple Tree Inn,
> 900 East 11th Street, Coffeyville, Kansas (316‑251‑0002), or the Best
> Western Fountain Plaza Inn, 104 West 11th Street, Coffeyville, Kansas
> (316‑251‑2250), as coordinated by STX. See appendix E for additional
> relevant information.
>
> 5.4 Location of Instruments, Aircraft, and Mission Operations at
> Coffeyville Airport
>
> The location of the instruments, aircraft, and Mission Operations at
> the Coffeyville Airport are shown in figure 11 and table 15.
>
> 5.5 Communications and Data Transmission
>
> The FIRE Project Office will establish (as permitted by the FCC) a
> communications network to provide clear voice and data transmission
> channels between the Operations Center and the various components of
> the expedition. This network will permit real‑time coordination and
> data display during the field operations. The following information
> lists the telephone, radio, satellite, and Internet links:
>
> [Radiolinks]{.underline}:
>
> i\. NCAR King Air ‑ NCAR Sabreliner ‑ UND Citation ‑ NASA ER ‑ 2
>
> ii\. Operations Center (Hub) ‑ NCAR King Air ‑ NCAR Sabreliner ‑ UND
> Citation ‑ NASA ER ‑ 2 (if possible)
>
> iii\. VIL (Rla) (?) ‑ NCAR King Air ‑ NCAR Sabreliner ‑ UND Citation

iv\. ER‑2 ‑ Airbase (San Antonio, Texas)

> ![](media/image26.wmf){width="7.930555555555555in" height="10.0in"}
>
> Table 15 ‑ Location of instruments, aircraft, and Mission Operations
>
> ![](media/image27.wmf){width="7.694444444444445in"
> height="6.972222222222222in"}
>
> v\. R2 (?) ‑ NCAR King Air ‑ NCAR Sabreliner ‑ UND Citation
>
> i, ii, and iv are absolutely essential
>
> [Phone Links]{.underline}:
>
> i\. Operations Center ‑ R2 (Parsons)
>
> ii\. Operations Center‑ Rla (TBD)
>
> iii\. Operations Center ‑ R3 (TBD) ?
>
> iv\. Operations Center ‑ ER‑2 Airbase (San Antonio, Texas)
>
> v\. Operations Center‑ CLASS Rawinsonde Sites (TBD)
>
> vi\. Operations Center‑ NWS Sites
>
> vii\. Operations Center ‑ Agencies responsible for operations of
> various satellites, especially GOES.
>
> viii\. Operations Center ‑ FAA authorities in Kansas City for flight
> plan approval.
>
> ix\. Operations Center ‑ T1 internet line for data transfer
>
> x\. Operations Center ‑ HSRL lidar for display of real time lidar data
>
> xi\. Operations Center ‑ NSI for monitoring of T1 line
>
> A voice phone link with guaranteed access must be in place in each of
> the above cases. Special attention will probably be required to assure
> this is true for link (vi and vii). Links (i), (iv), (v), (ix), (x),
> (xi), and (xii) will also serve for data transmission.
>
> [Satellite Links]{.underline}
>
> i\. Operations Center ‑ reception of direct GOES digital data by
> Digital Weather Imaging Processing Systems (DWIPS)
>
> ii\. Operations Center ‑ reception of direct AVHRR digital data by
> Naval Postgraduate
>
> School\'s satellite acquisition system.
>
> Table 16 and figure 12 show the communications network. Table 17 gives
> the type of equipment, frequencies, transmitted power, and functions
> for the radio communications.

![](media/image28.wmf){width="7.152777777777778in"
height="8.680555555555555in"}

![](media/image29.wmf){width="7.638888888888889in" height="7.75in"}

Table 17 - Radio communications network.

**Location** **Radio Frequency, Transmitted** **Function**

**MHz** **Power, watts**

Operations Center FM 165.6625 3 voice link to aircraft

NASA ER-2 VHF 118-135.95 10 voice link to aircraft

UHF 225.000-399.975 25 voice link to San Antonio

NCAR Sabreliner VHF 118 - 135.95 10 voice link to Operations

FM 165.6625 3 Center, VIL (Rla), R2, and aircraft

NCAR King Air VHF 118 - 135.95 10 voice link to Operations

FM 165.6625 3 Center, VIL (RI a), R2, and

aircraft

UND Citation VHF 118-135.95 10 voice link to Operations

FM 165.6625 3 Center, VIL (RI a), R2, and

aircraft

San Antonio TBD TBD TBD voice link to ER-2

VIL (RI a) TBD TBD TBD listen link to Center/aircraft

R2 TBD TBD TBD listen link to Center/aircraft

Protocol and schedules will be established as required to meet
expedition operational needs. In general, on flight days all radios will
be tested and manned throughout the flight period. A person or persons
will be designated as the responsible party for communication on each
radio. On non-flight days the Operations Center\'s radios will be manned
on request.

5.6 Electronic Interference

> Another concern is the potential for *electronic interference* among
> various active and passive sensing systems, including those borne on
> aircraft, balloons, and communication equipment. In particular,
> potential interference problems between wind profilers and rawinsonde
> systems operating near 400 MHz and between wind profilers and aircraft
> operations need to be understood and resolved, if possible. Efforts
> will be initiated to investigate this issue and to recommend possible
> solutions which may include altering the location of specific problem
> systems. In this vein, the location and operation of the RASS system
> will minimize the potential negative impacts of acoustic pulses
> (noise) on project personnel.
>
> 5.7 Briefing, Planning, and Coordination Meetings
>
> 5.7.1 Mission Selection Team Meeting
>
> Nominally, daily meetings will be held by the MST to prepare candidate
> missions for the following day\'s operations. Prime and alternate
> experiment plans are to be developed based on scientific need, success
> (or failure) of previous experiments, weather forecast conditions,
> platform/instrument statue, and remaining resources. The meetings will
> be held between 15001800 (non‑flight day) and around 1700 (30 minutes
> after aircraft land on flight days). See section 7.3 for the daily
> schedules.
>
> The following persons or their designated alternate are expected to
> attend:
>
> i\. Participating FST Members;
>
> ii\. Mission Meteorologist;
>
> iii\. Aircraft Coordinators;
>
> iv\. Field Site Coordinators;
>
> v\. Experiment Representatives;
>
> vi\. Operations Manager;
>
> vii\. Other project support personnel.
>
> 5.7.2 Weather Briefing
>
> A weather briefing will be scheduled for each day during the Mission
> Selection Team meeting. A single morning briefing will be held on each
> flight day. The briefings will be presented
>
> 5.7.3 Preflight Status Briefing
>
> A meeting will be held at least two (2) hours before each flight
> experiment to review the latest weather information, review the flight
> plans, instrument statue, and make a go/no‑go decision. This meeting
> will not be used to attempt major alteration to the prime flight plan.
> If the prime flight plan cannot be used and the alternate is not
> suitable, then the mission will be cancelled. The following should be
> in attendance:

i\. Mission Meteorologist;

ii\. Aircraft Coordinators;

iii\. Operations Manager;

iv\. Mission Scientist and/or Associate Mission Scientist.

5.7.4 Mission Debriefing

> After each flight a debriefing will be held to review all aspects of
> the mission from weather conditions to instrument performance. The
> following persons are expected to attend:
>
> i\. Operations Manager;
>
> ii\. Aircraft Coordinators;
>
> iii\. Field Site Coordinators;
>
> iv\. Mission Scientist;
>
> v\. Alternate Mission Scientist;
>
> vi\. Experiment Representatives.
>
> 5.7.5 Data Intercomparison Meetings
>
> During the field mission, experimenters are encouraged to informally
> discuss their results with each other and exchange ideas. Meetings may
> be called intermittently for the intercomparison of data, to ensure
> the proper dissemination of supporting information among the
> participants, and to encourage current and future collaboration.

5.7.6 [Nominal Schedule for Non-Flight Day]{.underline}

> Table 18 lists the schedule for days during which there is no aircraft
> flights scheduled
>
> Table 18 - Schedule for non-flight days
>
> **Event Time Local Time Event**
>
> 1500 - 1700 Planning Session
>
> Weather briefing
>
> Develop prime and backup mission plans
>
> 1700 Inform surface sites, NWS

5.7.7 [Nominal Schedule for Flight Day]{.underline}

> Table 19 lists the schedule of events for experiment flight days.

5.8 Work Schedules

The number of hours per day and days per week worked by members of
various instrumentation teams is the responsibility of the Pls. The work
schedules of government technicians, government contract personnel, and
pilots are subject to specific regulations. The number of aircraft crew
members authorized to operate aircraft systems will limit access to the
aircraft to a maximum of 16 hours per day. We intend to operate 7 days
per week throughout the Cirrus IFO-11 Mission with an average work day
of 8-10 hours.

5.9 Aircraft Access

On non-flight and flight days the aircraft will normally be open and
power available at 0700, or at least 3 hours before take-off, and will
be secured at 1800. Access to aircraft outside of these times must be
coordinated through the Aircraft Coordinator and requests should be made
at least 4 hours in advance.

Only designated aircraft crew members will open the aircraft, apply
power, and operate the power distribution panel controls. Experimental
apparatus under power will not be left unattended. Under no
circumstances will aircraft be left open and unattended.

Table 19 - Schedule for flight days (assume 1430 Local Time Polar
Orbiter overflight).

**Event Time Local Time Event**

T - 3 0800 - 0900 Weather Briefing

Surface site input

Experiment status

1200Z soundings

Go/No Go decision

T - 2 0900-0930 File flight plans

Inform surface sites

Brief flight crews

Go/Delay

T - I 1000 Weather update

Call surface sites, etc. if delay

T-0 1100 Aircraft take off

\- ER-2

1200 - King Air, Citation

1300 - Sabreliner

TL 1630 Aircraft land

Experiment debrief

TL + 1/2 1700 Secure aircraft

TL + 1 1700 - 1800 Planning session

Experiment summary

Weather debrief

Next day experiment planning

Develop prime and backup missions

Call to surface sites, NWS, etc.

> 5.10 Flight Personnel
>
> The number of persons on the aircraft may vary between flights. In
> general the following persons or their alternates will be on the
> aircraft:
>
> [ER ‑]{.underline} 2: Pilot only
>
> [King Air]{.underline}: 2 Pilots
>
> Roelof Bruintjes
>
> Andy Heymsfield
>
> [Sabreliner:]{.underline} 2 Pilots
>
> Max Trueblood
>
> Graeme Stephens,
>
> Andy Heymsfield, or
>
> Graduate Research Assistant
>
> [Citation]{.underline}: Pilot
>
> Co‑Pilot
>
> Michael Poellot
>
> Technician
>
> 5.11 Safety Procedures and Operations Requirements
>
> 5.1 1.1 Aircraft
>
> i\. No smoking while on‑board the aircraft.
>
> ii\. No alcoholic beverages on‑board aircraft.
>
> iii\. Each person must be in his/her assigned seat during each
> take‑off and landing.
>
> iv\. Each person must have flotation gear readily accessible and must
> know how to use it.
>
> v\. The passage way down the aircraft must be clear at all times.
>
> vi\. All carry‑on gear must be secured before take‑offs and landings.
>
> vii\. Only designated aircraft crew members will operate the power
> distribution panel controls.

viii\. In the event of a power outage, all instrumentation power
switches must be set to \"off\" position before power distribution panel
is reset. Experiments will be brought on‑line in sequence, if necessary,
to avoid transient overloads.

> ix\. One person with each experiment must monitor the intercom at all
> times and remain with
>
> his experiment.
>
> x\. The Aircraft Coordinator is the interface between the flight crew
> and the experimenters.
>
> xi\. Technical crew members are not to enter the flight deck without
> permission.
>
> xii\. In the event of an unscheduled landing at an airport other than
> its field base of operations,
>
> the Aircraft Coordinator will be the spokesperson for the technical
> crew members.
>
> However, the aircraft commander is responsible for all persons and the
> aircraft.
>
> xiii\. The aircraft commander is ultimately responsible for the safety
> of each flight and is
>
> expected to take whatever actions are required to ensure that safety
> regardless of flight
>
> plans and experimenters' desires.
>
> 5.11.2 Lidar
>
> An important concern is that lidar operations are conducted in such a
> way as to be eyesafe to \"round and aircraft personnel. (The infrared
> CO2‑lidar is eye‑safe.) This is generally not a problem for vertically
> pointing systems. However, the scanning lidar (VIL) and some of the
> other lidars can be a hazard. Spotters can be used to monitor
> intruding commercial, private, and military air traffic and scan
> patterns can be coordinated with research aircraft activities.
> Operations may have to be suspended during aircraft missions if the
> level of ground‑to‑air communications required to ensure crew safety
> proves burdensome to the pilots or if situations become too complex to
> insure safe operations. A plan to adequately deal with *eye‑safety*
> issues will be formulated by each of the lidar principal investigators
> and submitted to the appropriate government agencies, such as the FAA
> offices in Kansas City and Oklahoma City.

5\. l 2 Flight Constraints

> Section 4.3.3.2 describes the detailed flight plans for each of the
> experiment objectives. The flight plans will depend upon specific
> meteorological conditions and the operational limitations of the
> aircraft. This section will describe some of these aircraft
> limitations.
>
> The advanced technology instrumentation flown on some of the aircraft
> may require from 15 to 30 minutes after take‑off to reach a stable
> operating condition. During this \'warm‑up\' period the aircraft will
> be operated away from the experiment region to avoid possible flight
> through the aircrafts\' engine exhaust over the test area and thereby
> contaminate the scientific measurements. In addition, during
> experiment flights, the aircraft will operate under Visual Flight
> Rules (VFR) conditions and will generally avoid clouds during the
> warm-up phase of each flight.
>
> Therefore, in order to have the flexibility to efficiently conduct the
> Cirrus IFO‑II, the mission will require approval from the FAA and
> military authorities to operate each of the aircraft in a prescribed
> volume of airspace in and about the stases of Kansas and Oklahoma.
>
> All flight operations will be in accordance with existing rules and
> regulations governing
>
> aircraft operations in U.S. airspace. The appropriate aviation
> officials in Kansas City will be
>
> briefed 12 to 24 hours in advance of any experiment flight, and they
> will be provided with a
>
> detailed flight plan including geographic coordinates, altitudes, and
> mission time‑line.
>
> 5.13 Flight Go/No Go
>
> Any one of the following conditions or circumstances will constitute a
> no‑go decision:
>
> i\. One member of the required flight crew is ill and there is no
> adequate replacement;
>
> ii\. Aircraft malfunction;
>
> iii\. Failure of communication system on aircraft (must have two
> working VHF transceivers
>
> and one HF radio);
>
> iv\. Failure of either INS or Omega navigation system if operations
> beyond VORTAC range;
>
> v\. Less than two functioning navigation systems for operations over
> land;
>
> vi\. Unsafe equipment or materials on‑board aircraft;
>
> vii\. Intoxicated technical or aircraft crew member;
>
> viii\. Forecast IFR flight conditions in both primary and secondary
> flight plan areas;
>
> ix\. Forecast IFR conditions at field base plus or minus 2 hours of
> recovery time; and,
>
> x\. Non‑operational statue of critical experiment instrumentation
> system in accordance with
>
> previously established rules governing adequate use of mission
> resources.
>
> 5.14 Mission Abort
>
> The following conditions or circumstances may cause a mission abort:
>
> i\. Illness among critical flight crew members;
>
> ii\. Aircraft mechanical or electrical malfunction;
>
> iii\. Communications or navigation equipment malfunction;
>
> iv\. Development of adverse weather,
>
> v\. Injury to crew member;
>
> vi\. Unruly conduct by crew member;
>
> vi\. Attempt to alter experimental equipment power cables;
>
> viii\. Changes or attempted changes to any aircraft system;
>
> ix\. Interference with any aircraft crew member or failure to follow
> instruction of aircraft
>
> crew members.
>
> x\. Non‑operational statue of critical experiment instrumentation
> system in accordance with
>
> previously established rules governing adequate use of mission
> resources.
>
> 5.15 Medical Considerations
>
> 5.15.1 General
>
> Persons with potentially serious medical problems should inform the
> Operations Manager and work out contingency plans for medical
> attention if the need should arise. As a precaution all participants
> are urged to bring with them the following:
>
> i\. Up to date medical history;
>
> ii\. List of all medications being used;
>
> iii\. List of all allergies;
>
> iv\. Blood type and analysis if available.
>
> Each person now on medication should bring a supply sufficient for the
> mission duration. Those persons who wear glasses should bring an extra
> pair.
>
> 5.15.2 Flight
>
> Persons with respiratory infections or stomach upset are requested not
> to fly. Flight plans will not be altered because of motion sickness.
> Persons susceptible to motion sickness should consuls their physicians
> for medication.
>
> If any potential technical crew member has any concerns about his
> general health, he should consuls his persona! physician and seek
> advice on possible adverse effects of flight stress. No trained
> medical personnel will be on board during these tests.
>
> 5.16 Insurance Considerations
>
> Please note that insurance for the equipment and personnel before,
> during, and after the Cirrus IFO‑II is the responsibility of each
> principal investigator.
>
> 5.17 Public Relations
>
> FIRE operations may generate some degree of interest with the local
> news media. The MST Chairman and Project Manager will be the official
> spokesmen for purpose, plans, and objectives of this mission.
> Information on an individual experiment is the PIs responsibility. Any
> written material with reference to this mission must be coordinated
> with the MST Chairman and Project Manager before release to local news
> media.
>
> 5.18 Aircraft and Site Tours
>
> An Open House will be scheduled at the Operations Center, Coffeyville
> Airport, on the day before the Cirrus IFO‑II begins, on November 12,
> 1991. The meeting will be open to the public, including local news
> media. Representatives of the aircraft and surface instrumentation at
> the Hub site are asked to be present to answer specific questions
> about their instruments, as well as allow for touring of their
> respective equipment.
>
> We may receive additional requests from the local news media,
> government officials, or local scientists to tour the aircraft and see
> the instrumentation during the Cirrus IFO‑II. Such tours should be
> arranged through the Operations Manager who will contact the
> appropriate personnel. PI\'s may be asked to have a knowledgeable
> person on board the aircraft as the spokesman for his experiment.
> Nominally, such individual tours will be scheduled with at least 24
> hours notice and with minimum impact on our mission. These individual
> tours will not be scheduled until 10 days after the open house has
> been held.
>
> 5.19 Operations Phase Out
>
> 5.19.1 Equipment Return
>
> As discussed in section 5.3.2, shipping is a PI responsibility.
> Crating and the filling out of the shipping forms are the
> responsibility of each PI.
>
> 5.19.2 Post‑Mission Calibration
>
> If required, the participating aircraft will be available for a period
> of several days after returning from Kansas for additional \"round
> tests or calibrations on the instrumentation. Please make arrangements
> with the appropriate Aircraft Coordinator.
>
> 5.19.3 Storage of Equipment
>
> All PIs are expected to remove their hardware from the aircraft home
> base hangar within 1 week after aircraft unloading unless prior
> arrangements have been made with the Aircraft Coordinator.
>
> 6.0 DATA MANAGEMENT
>
> Data management is an ongoing activity, beginning immediately in the
> pre‑experiment phase and continuing through the end of FIRE. Most of
> the data management tasks will be performed by the FIRE Investigators
> acting individually or as members of the Cirrus IFO‑II Working Groups.
> The FIRE working group will be the foci for identifying and
> coordinating items relating to the acquisition and use of data as a
> communal resource, working closely with other groups dealing with
> scheduling of platforms, identification of calibration and
> intercomparison needs, collocation requirements, and selection of case
> studies and integrated analyses.
>
> Data management activities in FIRE will insure the exchange of data
> among FIRE investigators that is required to produce the integrated
> analyses of multi‑platform, multi‑scale and mufti‑spectral data sets;
> these integrated analyses are central to the accomplishment of the
> FIRE science objectives. In addition the data management activities
> will insure the availability of FIRE data and analysis products to the
> entire science community. These activities will be carried out by five
> organizational components within FIRE:
>
> \(l\) the individual FIRE investigators,
>
> \(2\) the FIRE Working Groups,
>
> \(3\) the FIRE Data Management Working Group,
>
> \(4\) the FIRE Central Archive, and
>
> \(5\) the FIRE Project Office.
>
> The strategy embodied in this organization is to disperse most of the
> data [reduction and processing]{.underline} functions to the FIRE
> investigators engaged in collecting and analyzing the data, but to
> hold the resultant data sets and analysis products centrally for ready
> access by all FIRE investigators. The FIRE Central Archive (FCA) and
> the FIRE Project Office will provide a [centralized]{.underline}
> source of information and copies of data which are centrally archived,
> whereas the FIRE Working Groups, composed of the investigators, will
> coordinate the [decentralized]{.underline} data reduction and analysis
> activities. In addition, the FIRE Central Archive will transfer, from
> time to time, certified FIRE data to the NASA Climate Data System
> (NCDS) for permanent archive and for open access by the scientific
> community.
>
> 6.1 Data Products
>
> There are several types of data products that will be acquired,
> submitted, and archived at the FIRE Central Archive. These products,
> which will be obtained from a variety of instruments onboard
> satellite, airborne, or surface‑based platforms during the intensive
> field experiments, are as follows:
>
> i\. Raw data - original observations acquired by the instrument, in
> instrument units
>
> (voltages, etc.).
>
> ii\. Reduced data - observations converted to the physical quantity
> directly sensed by
>
> the instrument with quality control inspection and removal of bad
> data.
>
> iii\. Calibration, quality, and navigation information \--describes
> the conversion to
>
> physical units, the conditions of observation and the location of the
> observation.
>
> iv\. Instrument documentation and data tape format description.
>
> v\. Value‑added products \--physical quantifies derived from the
> observations,
>
> including documentation on the analysis algorithm and any auxiliary
> data sets
>
> used in the analysis.
>
> vi\. Data for special case studies which have been arranged for
> intercomparison of
>
> multi‑platform observations.
>
> vii\. Data selected for special processing to facilitate model
> studies.

viii\. Catalog \--information about the data holdings of the individual
PIs, including location of the data holdings instrument(s) performing
the observations; resolution and area coverage of the data; date, time,
and location of the observations; format of the data; and analysis
statue of these data.

> ix\. Status and bibliography of FIRE publications.
>
> Appendix A gives a description of the platforms, instruments, and data
> products for each
>
> instrument participating in the FIRE Cirrus IFO‑II. Data products are
> described for raw data
>
> (investigator archived), reduced data (for the FIRE Central Archive),
> and value‑added data
>
> (FIRE Central Archive).
>
> 6.2 Data Management Responsibilities
>
> 6.2.1 Principal Investigators
>
> All data reduction and analysis functions in FIRE reside with the
> scientists carrying out their research as part of FIRE. To encourage
> the interactions of these researchers needed to integrate the various
> observations and models into a more comprehensive understanding of
> clouds, FIRE investigators will have free access to all data sets
> collected during FIRE, either by individual principal investigators or
> collected from satellites. Coordination of data analysis and modeling
> activities requires all FIRE principal investigators to perform
> certain other tasks as part of the FIRE data management. These
> functions are described in the FIRE Phase II: Cirrus Implementation
> Plan, 1990.
>
> 6.2.2 Cirrus Working Group
>
> The data management responsibilities of the individual principal
> investigators, as dispersed elements of the FIRE data processing
> system, could become onerous if not coordinated properly. Therefore,
> the Cirrus Working Group must govern these individual activities to
> insure progress toward the FIRE science objectives. The data
> management functions of the Cirrus Working Group are described in the
> FIRE Phase II: Cirrus Implementation Plan, 1990.
>
> 6.2.3 FIRE Data Management Working Group
>
> The Data Management Working Group (DMWG) will be comprised of key
> members from the Cirrus and ASTEX working groups, as well as from the
> FIRE Central Archive. The FIRE Data Manager will chair the DMWG. The
> responsibilities of the DMWG are described in the FIRE Phase n: Cirrus
> Implementation Plan, 1990.
>
> 6.2.4 FIRE Central Archive
>
> NCDS at Goddard Space Flight Center will serve as the FIRE Central
> Archive. NCDS is an interactive, easy‑to‑use, on‑line, generalized
> scientific information system. It provides uniform data catalogs,
> inventories, and access methods, as well as manipulation and display
> tools for a large assortment of Earth, ocean, and atmospheric data for
> the climate‑related research community. Programs conducted by NASA
> sponsored investigators, such as climate, weather, severe storm
> research, cloud and land‑surface climatology, can be supported by the
> system.
>
> The FIRE Central Archive will provide a centralized data holding and
> data cataloging service in order to facilitate easy access to all FIRE
> data by all FIRE investigators. Since most of the satellite data are
> not collected directly by FIRE principal investigators, the Central
> Archive
>
> will also be responsible for holding of the satellite data sets
> required for FIRE research from the relevant satellite operating
> agencies. The specific data management functions of the Central
> Archive are described in the FIRE Phase II: Cirrus Implementation Plan
> 1990.
>
> 6.2.5 FIRE Project Office
>
> FIRE data management structure vests the primary data processing
> function with the individual scientific investigators, the information
> and archival functions with the Central Archive, and the
> decision‑making with the FIRE Working Groups. The Project Office must
> provide for liaison among these different groups. The specific data
> management functions of the project office are described in the FIRE
> Phase II: Cirrus Implementation Plan 1990.
>
> 6.3 Standard Data Format
>
> The data acquired by the individual experimenters will be reduced to
> final values and forwarded to the appropriate working group and FIRE
> Central Archive. The format for the submittal of data to the archive
> will be in a mutually agreed upon format, such as the FIRE Standard
> Data Format given in appendix D or NCDS\'s common data format (CDF).
> This format is a flexible, self‑contained data encoding format that
> allows for access to the data without previous knowledge of the
> contents or format. In addition, it allows for a written description
> of pertinent remarks to be included in the data file.
>
> Transfer of the final data between the investigators and the FIRE
> Central Archive may be accomplished by electronic transfer or by
> mailing of appropriate media.
>
> 6.4 Data Schedule
>
> 6.4.1 Post‑Mission Debrief
>
> After each flight mission there will be a post‑mission debriefing of
> all the experimenters. This debriefing is intended to communicate and
> document pertinent subjective observations made during the completed
> mission and allow the experimenters an opportunity to modify
> subsequent plans or procedures for the following experiment. Each
> experimenter should have a \"quicklook\" capability for inspection of
> their sensor performance. A copy of the \"quicklook\" data (raw strip
> charts, tables, etc.) may be submitted to the Data Manager for
> possible comparison/correlation with other experiment data.
>
> 6.4.2 Post‑Experiment Debrief
>
> A post‑experiment debriefing will be held at the conclusion of the
> field experiment. Each experimenter will describe their sensor
> performance, a summary of sensor operating times, a sample of data
> obtained, and a description of the data format that is planned to be
> submitted to the data archive. The Cirrus Working Group will review
> the missions and measurements obtained during the mission. If
> appropriate, it will prioritize key areas of data reduction and
> analysis (such as case study days), identify possible data
> collaboration and exchange, and modify the data reporting schedule.
>
> 6.4.3 Preliminary Data Analysis Workshop
>
> A preliminary data analysis workshop will be held approximately three
> months after the conclusion of the mission. The experimenters will
> describe the performance of their sensors, a sample of the preliminary
> [reduced]{.underline} data, an estimate of the sensor accuracy and
> precision, and report on key measurement results. At the time of the
> Data Analysis Workshop, the preliminary [catalog]{.underline}
> information will be submitted to NCDS. The Cirrus Working Group will
> review the measurements and analyses obtained to date, identify those
> areas requiring additional investigations, and determine the specific
> details of each investigation that is to be pursued.
>
> 6.4.4 Final Reduced Data Submittal
>
> Approximately 9 months after Cirrus IFO‑II, the experimenters will
> submit the final [reduced]{.underline} data products to NCDS (with a
> hard copy to the Data Manager). The data products should be in FIRE
> Standard Format, as described in appendix D. At the same time, updated
> catalog information should also be submitted.
>
> 6.4.5 FIRE Access to Data Archive
>
> Within one month after the [reduced]{.underline} data products have
> been received by NCDS, the data will be available to the FIRE
> experimenters through electronic access. NCDS capabilities, such as
> data subset and plotting, may be used.
>
> 6.4.6 Review of Results/Science Planning Workshop
>
> Approximately one year after the IFO, a Science Workshop will be held
> to review the key research results. The Cirrus Working Group will
> review each of the major scientific objectives (as described in
> Section 2.0) in light of the measurements and analyses obtained to
> date. The Cirrus Working Group will integrate the individual
> measurements into several comprehensive case study data sets and where
> appropriate will compare the measurements with preliminary
>
> theory or model predictions. Some of the individual investigations may
> possibly be integrated in. a broader cloud‑radiation context.
>
> 6.4.7 Open Access to Data Archive
>
> After the certification of the data has been completed, the data
> archive will be transferred to NCDS for release to the scientific
> community. Any proprietary rights (see section 6.5) to the data and
> data interpretation will be voided at this time.
>
> 6.5 Data Protocol and Publications Plan
>
> This data protocol and publication plan has been prepared to encourage
> an orderly and timely analysis, interpretation, and publication of the
> data obtained during the second phase of FIRE. It is hoped that the
> development and distribution of this plan will enhance the atmospheric
> science output by promoting cooperation among the investigators and
> encouraging the early publication of results, thereby enriching the
> scientific interpretation of the data obtained from single and
> ensemble of instruments. The FIRE Working Groups are responsible for
> the certification of data submitted to the permanent FIRE data
> archive, the NCDS. Once the certification process is completed, all
> data residing in the FIRE data archive at NCDS will be released to the
> scientific community. During the certification process period, a set
> of data protocol and publication \"round rules, as described in the
> FIRE Phase II: Cirrus Implementation Plan (1990), will be agreed upon
> and abided to by all FST members as a condition of their participation
> in the FIRE project.
>
> 7.0 SCHEDULES
>
> 7.1 1991 Cirrus IFO‑II Major Milestones

![](media/image30.wmf){width="6.361111111111111in"
height="8.23611111111111in"}

> Figure 13a ‑ Cirrus IFO‑II Major Milestones

![](media/image31.wmf){width="7.286111111111111in"
height="8.627777777777778in"}

> Figure 13b ‑ Cirrus IFO ‑ II Major Milestones‑continued

7.2 Cirrus IFO‑II Operations Schedule

> ![](media/image32.wmf){width="6.944444444444445in"
> height="8.444444444444445in"}
>
> Figure 14 ‑ Cirrus IFO‑lI operations schedule.
>
> 7.3 PERT Chart for Cirrus IFO‑II Project Management
>
> ![](media/image33.wmf){width="7.486111111111111in"
> height="8.958333333333334in"}
>
> 8.0 REFERENCES

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> Wielicki, B.A., A.J. Heymsfield, R.W. Welch, J.T. Suttles, J.D.
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