BOREAS AFM-01 NOAA/ATDD Long-EZ Aircraft Flux Data over the SSA

Summary

This data set contains measurements from the NOAA/ATDD Long-EZ Aircraft 
collected during the 1994 IFCs at the SSA.  These measurements were made from 
various instruments mounted on the aircraft.  The data that were collected 
include: aircraft altitude, wind direction, wind speed, air temperature, 
potential temperature, water mixing ratio, U and V components of wind velocity, 
static pressure, surface radiative temperature, downwelling and upwelling total 
radiation, downwelling and upwelling longwave radiation, net radiation, 
downwelling and upwelling PAR, greenness index, CO2 concentration, O3 
concentration, and CH4 concentration. There are also various columns that 
indicate the standard deviation, skewness, kurtosis, and trend of some of these 
data. The data are stored in tabular ASCII files.
 
Table of Contents

   *  1 Data Set Overview
   *  2 Investigator(s)
   *  3 Theory of Measurements
   *  4 Equipment
   *  5 Data Acquisition Methods
   *  6 Observations
   *  7 Data Description
   *  8 Data Organization
   *  9 Data Manipulations
   *  10 Errors
   *  11 Notes
   *  12 Application of the Data Set
   *  13 Future Modifications and Plans
   *  14 Software
   *  15 Data Access
   *  16 Output Products and Availability
   *  17 References
   *  18 Glossary of Terms
   *  19 List of Acronyms
   *  20 Document Information

1. Data Set Overview

1.1 Data Set Identification

BOREAS AFM-01 NOAA/ATDD Long-EZ Aircraft Flux Data over the SSA

1.2 Data Set Introduction

This data set contains measurements from the National Oceanic and Atmospheric 
Administration (NOAA) Atmospheric Turbulence and Diffusion Division (ATDD) Long-
EZ Aircraft collected during the 1994 Intensive Field Campaigns (IFCs) at the 
BOReal Ecosystem-Atmosphere Study (BOREAS) Southern Study Area (SSA).  These 
measurements were made from various instruments mounted on the aircraft.  The 
data that were collected include: aircraft altitude, wind direction, wind speed, 
air temperature, potential temperature, water mixing ratio, U and V components 
of wind velocity, static pressure, surface radiative temperature, downwelling 
and upwelling total radiation, downwelling and upwelling longwave radiation, net 
radiation, downwelling and upwelling photosynthetically active radiation (PAR), 
greenness index, CO2 concentration, O3 concentration, and CH4 concentration.  
There are also various columns that indicate the standard deviation, skewness, 
kurtosis, and trend of some of these data.  The data are stored in tabular 
American Standard Code for Information Interchange (ASCII) files.

1.3 Objective/Purpose

The primary objective was to measure the vertical flux density of sensible and 
latent heat, CO2, ozone, and momentum for extrapolating surface-based 
measurements to regional scales. An ultimate objective is to develop algorithms 
to relate boundary-layer processes to satellite-derived data.

The AFM-01 team measured water vapor, sensible heat, CO2, and O3 air-surface 
exchange from the boreal forest to study the factors that control spatial 
variability of the exchange.  Scalar flux densities were measured with ATDD's 
Long-EZ flux aircraft.  The purpose of its flights was to observe energy, 
momentum, carbon, and ozone air-surface exchange with a 3-km resolution.  
Additionally, supporting meteorological parameters such as temperature, 
humidity, CO2 and O3 concentration, wind speed and direction, surface 
temperature, and incoming and net radiation were observed.  All data were tagged 
with accurate time, position, and altitude.  It is expected that these data will 
also be used to relate surface exchange to radiometric data available from 
satellites, i.e., validation of satellite data.  Through this research, it is 
hoped that techniques can be developed to more accurately model air/surface 
exchange and to use satellite data for global monitoring of landscape health and 
climate change. 

1.4 Summary of Parameters

The following parameters have been submitted to the BOREAS Information System 
(BORIS) data base: temperature, dewpoint temperature, pressure, incoming and 
outgoing PAR, net radiation, wind velocity, H2O mixing ratio, CO2 mixing ratio, 
ozone mixing ratio, sensible heat flux, latent heat flux, momentum flux, CO2 
flux, O3 flux, aircraft position, altitude (radar and pressure), and surface 
temperature.

Profile parameters are not available at this date.

1.5 Discussion

NOAA operated the Long-EZ in the one 1993 IFC and in all three 1994 IFCs.  
However, only the 1994 data are included in this data set.  The main purpose of 
Long-EZ flights was to observe energy, momentum, ozone, and carbon dioxide air-
surface exchange.  The Long-EZ's strength is its ability to observe spatial 
variability in surface exchange with a 3-km resolution.  This is accomplished by 
flying low (at 10 to 15 m above the surface) and slow (50 m/s) while making high 
frequency eddy flux measurements.  Due to the short sampling time of 60 s, the 
flux variance in the reported 3-km segments is large.  However, each 3-km 
segment is an unbiased estimate of the mean, and variance can be reduced by 
transects' superposition.  Ideally, six repeated transects should be 
superimposed.  This is usually possible since a key element of the Long-EZ 
flight plans is repeated observations.

The data were collected during straight and level flux runs over the BOREAS site 
and in various project areas.  A variety of flight strategies is reported (the 
Candle Lake transect, asterisks, grids, "L" patterns, soundings, etc.), from 
those described in the BOREAS experimental plan.  The archive data include 
segment-averaged data, focusing on the fluxes, and the supporting 
meteorological, radiometric and aircraft positional data.  No attempt will be 
made to archive the high rate (40 Hz) "raw" or processed output data (POD), 
which can be acquired from ATDD by special request.  The references give a 
complete description of the Long-EZ and its instrument systems.  The following 
table gives a quick overview of flight operations.

BOREAS 1993-1994
NOAA Long-EZ Flight Operations Summary

ITEM              IFC 93    IFC 1    IFC 2    IFC 3    TOTAL
----              -----     -----    -----    -----    -----
Flight Hours        46        83       75       68      272
OJP Passes          84        98       33       71      296
OA Passes           --        44       47       23      114
OBS Passes          --        37       --       32       69
Candle Lake         15        35       55       32      137
Grid Pattern        --        --        5        3        8
"L" Pattern         --         6       14       --       20
Calibrations        --        28        5        2       35
Intercomparisons    --        18        8        2       28

NOTES:  1. Summary excludes experimental sampling patterns and miscellaneous 
sites.  2. Flight hours include all flight operations except ferry to and from 
Tennessee.  3. A pass is any flux tower crossing.  Site-specific patterns such 
as "asterisk", 8's, and button holes were centered on the flux towers.

1.6 Related Data Sets

BOREAS AFM-02 King Air 1994 Aircraft Flux and Moving Window Data
BOREAS AFM-02 Aircraft Sounding Data
BOREAS AFM-03 Aircraft Flux and Moving Window Data
BOREAS AFM-03 Aircraft Sounding Data
BOREAS AFM-04 Aircraft Flux Data
BOREAS AFM-04 Aircraft Sounding Data

2. Investigator(s)

2.1 Investigator(s) Name and Title

Timothy L. Crawford and Dennis Baldocchi
Atmospheric Turbulence and Diffusion Laboratory
NOAA
Oak Ridge, TN 
(865) 576-0452
(865) 576-1327 (fax)
T29@ornl.gov

2.2 Title of Investigation

AFM-01: Experimental and Modeling Studies of Water Vapor, Heat and CO2 Exchange 
over a BOREAL Forest

2.3 Contact Information

Contact 1
------------
Laureen Gunter/Ed Dumas
Atmospheric Turbulence and Diffusion Laboratory
NOAA
Oak Ridge, TN
(865) 576-1246
(865) 576-3500
(865) 576-1327  (fax)

Contact 2
------------
David Knapp
NASA/GSFC
Greenbelt, MD 
(301) 286-1424
(301) 286-0239 (fax)
David.Knapp@gsfc.nasa.gov

3. Theory of Measurements

Air-surface exchange, or the surface flux, is a fundamental boundary condition 
controlling the atmospheric mass, momentum, and energy budgets.  The species 
exchanged at the surface passes through the near surface boundary layer by 
turbulent transport.  Thus, the surface exchange may be determined by measuring 
the near-surface turbulent or "eddy" flux.  The eddy flux measurement is simple 
in concept, mathematically expressed as the covariance

F = <(rw)'s'>                             3.1

Here (rw)' is the turbulent fluctuation of the product of the dry air density 
and vertical velocity (i.e., dry air mass flux density), and s' is the turbulent 
fluctuation in the mixing ratio, relative to dry air, of the species of 
interest.  The angle brackets indicate the appropriate ensemble average.

This method has a first-principles basis, and a direct noninvasive nature. Since 
the near-surface flux is directly observed, the only assumption is that the flux 
divergence or gradient between the measurement and the surface is small.  This 
assumption is valid when the mean transport, sources, and storage terms within 
the conservation equation are small.  The reliability of this assumption weakens 
with increasing measurement altitude, and/or increasingly complex atmospheric 
and site conditions.

The measurement principles for wind velocity and species concentration are well 
developed.  Since the flux measurement is made above the surface without 
disturbing the surface, it cannot influence the exchange observed.  Tower 
observations using a 15-min time scale, and airborne observations using a 3-km 
space scale, give data with sufficiently small time/space scale to permit the 
process studies needed to improve predictive capabilities.  In the last 10 
years, the accuracy of this technique has improved because of significant 
advancements in instrumentation and processing techniques.

However, the details associated with proper instrument operation, data 
processing, and data interpretations are complex.  This is especially true for 
airborne flux systems.  For aircraft, both the instrument systems and data 
processing programs are more complex when compared to tower systems.  For 
example, to determine wind velocity on an aircraft, the air velocity relative to 
the sensors is added to the sensor velocity relative to Earth.  Both vectors are 
large and nearly cancel each other out (i.e., similar magnitude, opposite 
signs).  Neither vector can be directly observed, but must be synthesized from 
many sensors.  The synthesis process is intolerant to phase or amplitude errors 
introduced by sensors, data systems, or processing algorithms.

Eddy Flux Measurement Theory

The eddy flux method allows the short-term measurement of flux densities 
(vertical transport of mass, momentum, and energy per unit area and time).  The 
measurement becomes especially powerful, but often difficult to interpret, when 
made from an aircraft.  Aircraft turbulence data derive their power from 
information density per unit time, and the spatial freedom of the measurement 
platform.  Both require greater effort in an analysis.  Further, interpretation 
of aircraft data becomes more difficult whenever the data set also contains 
spatial trends and inhomogeneities.  Mass conservation provides the basic 
framework for correct interpretation.  Conservation of a conservative species, 
s, requires that the time rate of change of s within a control volume be 
balanced by the mean and turbulent flux through the volume's boundaries.

From the Long-EZ, fluxes are measured usually around 15 m above the surface 
(higher from other aircraft and lower from towers).  The flux measurement 
accurately defines the flux occurring at the flight altitude and along the 
flight track.  However, most are interested in the surface flux.  The flux 
observed at a flight altitude represents the surface flux if the following 
conditions are met.

1) The flight altitude is low enough to be within the constant flux layer.  
Above this, flux divergence becomes increasingly important with increasing 
altitudes, which makes the observed flux no longer representative of the surface 
flux.  Such flux divergence usually causes an underestimate of the surface flux, 
but not always.  Typically, mitigating concerns about flux divergence requires 
measurement within the lowest 10% of the turbulent boundary layer.  With the 
exception of stable night boundary layers, the Long-EZ's 15 m sampling altitude 
satisfies this condition.  However, the importance of storage and transport 
terms below the flight altitude should be considered.  In unusual situations 
such as front passages, strong temperature, or species advection, such terms can 
still become significant.

2) The underlying surface is homogeneous.  It should extend upwind of the flight 
track for about 100 times the sampling altitude.  Also, it should extend along 
the flight track for a distance equivalent to the space average being applied in 
data processing.  This ensures the development of an equilibrium surface 
boundary layer and adequate sampling time before conditions change.  Airplane 
measurements remain valid whether or not these conditions are met.  However, 
small-scale inhomogeneity greatly increases the difficulty of specifying and 
interpreting the mean state from which the turbulence departs and introduces 
samples from multiple populations into the measurement set.  This difficulty 
increases as the contrast between inhomogeneous regions increases.

3) Stationary meteorological conditions should prevail during sampling.  Such 
conditions as frontal passage and nightfall clearly violate this, featuring 
important contributions from the horizontal transport or storage terms, 
explicitly rejected by Eq. 3.1.  However, less abrupt change can also be 
important. For example, if the air is warming 3 deg/hr, the heat flux at 15 m 
(Long-EZ flight level) will be 20 W/m2 less than at the surface due to storage.

4) Below the measurement height, s must be a conservative property.  Fast 
chemical reactions involving s invalidate this assumption.  For example, ozone 
reacts rapidly with NO.  If there is a significant NO emission below the 
sampling altitude (soil flux or automobile emissions), it could easily lead to 
an incorrect interpretation of the observed flux.

Eddy Flux Technique

A significant part of the complexity of this measurement lies in separating 
turbulent fluctuation from mean, and defining an appropriate ensemble average.  
Equation 3.1 is not computationally useful until the turbulent fluctuations are 
defined.  Traditionally, the fluctuations are defined as

s = s' + S                                3.2

where S is the appropriate ensemble mean of s.  Given this definition, Eq. 3.1 
may be rewritten as

F = <[(rw) - (RW)](s -S)> = <(rw)s-(RW)S>           3.3

Here (RW) is not the product of the mean of the dry air density and the mean 
vertical velocity but the mean of their product.  For heat flux, s =Cp*T where 
Cp is the moist air specific heat at constant pressure. Cp depends locally 
(i.e., at 40 Hz) on water vapor concentration.  T is the potential temperature.  
The use of potential temperature compensates for the compressible nature of the 
atmosphere.  Since there is a correlation between w and the aircraft altitude, 
the use of potential temperature is necessary to eliminate this false (rw)t 
correlation.  For latent heat flux, s = Lq where L is the local temperature-
dependent evaporation energy for water and q is the water vapor mixing ratio 
relative to dry air.  For CO2, s becomes the CO2 mixing ratio relative to the dry 
air component.  This approach satisfies the constraint outlined by Webb et.al. 
(1980) (no flux of dry air), and implicitly corrects all fluxes for heat and 
water vapor transport.

On a tower, the mean is a time average.  The fluctuation is then obtained as s' 
= s - S where S is the average over periods of around 15 to 30 min.  However, s 
observed from an airplane contains both space- and time-related trends.  In 
aircraft flux data, a space trend should also be considered.  This is a tedious 
and difficult correction that requires much investigator interpretation.  Only 
time trends have been removed for data submitted to BORIS.

Eddies in a wide range of scales contribute to turbulent transfer.  Successful 
eddy flux measurement requires proper sampling over this spectrum.  The eddy 
size is expressed by a dimensionless frequency, nz/u, where n is the eddy size 
as a frequency, z the sampling height, and u the eddy transport speed past the 
sensor.  The important eddy size ranges contributing to turbulent transfer are 
typically within 0.005 < nz/u < 5.  For the Long-EZ, u = 50 m/s and z = 10 m.  
Therefore, from the Long-EZ, eddy sizes between 1.25 m and 1,250 m are 
important.  Over deciduous forest during typical daytime turbulent conditions, 
little flux contribution occurs outside this range (Anderson et al. (1986)).  
However, due to the greater roughness of the BOREAS site, we suspect the 
important eddy flux range may be driven to longer wavelengths.  The nz/u scaling 
points out the need for and advantage of fast-response turbulent measuring 
systems.  Fast-response sensors/data systems combined with low-altitude flying 
allow the contributing eddies to be sampled in a shorter time and enhance the 
spatial resolution of the flux observation.

The significant heterogeneity of the BOREAS experimental site makes it difficult 
quantitatively to specify the important eddy-size range contributing to 
turbulent transfer.  Traditional spectral analysis is not appropriate due to 
strong site heterogeneity.  To address this issue, two Candle Lake transects 
were processed with various covariance time scales or wavelength.  The average 
flux along the transect normalized by the largest covariance result is presented 
in the following table.  As the table shows, little flux is lost even at 20 s; 
therefore, our 60 s choice for BORIS submission is conservative.

Normalized Covariance (%) vs. Wavelength(s)

Wavelength          U*       H       LE        FluxCO2

  5 s  (250 m)     0.05      0.7     0.7        0.8 
 10 s  (500 m)     0.69      0.9     0.8        0.9
 20 s (1000 m)     0.39      0.9     0.9        0.9
 30 s (1500 m)     0.24      0.9     0.9        0.9
 40 s (2000 m)     0.16      0.9     0.9        0.9
 60 s (3000 m)     0.10      0.9     0.9        0.9
 80 s (4000 m)     0.01      1.0     0.9        0.9
100 s (5000 m)     0.03      0.9     1.0        1.0
110 s (5500 m)     0.00      0.9     0.9        0.9

Evaluating the accuracy of the eddy correlation method is not straightforward.  
Factors contributing to uncertainties are instrument errors, sensor time 
response, signal-to-noise ratio, sensor separation distance, height of the 
measurement, signal attenuation due to path averaging, and corruption through 
tubing. Natural variability, due to nonsteady conditions, turbulence 
intermittency, and surface inhomogeneities, can add additional uncertainty.  
Under ideal meteorological and site conditions, natural variability is around 
10%.  Therefore, systems should be designed with an error less than this.  
However, the biggest problems with aircraft data are not related to data 
accuracy, but to data interpretations.  Aircraft data implicitly represent a 
space average.  The spatial variance is usually larger than 10%.

4. Equipment


4.1 Sensor/Instrument Description

The equipment used for the airborne flux measurement includes ATDD's Long-EZ 
flux research aircraft, the airborne flux instrumentation, and ATDD's data 
reduction hardware with software.  These three systems were specifically 
designed and manufactured by ATDD staff to ensure high-fidelity flux 
observations.  The optimum use of this airborne system is boundary layer flux 
measurement.

Long-EZ Description

The Long-EZ flux research aircraft, N3R, is well suited and is specifically 
instrumented for high-fidelity, air-surface-exchange research (Crawford et al., 
1996).  The wide-body Long-EZ is an experimental aircraft built by Timothy L. 
Crawford.  It is a larger, higher-powered and more capable version of the Rutan 
Long-EZ, a two-passenger, high-performance canard airplane.  The aerodynamic 
characteristics of the Long-EZ are well suited for high-fidelity turbulent flux 
measurement.  The pusher configuration leaves the front of the airframe free of 
propeller-induced disturbance, engine vibration, and exhaust.  The small, 
laminar-flow airframe has an equivalent flat plate drag area of 0.2 m2.  As a 
result, the nose region has small flow disturbance and is ideal for high-
fidelity measurements of winds, temperature, and trace species.  The canard 
design cannot stall and has superior pitch stability in turbulent conditions.  
This, combined with its low wing loading, allows for safe low-speed (50 m/s), 
low-altitude (10 m) flux measurement.  For enhanced safety, the Long-EZ is 
equipped with a ballistically deployed safety parachute (deployment requires 0.9 
s).

The Long-EZ has an empty weight of 430 kg and a maximum gross takeoff weight of 
800 kg.  The aircraft service ceiling of 9,000 m must be reduced to 5,500 m 
because of oxygen system limitations. Endurance significantly exceeds 10 hours 
and a 2,000-nm range; however, pilot fatigue precludes routine 10-hour missions.  
More typical operations are two 4-hr or three 3-hr missions.  Although small 
size (low flow distortion) is important to high-quality turbulence measurements, 
it is also a disadvantage.  The small size combined with the current 
instrumentation leaves little room for additional instruments.

Airborne Flux Instrumentation Description

Wind velocity and virtual temperature fluctuations were measured with ATDD's 
turbulence probe (Crawford et al., 1992).  The probe is mounted five chord 
lengths ahead of the wings, where flow disturbance is small.  It carries 
pressure, temperature, and acceleration sensors in a nine-hole pressure-sphere 
gust probe of ATDD design.  This sensor suite is specifically designed to extend 
eddy flux measurement at the higher frequencies required for low altitude 
flight.  A thermistor in the central pressure port provides simultaneous 
temperature measurement, at a location symmetrical with respect to the flow, for 
accurate determination of true air speed and heat flux.  CO2 and water vapor 
fluctuations were measured with an open-path, infrared gas absorption (IRGA) 
analyzer, developed at ATDD (Auble and Meyers, 1992).  This sensor responds to 
frequencies up to 40 Hz and has low noise and high sensitivity (for CO2, 20 
mg/m3/v).  The sensor is rugged and experiences little drift.  A unique 
difference in the Long-EZ instrument system is its pioneering use of a 
differential Global Positioning System (GPS) for extremely accurate position, 
velocity, and platform attitude measurement.

The airborne flux instrumentation and the data system with its associated 
software were specifically designed and built by ATDD (Crawford et al., 1991).  
This system connects to the pilot's digital interface, which controls instrument 
power distribution, two-way "smart" instrument communication, and the data-
storage algorithm.  The data stream is dominated by the high-frequency analog 
signals.  Analog signals are first electronically conditioned by 30-Hz lowpass 
Butterworth anti-aliasing filters.  The conditioned and voltage scaled signals 
are then digitized at 200 Hz.  The 200-Hz data are digitally filtered and 
subsampled to 40 Hz.  Although several other data frequencies are being written 
to disk, all are synchronized to a single clock frequency.  Spectra and co-
spectra data analysis show that the 40-Hz flux data rate is adequate for 
measuring fluxes above forest canopies at the Long-EZ flight speed and altitude.

Data Reduction Hardware With Software 

The eddy flux densities are determined by calculating the covariance between 
vertical velocity and scalar fluctuations while correcting for aircraft speed 
variations (Crawford et al., 1993a).

4.1.1 Collection Environment

Data were collected during IFCs 1, 2, and 3 under flight conditions outlined in 
the BOREAS Flight Plans for flux aircraft.

4.1.2 Source/Platform

The platform used to collect this data was a Long-EZ aircraft built by Timothy 
Crawford.

4.1.3 Source/Platform Mission Objectives

The mission objective was to collect CO2, O3, CH4 concentrations as well as other 
atmospheric and radiation parameters over various BOREAS sites.

4.1.4 Key Variables

The data that were collected include: aircraft altitude, wind direction, wind 
speed, air temperature, potential temperature, water mixing ratio, U and V 
components of wind velocity, static pressure, surface radiative temperature, 
downwelling and upwelling total radiation, downwelling and upwelling longwave 
radiation, net radiation, downwelling and upwelling PAR, greenness index, CO2 
concentration, O3 concentration, and CH4 concentration.  There are also various 
columns that indicate the standard deviation, skewness, kurtosis, and trend of 
some of these data.

4.1.5 Principles of Operation

None given.

4.1.6 Sensor/Instrument Measurement Geometry

ATDD's turbulence and heat flux probe is mounted on the airplane at the end of a 
1-m nose boom.  This places the probe five wing chords in front of the canard 
and six wing chords in front of the main wing.  All high-frequency motion 
(acceleration, pressure, and temperature) sensors are within the nine-hole 
pressure sphere.  The center of the sphere is the origin of the computational 
coordinate system.  A backup fast-response temperature sensor and slow-response 
temperature sensor for calibration reference are mounted on the nose of the 
airplane along with ATDD's fast-response IRGA H2O/CO2 analyzer.  Forward on the 
left side of the nose is the net radiometer.  The small airframe size results in 
very small solid angle interference from the airframe at the nose.  Located at 
the aircraft center of gravity (CG) are the low-frequency reference sensors for 
H2O, CO2, and O3.  The infrared surface temperature sensor, the chilled-mirror 
dewpoint hygrometer, and the fast-response O3 analyzer are also at this 
location.  The infrared temperature sensor is nadir-mounted through the floor.  
With its 15-degree field of view, it "sees" a 5-m-wide footprint.  There are six 
GPS antennae strategically placed around the airframe, which are connected to 
three separate GPS receivers.  The critical system is a four-antennae 
differential GPS (DGPS) attitude system.  Attitude is determined by 
differentially measuring the relative positions, within 1 cm, of nose, tail and 
wing antennae.  The current GPS is limited to operation at 4 Hz. A system 
upgrade with associated software enhancements is expected to allow this system 
to operate at 10 Hz in the future.  When the attitude system output is increased 
to 10 Hz, one of the redundant GPS position receivers and the three-axis gyro 
system at the CG can be eliminated.


4.1.7 Manufacturer of Sensor/Instrument

The microprocessor revolution has accelerated technological advancements in 
instrumentation.  The instrumentation on the Long-EZ has been upgraded 
continuously to keep pace with instrument technology.  Improved instrumentation 
is installed as it becomes available or is found desirable.  Typically, several 
instruments change each year.  The following table lists the instruments, 
manufacturer, location, sampling rate, accuracy, resolution, and units of the 
instruments that were onboard during BOREAS IFCs.

Variable        Name    Manufacture/Model      Loc/Hz  Acc/Res   Unit
-----------------------------------------------------------------------
Acceleration    Ax     Sundstrand/QA-700       P/40    25/10     m/s2
Acceleration    Ay     Sundstrand/QA-700       P/40    50/35     m/s2
Acceleration    Az     Sundstrand/QA-700       P/40    70/50     m/s2
Pressure        Px     SenSym/SCX01            P/40    70/0.6     mb
Pressure        Py     SenSym/SCXL004          P/40    50/0.5     mb
Pressure        Pz     SenSym/SCXL004          P/40    50/0.5     mb
Dif Stc Pres    DelP   SenSym/SCXL004          P/40    50/0.5     mb
Static Pres            Setra/270 (mod)         H/1    0.5/0.01    mb
Attitude        Pitch  TANS VECTOR-Trimble     C/1   0.08/--     deg
Attitude        Roll   TANS VECTOR-Trimble     C/1   0.08/--     deg
Attitude        Head   TANS VECTOR-Trimble     C/1   0.05/--     deg
Position        Lat    DGPS                    P/1     3 / 3     deg
Position        Lng    DGPS                    P/1     3 / 3     deg
Fast temp       Tp     ATDD/u-bead thermistor  P/40   0.1/0.005   C
Mean temperature        RPT/Hy-Cal BA-507-B    P/1    0.05/0.03   C
Dewpoint temp   Td     EG&G/                   C/1    0.5/0.006   C
Water vapor     fast   ATDD/IRGA               H/40   ---/22     g/m3
Water vapor     ref    LI_COR/6262             C/1     1%/0.005  mM/M
CO2             fast   ATDD/IRGA               H/40   ---/0.2    mg/m3
CO2             ref    LI-COR/6262             C/1     <1/0.2    uM/M
O3              fast   ATDD/Chemiluminescence  C/40      /        ppb
O3              ref    Modified TECO            /        /        ppb
-----------------------------------------------------------------------
Notes: Sensor locations:  P - in pressure sphere; H - on probe hatch mountcover; 
C - Aircraft CG

4.2 Calibration

All instruments were calibrated before and after each IFC.  Complex instruments 
(such as CO2 and O3) were calibrated daily.  All instruments undergo a 
comprehensive pre- and post-flight check for correct operation.  The first and 
last data file for each flight go through a quality assurance (QA) procedure 
prior to the next flight.  As part of the QA, takeoff and landing meteorological 
data are checked against conditions observed at the airport.  Additionally, all 
data undergo time-series display, statistical and spectral analysis, and 
preliminary data reduction as part of the QA procedure.

4.2.1 Specifications

Not available.

4.2.1.1 Tolerance

Not available.

4.2.2 Frequency of Calibration

All instruments were calibrated before and after each IFC.  Daily calibrations 
were performed on the CO2 and O3 instruments.

4.2.3 Other Calibration Information

See Section 17 (References).

5. Data Acquisition Methods

Data were collected during IFCs 1, 2, and 3 under flight conditions outlined in 
the BOREAS Flight Plans for flux aircraft.

6. Observations

6.1 Data Notes

None.

6.2 Field Notes

25 May 1994 Flight hours 4.4 (Hobbs) Pilot: TLC
SUMMARY: Today's flight consisted of low-level agriculture runs in the SSA with 
entry in the western corridor, combined with a site specific asterisk pattern 
over Tower 5 (Old Jack Pine).
WEATHER: Mostly clear and sunny.
TAKEOFF: 1744Z, FSS Temp = 7.9 C, Dew Pt = 6.6 C
LANDING: 2045Z 
On ground met readings prior to flight: P = 969.1 mb, T = 25.9 C, Tw = 19.4 C 
NOTE: the on ground pre-flight T and Tw readings are probably wrong, due to a 
problem with the psychrometer.
On ground met reading after the flight: P = 968.0 mb, T = 19.0 C, Tw = 13.7 C.
After flight: 1515 local time, zeroing Li-COR. Li-COR calibration with U.Wyo 
gases: H2O: 0.45; CO2: -1.8, so zero is real close to where it should be.  
Current pot settings are 2.4 (CO2) and 5.0 (H2O).

26 May 19944.4 Flight Hours (Hobbs) Pilot: TLC
SUMMARY: 2 profiles & 5 Candle lake runs at 20 m--very turbulent with strong 
wind. Note: The NCAR Electra flew the Candle Lake line during the same period 
from 100 m to above the boundary layer.
WEATHER: Started clear with 15% Cu building by mid run, some high stratus 
TAKEOFF: 1550Z, FSS Temp 19.3 C; Dew Pt 7.0 Wind; 180/15
LANDING: 2000Z, FSS Temp 22.3 C; Dew Pt 6.1; Alt 29.84
On ground met readings prior to flight: T=20 C, Tw=16.9 C, P=963.4 mb After 
flight met readings: T=22.3 C, Tw=13.3 C, P=961.3 mb 

26 May 1994 Flight hours 1.9 (Hobbs) Pilot: EJD 
SUMMARY: Flight plan was to fly a site specific, asterisk over the Old Aspen 
(OA) site in the SSA.*****NO GYROS FOR THE WHOLE FLIGHT*****
WEATHER: Mostly sunny, some clouds around, windy
TAKEOFF: 2030Z
LANDING: 2220Z
On ground met readings prior to flight: T=22.3 C, Tw=13.3 C, P=961.3 mb 
After flight met readings: T=22.5 C, Tw=12.7 C, P=960.2 mb
Note: When processing data after the flight, it appears the gyros were OFF for 
the entire flight - not malfunctioning. Also, the ozone inlet came off sometime 
during the flight.

27 May 1994 4.3 Flight Hours (Hobbs) Pilot: TLC
SUMMARY: Two site specific runs - asterisks over the Black Spruce Tower, then 
one over the Old Jack Pine tower. CO2 sensor was calibrated prior to flight.
WEATHER: On Takeoff, clear wx conditions - haze to East no clouds directly 
above, thin high stratus. Basically clear all day, with stratus building and 
coming in from the west at about 2000Z - 50%, from morning of about 15%.
Note: BS not a good place for a site specific - there is a lot of heterogeneity: 
lot of little lakes, lot of chopped up stuff - lot ofter rain - looking for the 
best direction that offers a good comparison with the tower. OJP coordinated 
from Piers 53.916N, 104.69W.
TAKEOFF: 1630Z FSS Temp 22 C
LANDING: 2030
On ground met readings prior to takeoff: T=21.6 C, Tw=15.2 C, P=954.7 mb
After flight met readings: T=28 C, Tw=15.4 C, P=952.4

29 May 1994 Flight hours 2.8 (Hobbs) Pilot: TLC
SUMMARY: An OJP site asterisk plan was flown.  In conjunction, the Twin Otter 
was flying an "L" pattern across all tower sites, and the NASA helicopter took 
measurements in the same area.  CO2 IRGA calibration was done prior to flight, 
so there is an updated zero and span available.  Additionally, the probe 
temperature sensor was changed from the glass microbead to the wire microbead; 
therefore, the zero and span of the temperature probe has changed.
WEATHER: Overcast most of the day. At P.A.: cloud est to be 3200 Sct, 9000Bkn, 
25000 Bkn, vis 15 miles. It was cloudier to the southwest when over the site. At 
landing, a system had moved in from the south, and light precipitation had 
begun.
TAKEOFF: 1740Z
LANDING: 2020Z
NOTE: The date and time were set incorrectly, so the first file has the wrong 
time.  The GPS reset the time when the file was closed.  he date had been 27 
May, (edited after the flight).

31 May 1994 Flight hours 5.4 hours (Hobbs) Pilot: TLC
SUMMARY: The flight plan consisted of an intercomparison with the Canadian TO to 
the grid where the TO was to sample.  After that, the Long-EZ flew 7-Candle Lake 
runs.  The NCAR Electra also flew the Candle Lake run.
WEATHER: Clear in the morning, small cumulus by mid-morning, with increasing 
cloud cover by mid-afternoon.  Maximum coverage 25% by the afternoon.
Note: No ozone instruments installed (fast or slow).  Repaired DelP sensor. 
"Hell-hole" access taped up, trying to reduce pressure in cabin to better 
ventilate the temperature probe. 
TAKEOFF: 1615Z FSS Temp = 16.6 C, Dew Pt = 7.1 C, winds 300/5, alt 30.11 
LANDING: 2120Z

1 June 1994 Flight hours 5.1 hours (Hobbs) Pilot: TLC
SUMMARY: Flight plan consisted of asterisks first over BS and OJP, then a Candle 
Lake run with the Twin Otter for intercomparison, followed by an asterisk over 
Old Aspen.
WEATHER: Initially clear (0800L), then clouding over by mid-morning to noon.  By 
landing, the sky was 90% coverage.  Calibration of IRGA recorded to disk prior 
to flight - 3 concentrations: 301.5, 365.8, 415 ppm.  Also, radar altimeter 
failed on the last few files of the prior flight.  And, there are no Magellan or 
ozone instruments.

TAKEOFF: 1445Z FSS Temp=18.2, Dew Pt = 7.6, alt 30.14, winds 120/10
LANDING: 2000Z

1 June 1994 Flight hours 2.6 (Hobbs) Pilot: EJD 
SUMMARY: Flight plan was an asterisk over the Old Aspen site, then a few low 
passes over the Black Spruce site (for the press).  Tape recorder failed, so 
there are no in flight remarks.

2 June 1994 Flight hours 1.1 hours (Hobbs) Pilot: EJD
SUMMARY: Purpose of flight was to do a pitch and wind cal at constant altitude, 
i.e., speed ups/downs, wind box, wind circle.
WEATHER:  Overcast, light precip. 
TAKEOFF: 1450Z
LANDING: 1550Z FSS T = 17, Dew Pt = 8

4 June 1994 Flight hours 2.2 (Hobbs) Pilot: TLC
SUMMARY: This was a calibration, wind box, wind circle, speed pitch up/dn 
flight.  The radar altimeter is back up and working fine.  The ozone instruments 
are still out.
WEATHER: Calm, stable condition.  The winds are very light and out of the NE.  
The haze from the paper plant was in the area, and some crud clouds were in the 
south.  By landing, it was starting to clear out...minor windshift.
TAKEOFF: 1200Z FSS Temp = 9.4, Dew pt = 9.2, alt 29.89, winds calm
LANDING: 1400Z FSS Temp = 15., Dew pt = 12., alt 29.89, winds calm
Notes on landing: looking at paper mill, the winds seem to be 210 deg at the 
surface, then about 230 deg aloft.

4 June 1994 Flight hours 4.5 (Hobbs) Pilot: TLC
SUMMARY: Candle Lake runs coupled with an intercomparison with the Wyoming King 
Air.
WEATHER: Clear, calm, and mostly sunny.  Some cumulus forming.
TAKEOFF: 1500Z FSS T = 16.8, Td = 11.9, winds calm, alt 29.89
LANDING 1930Z FSS T = 22.7, Td = 9.6
Notes: Magellan GPS not working all morning.  The ozone instruments are out.

4 June 1994 Flight hours 2.8 (Hobbs) Pilot: EJD
SUMMARY: Originally there was to be an asterisk to be done over OJP; however, it 
was precipitating over the site, so an asterisk was done over the Black Spruce 
site.
WEATHER: By mid-afternoon, there was about 50% cloud cover, mixed types, mostly 
Cu.
TAKEOFF: 2015Z
LANDING: 2300Z FSS T=24, Td=10
Notes:  Ozone instruments were re-installed for this flight. 

6 June 1994 Flight hours 5.1 (Hobbs) Pilot: TLC
SUMMARY: The "h", "i", "j" L-shaped pattern was flown today.  The KA was going 
to be flying the same pattern, and the Electra was going to be in the same 
vicinity.  In the 2nd portion, different altitudes were flown for flux 
divergence measurements. 
WEATHER: Some cloudiness in the early morning, coupled with ground fog 
progressing to approx. 50% coverage by mid-afternoon. 
TAKEOFF: FSS winds 050/10, alt 29.98, T = 14.1, Td = 11.9
Notes: During the first part of the flight, one of the switches on the gyros 
weren't on...after landing, the switch was turned on, ready for immediate 
takeoff.  At approximately 1100, during flight, the alternator fuse blew, so Tim 
shutoff electrical power and came in.  The fuse was replaced, and there was 
another takeoff at approximately 1215L.  Same problem occurred, and the next 
landing was at approx. 1430L. Additionally, the ozone inlet tube came off 
sometime during flight, so the slow ozone data may be bad.

7 June 1994 Flight hours 4.3 (Hobbs) Pilot: TLC
SUMMARY: Candle Lake runs - the only one of the BOREAS Airforce out there
WEATHER: Windy, warm, blue skies with cirrus to the south. 
TAKEOFF: 1440Z FSS Alt 30.06, winds 090/15
LANDING: 1850Z
Notes: Ozone inlet tube came off sometime during flight yesterday...repaired for 
today's flight.  Before flight, glycol mixed with ethyl alcohol was added to the 
fast-response ozone instrument.  During flight, TLC noted that the fast sensor 
#1 was over sensitive, but that fast sensor #2 seemed OK.  Also prior to flight, 
there was a calibration done on the fast ozone with the new solution, and there 
was a calibration on the CO2instruments with the 3 concentrations.

7 June 1994 Flight hours 3.4 (Hobbs) Pilot: EJD
SUMMARY: Candle Lake runs
WEATHER: Very windy, clear, cirrus to the south.
TAKEOFF: 2000Z Alt 30.02 FSS Winds 090/15G20 T=21.
LANDING: 2330Z FSS T=22.6, TD=-1.0
Note:  The fast ozone sensors ran out of solution sometime during flight.

8 June 1994 Flight hours 4.7 (Hobbs) Pilot: TLC
SUMMARY: Asterisk pattern around Old Jack Pine - first counterclockwise in 15 
deg increments, then counterclockwise in 15 deg increments.
WEATHER: On site, initially clear with cirrus aloft, then gradual increasing 
cloudiness.  Winds along the path were approx 10 m/s.
TAKEOFF: 1530Z FSS T=15.5, Td=6.4, Alt 29.99, winds 120/10
LANDING: 1930Z FSS T=18.7, Td=11.3, winds 230/5
Notes: In-line filter installed on Li-COR 6262 this morning - trying to mitigate 
pollen problems. CO2 and ozone calibration done prior to flight, and in between 
flights.  No TANS pseudo ranges during flight.

8 June 1994 Flight hours 2.5 (Hobbs) Pilot: EJD
SUMMARY: OJP asterisks
WEATHER: Overcast to the south, mostly clear to the north. 
TAKEOFF: 2015Z FSS T = 18.8 C, Td = 11.5 C, winds 190/10, Alt 29.97
LANDING: 2230Z FSS T = 18.4 C, Td = 10.2 C, winds 210/5, Alt 29.97
Notes:  Solution on fast response ozone sensors ran out during flight.

10 June 1994 Flight hours 5.6 (Hobbs) Pilot: TLC
SUMMARY: This flight was an asterisk over the Old Aspen site, and then 5 runs 
along the Candle Lake transect.
WEATHER: Clear in the morning (0800 or so), some ground haze - then by mid-
morning, there was alto-status mixed with cirrus and some small Cu.  By mid-
afternoon the wind increased, and the stratus and cirrus had dissipated, and 
small Cu covered about 25-30% of the sky.
TAKEOFF: 1445Z FSS T = 17.3, Td = 7.9 (jumped to 8.3 while he was talking) winds 
300/10, Alt 29.98
LANDING: 2030 FSS T = 22.4, Td = 8.1
Note:  Adj offset on both the fast ozones.  Also a CO2 cal done 

10 June 1994 Flight hours 3.3 (Hobbs) Pilot: EJD
SUMMARY: On this flight, a figure 8 pattern was flown over the Old Jack Pine 
site.
WEATHER: Mostly clear - Cu hum.
TAKEOFF: 2030Z FSS T = 22.2, Td = 7.8
LANDING: 2355Z FSS T = 23.3, Td = 5.9
Note:  On landing, the program had an overflow error message. 

11 June 1994 Flight hours 4.8 (Hobbs) Pilot: TLC
SUMMARY: The h, i, j "L" pattern was flown, coupled with circles at various 
altitudes over Old Jack Pine.
WEATHER: Cu building throughout the flight (10% coverage at the beginning, 
ending with about 40% coverage).  Areas of light precip around the OJP site.
TAKEOFF: 1610Z FSS T = 18.2, Td = 9.5, winds 300/5
LANDING: 2015Z FSS T = 20.8, Td = 9.4, winds 290/5 to 10
Notes: Original takeoff was at 0900L - TANS didn't come up, so TLC landed and 
reloaded vectors and rebooted the top board. 

12 June 1994 Flight hours 1.0 (Hobbs) Pilot: EJD
SUMMARY: Pitch cal 
WEATHER: 30-40% coverage of small Cu congestus
TAKEOFF: 1230Z winds 290/5, Alt 29.68 T = 11.7, Td = 9.3 Landing: 1315Z T = 
12.8, Td = 9.7
Notes: Weight = 1397.3 lbs; CG = 101.48 in. No ozone or CO2 for this flight.

12 June 1994 Flight hours 3.7 (Hobbs) Pilot: EJD
SUMMARY: The original plan called for Figure 8s over OJP; however, there was bad 
weather in the area, so EJD landed and discussed an alternate plan.  The 
decision was then to do the Old Aspen site. Figure 8s and 'Ls' were done over 
that site.
WEATHER: Cu building - clouds and rain over the area - mixed bag of weather
TAKEOFF: 1500Z (1st), 1615Z (2nd) FSS winds 330/5, Alt 29.68
LANDING: 1600Z(lst), 1845Z (2nd) FSS T=17.3, Td=8.6, winds 360/5G10, Alt 29.68
NOTE:  ***Gyros were off for whole flight*** 

12 June 1994 Flight hours 2.3 (Hobbs) Pilot: TLC
SUMMARY: Figure eights over Old Jack Pine
WEATHER: Building Cu throughout the flight..no precip for most of the time, some 
light precip near the end.
TAKEOFF: 1915Z FSS T=17.2, Td=8.6
LANDING: 2100Z
Notes:  2.5 nm around the tower has similar surface use as the tower -the rest 
is choppy and dissimilar (TLC in-flight note). Flight was terminated early 
because the data system 'crashed'.
*****GYROS WERE OFF THE WHOLE FLIGHT*****

20 July 1994 Flight time 5.1 hr (Hobbs) Pilot: TLC
SUMMARY: Pre-Test flight, 2 PRO's and 7 Candle Lake transects. Both the Electra 
and King Air flew the CL transects at the same time. Fast and slow O3 sensors 
installed after significant inprovements between IFC1-2. Now believed to be 
working.
WEATHER: Lots of rain last few days.  Forest fires have reduced visibility to 
about 5 miles.  The wind is from the north @10 kts.  At 1600 Cu started to 
build.  During the day buildup continued at a slow but persistent rate to around 
50% by the end of the flight.
PROBLEM - Flux gate had compass failed, now removed.  Some GPS ground station 
data lost around noon.  The NET did not work this flight due to a bad connection 
which was repaired after the flight.  File 07201834 had an unreadable block.  On 
test flight the gyro 10A fuse blew.  It was replaced with a 12A. Does this 
indicate a future problem?
NOTE: Average site altitude is about 1900 msl.  The gyro was cleaned before this 
flight to remove data "spikes". 

21 July 1994 Flight time 5.1 hours (Hobbs) Pilot: EJD
SUMMARY: 1 Pitch Cal, 7 Candle Lake transects, 1 Profile. Both the Twin Otter 
and King Air flew the grid transects at the same time. 
WEATHER: Excellent visibility today.  No Cu in the morning, built to less than 
10% in the afternoon. Wind calm initially, picked up considerably in the 
afternoon.  Turbulence very light in the morning picked up considerably in the 
afternoon.
PROBLEM - No problems noted during flight.  All instruments seemed to work well.

21 July 1994 Flight time 3.8 hours (Hobbs) Pilot: TLC
SUMMARY: 2-PRO's, 2 complete and 2 short Candle Lake transects.  The last CL 
transect was flown with the TO.  Flight direction was to west.  At Candle lake, 
the flight speed was reduced from 120 kts to 110 kts.  FE also flew the transect 
but ahead of FL & FT.  This was a "golden day" with 16 flights!
WEATHER: Clear sky all day!  Winds low and from 030
PROBLEM - Data system crashed caused early mission termination. 
NOTE: Since the winds are down the transect and lots of flight missions were 
flown, this may be a good day for "lake effects" boundary layer research.

22 July 1994 Flight time 1.7 hours (Hobbs) Pilot: EJD
SUMMARY: 2 Pitch Cals, 1 Candle Lake transect. Late evening, not much activity.
WEATHER: Clear over YPA, high clouds over CL transect.  Very little turbulence 
on CL run.
PROBLEM - No problems noted during flight.  All instruments seemed to work well.

23 July 1994 Flight time 4.7 hours (Hobbs) Pilot: TLC
SUMMARY: 2-PRO's and 6 Candle Lake transects.  The last CL transect was flown 
with the FK which operated at 200 AGL and 3500 MSL.  FT also flew the CL 
transect during transition from SS-OA to SS-OBS & OJP.
WEATHER: Flight started with clear skys but small Cu developed from delta to 
alpha.  By the end of the flight, the Cu was 60% at delta and 10% at alpha.  The 
wind was 330 at ?
PROBLEM - The O3 sensors were removed for this and all future flights.  The last 
two flights should have had good O3 data. 

23 July 1994 Flight time 2.6 hours (Hobbs) Pilot: EJD
SUMMARY: 2-PRO's and OJP site specific.
WEATHER: Flight started with cloudy skies > 50% cloud cover.  Turbulence was 
extremely rough. Terminated flight early due to extreme turbulence.

24 July 1994 Flight time 5.2 hours (Hobbs) Pilot: TLC
SUMMARY: 2-PRO's and 9 FLX L's under clear sky & light North winds.  The FT& FK 
flew the "Grid" during this flight.
WEATHER: Clear all day!  Winds light and from the north.

24 July 1994 Flight time 4.5 hours (Hobbs) Pilot: EJD
SUMMARY: 2-PRO's and 8 FLX L's under clear sky & light North winds.  The FT flew 
the L's at the same time as N3R.
WEATHER: Clear all day!  Winds light and from the north.  Some turbulence early 
in flight, decaying toward the end.

25 July 1994 Flight time 6.6 hours (Hobbs) Pilot: TLC
SUMMARY: Golden day #2. 2-PRO's and 9 CL FLX's under clear sky & calm winds.  
The FT worked site specifics while FK did CL at 200 AGL & 3500 MSL.  There are 
two flights where FT and FK were on the same transect at close to the same time.
WEATHER: Clear all day!  Winds very light and from the north.  Winds a little 
stronger to the east.
PROBLEM - Channel 4 power controller, which powers the gyros, blew a second 
fuse.  We are now running with a 14A fuse in this channel.  Power channels2 & 3 
are not working correctly.  They were disabled and bypassed with a switch.  The 
dew point has shown some problems on previous flights. The mirror was cleaned 
before this flight.  Audio flight notes were lost during last half of flight.

26 July 1994 Flight time 4.9 hours (Hobbs) Pilot: EJD
SUMMARY: Golden day #3. 1-Pitch cal, 1 PRO, and a bunch of OAS FLX's under clear 
sky & calm winds.
WEATHER: Clear all morning!  Winds very light and from the southwest. 
PROBLEM - No equipment problems noted.  All sensors appeared to be working well.

26 July 1994 Flight time 4.5 hours (Hobbs) Pilot: TLC
SUMMARY: 2-PRO's and 2 OJP asterisk under clear sky & calm winds.
WEATHER: Clear all day!  Winds very light.  Thin smoke/haze layer at ~8000.

27 July 1994 Flight time 1.0 hour (Hobbs) Pilot: EJD
SUMMARY: 1 Takeoff file, 1 Pitch cal, 1 river climb, 1 touch & go.
WEATHER: Haze layer at 4000' during Pitch cal.  Clear otherwise. PROBLEM - No 
equipment problems noted.  All sensors appeared to be working well.

27 July 1994 Flight time 5.9 hours (Hobbs) Pilot: TLC
SUMMARY: 2-PRO's and 5 FLX E-W grids under clear sky & low southerly winds.
WEATHER: Clear all day however there is a lot of smoke and haze!  Winds light.
PROBLEM - MFP clock set one day behind.  All data files corrected.  The last 
file, which included a PRO, TXI and STC, and its associated markers were lost.
NOTE: NSA is now the "hot" site; other aircraft operating in N.  The IRGA was 
cleaned before the flight.

28 July 1994 Flight time 5.8 hours (Hobbs) Pilot: EJD
SUMMARY: 2 PRO's and 8 Candle Lake flux runs under clear sky initially, rapid 
buildup of Cu to approx 40% for last 2 FLX runs.  WEATHER: Clear sky for first 4 
hours, last 2 hours rapid buildup of approx40% Cu and a thunderstorm near d on 
last FLX run. 

29 July 1994 Flight time 4.1 hours (Hobbs) Pilot: TLC
SUMMARY: 2 PRO's and 5 CL FLX under unsettled (variable cloud and some rain) 
conditions. 
WEATHER: Front passing through with associated unsetteled conditions.  Low small 
Cu (2000-2500) generated by overnight rain.  Stratus at 12000.  Winds are calm.

29 July 1994 Flight time Pilot: EJD
SUMMARY:  17 legs of Fig 8 pattern at Old Aspen
WEATHER: 

30 July 1994 Flight time Pilot: EJD
SUMMARY: 8 Candle Lake Flux transects

30 August 1994Flight hours 2.1 (Hobbs) 
SUMMARY: Shakedown flight - some problems encountered, i.e. no angles on first 
flight, but after rebooting the top card and reloading the antennae vectors, 
everything with respect to the TANS was up and operating correctly.  On the last 
attempt, however, the gyros were not on.
WEATHER: Mostly cloudy all day, with intermittent, moderate rain.  Conditions 
were not conducive for any good Candle Lake transects, or any site specific 
work.
NOTE: The Tp and Th pots were adjusted today, because the Tp was offscale low.  
The Th pots were accidentally adjusted (thinking they were the Tp's),but they 
were turned back and both the Tp and the Th look good now. 

31 August 1994 Flight time 5.8 hours (Hobbs)

SUMMARY: Candle Lake transects
WEATHER: Clear in the morning (up to about 10 a.m. local), then small Cu for the 
remainder of the day (coverage about 25%) 

1 September 1994 Flight time 6.2 hours (Hobbs)
SUMMARY: Candle Lake transects.
WEATHER: Clear in the morning, with Cu building around noon.  Coverage was no 
more than 25%.  By 1600L, most of the Cu had dissipated - coverage reduced to 
about 10% - more to the North.  On the transects there was Cu and haze.

3 September, 1994 Flight time 4.4 hours (Hobbs)
SUMMARY: Buttonhole patterns over Old Jack Pine.  Ground tracks of 030 and 210 
deg. 
WEATHER: Overcast on site for whole flight.  Moderate to strong crosswind. 

5 September 1994 Flight time 5.0 hours (Hobbs)
SUMMARY: Buttonhole patterns at Old Jack Pine and Black Spruce.
WEATHER: Clear and calm for takeoff, then around noon the clouds began to form 
and the winds picked up significantly.  Along the flight path, it was turbulent 
and windy.
NOTE:  Ozone filter came off sometime during flight

6 September 1994 Flight time 6.2 hours (Hobbs)
SUMMARY: Candle Lake transects
WEATHER: Clear and calm on takeoff.  Winds increased and changed directions in 
the early afternoon. Sky was clear all day with the exception of a few small Cu 
to the northeast (less than 5% coverage).  There was a gradual windshift at P.A. 
throughout the day.
NOTE:  Ozone filter came off sometime during flight (again). 

7 September 1994 Flight A Flight time 4.4 hours (Hobbs)
SUMMARY: 18 runs by OJP
WEATHER: Overcast in the morning with cirrus, clearing by mid-morning but with 
some cirrus still.

7 September 1994 Flight B Flight time 3.5 (Hobbs)
SUMMARY: Buttonhole pattern around the Old Aspen site.
WEATHER: Some thin high cirrus, but basically warm and clear.  Winds were 110-
120 at 10 most of the day (at P.A.)

8 September 1994 Flight A Flight time 4.4 hours (Hobbs)
SUMMARY: Grid pattern.
WEATHER: Clear, dry, warm, no wind.

8 September 1994  Flight B
SUMMARY: Grid patterns
WEATHER: Clear, dry, warm, almost no wind

9 September 1994 Flight time 3.4 hours (Hobbs)
SUMMARY: Buttonhole patterns over Old Jack Pine
WEATHER: Overcast with cirrus, slight wind, warm and humid 


11 September 1994 Flight time 5.4 hours (Hobbs)
SUMMARY: Candle Lake transects
WEATHER: Started out cloudy, then cleared in the P.A. area.  Cool day. EJD said 
the Candle Lake transect was overcast.
NOTE: Time of flight needs fixing.  When the data system was started, the 
computer clock showed 1536 and the GPS showed 1618. 

12 September 1994 Flight time 4.8 hours (Hobbs)
SUMMARY: Old Jack Pine and Old Aspen buttonhole patterns
WEATHER: The day started out overcast and rainy, but around 1030L, it started to 
clear; then Cu started to form around noon.  Cloud cover remained around 25% in 
the P.A. area.
NOTE: Computer time and GPS time were different by about 45 min. (GPS was 1738, 
computer was 1654.

13 September 1994 Flight time 5.0 hours (Hobbs)
SUMMARY: Site specific work over Old Black Spruce to coordinate with Larry 
Mahrt.  Then over to Old Jack Pine to allow Canadian TV to film some flybys.
WEATHER: Clear in the P.A. area until noon, then cirrus.  Over the OBS it was 
clear except for some cirrus, and over Old Jack Pine, basically clear 
conditions.  NOTE: TIMES ARE WRONG!! 

15 September 1994 Flight time 3.4 hours (Hobbs)
SUMMARY: IC with the Twin Otter over the Old Aspen site, then a couple of Candle 
Lake transects, and a pitch cal. 
WEATHER: Started out with some clouds, gradually cleared.  By 1430 (local) the 
sky had less than 5% coverage of small Cu, with some cirrus.

7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

Candle Lake transects covered an approximate 100-km transect; one pass by a 
tower was approximately 12 km; a grid leg was approximately 15 km; the "L" 
pattern ranged from 100 to 200 km.

The Long-EZ aircraft covered sites in the SSA.  The North American Datum 1983 
(NAD83) corner coordinates of the SSA are:

              Longitude    Latitude  
              ---------    --------  
Northwest     106.228 W   54.321 N 
Northeast     104.237 W   54.225 N 
Southwest     106.321 W   53.515 N 
Southeast     104.368 W   53.420 N 

The tower sites in the SSA include:

Site                 Longitude     Latitude      BOREAS X   BOREAS Y
--------------------------------------------------------------------
Old Black Spruce    105.11779 W  53.98717 N     385.012   348.646    
Old Jack Pine       104.69203 W  53.91634 N     413.526   343.226
Young Jack Pine     104.64529 W  53.87581 N     416.988   339.008
Fen                 104.61798 W  53.80206 N     419.527   330.991
Old Aspen           106.19779 W  53.62889 N     317.198   303.403


7.1.2 Spatial Coverage Map

None.

7.1.3 Spatial Resolution

The spatial resolution of the original data used in the flux computations is a 
function of the aircraft speed (50 m/s) and the digital recording rate (40 Hz).  
This translates to a basic sampling resolution of approximately 1 m for the 
Long-EZ.  However, there is significant natural geophysical variability 
associated with any turbulence measurement.  As a result, statistically 
significant covariance flux measurement requires space- or time-averaging.  The 
reported data values represent 3-km averages.  The basis for the utility of this 
short average is the Long-EZ's low flight altitude and fast-response data 
system.  The size of flux-transporting turbulence structure decreases (i.e., 
frequency increases) as the measurement altitude is reduced.  This tends to 
reduce the importance of intermittency, which adversely affects measurements 
made at higher altitudes.

7.1.4 Projection

Not applicable.
 
7.1.5 Grid Description

Not applicable.

7.2 Temporal Characteristics

These data were collected during the BOREAS IFCs in 1994.  The range of dates is 
from May 25 to September 15, 1994.

7.2.1 Temporal Coverage

There were typically two or three flights per day, with 4-5 hour duration each.
The days during which data were collected are:

May 25, 26, 27, 29, 31, 1994
June 1, 4, 6, 7, 8, 10, 11, 1994
July 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 1994
August 31, 1994
September 1, 3, 5, 6, 7, 8, 9, 11, 12, 13, 15, 1994

7.2.2 Temporal Coverage Map

None.

7.2.3 Temporal Resolution

The aircraft data were digitized at 200 Hz to allow an oversampling factor of 
five before recording at 40 Hz.

7.3 Data Characteristics 

Data characteristics are defined in the companion data definition file 
(mwlezflx.def).

7.4 Sample Data Record

Sample data format shown in the companion data definition file (mwlezflx.def).

8. Data Organization

8.1 Data Granularity

All of the AFM-01 NOAA/ATDD Long-EZ Aircraft Flux Data over the SSA are 
contained in one data set.

8.2 Data Format(s)

The data files contain numerical and character fields of varying length 
separated by commas.  The character fields are enclosed with single apostrophe 
marks.  There are no spaces between the fields. Sample data records are shown in 
the companion data definition file (mwlezflx.def).

9. Data Manipulations

9.1 Formulae

See Section 17.1.

9.1.1 Derivation Techniques and Algorithms

See Section 17.1.

9.2 Data Processing Sequence

Not available at this revision.

9.2.1 Processing Steps

See Section 17.1.

9.2.2 Processing Changes

None.

9.3 Calculations

9.3.1 Special Corrections/Adjustments

None.

9.3.2 Calculated Variables

None.

9.4 Graphs and Plots

None.

10. Errors

10.1 Sources of Error

None given.

10.2 Quality Assessment

10.2.1 Data Validation by Source

Care has been taken in the collection and analysis of the Long-EZ data. The wind 
measuring system is continually monitored for accuracy using techniques such as 
wind boxes, control input cases, and intercomparisons with other aircraft.  
Cospectral plots have been used to check the flux contributions at all 
wavelengths to ensure that they were not contaminated by inadequate compensation 
for aircraft motion.

10.2.2 Confidence Level/Accuracy Judgment

See Section 10.2.1.

10.2.3 Measurement Error for Parameters

Not available.

10.2.4 Additional Quality Assessments

Aircraft intercomparison was made by the investigators.

10.2.5 Data Verification by Data Center

BORIS staff loaded the data into the database and checked the values to make 
sure that they were within a reasonable range.

11. Notes

11.1 Limitations of the Data

None given.

11.2 Known Problems with the Data

See Section 6.2.

11.3 Usage Guidance

None given.

11.4 Other Relevant Information

None.

12. Application of the Data Set

This data can be used to create algorithms to relate boundary-layer processes to 
satellite-derived data.  

13. Future Modifications and Plans

None.

14. Software

14.1 Software Description

None.

14.2 Software Access

Not applicable.

15.   Data Access

15.1 Contact for Data Center/Data Access Information

These BOREAS data are available from the Earth Observing System Data and 
Information System (EOS-DIS) Oak Ridge National Laboratory (ORNL) Distributed 
Active Archive Center (DAAC). The BOREAS contact at ORNL is:

ORNL DAAC User Services
Oak Ridge National Laboratory
(865) 241-3952
ornldaac@ornl.gov
ornl@eos.nasa.gov

15.2 Procedures for Obtaining Data

BOREAS data may be obtained through the ORNL DAAC World Wide Web site at 
http://www-eosdis.ornl.gov/ or users may place requests for data by  
telephone, electronic mail, or fax.

15.3 Output Products and Availability

Requested data can be provided electronically on the ORNL DAAC's anonymous FTP 
site or on various media including, CD-ROMs, 8-MM tapes, or diskettes.

The complete set of BOREAS data CD-ROMs, entitled "Collected Data of the Boreal 
Ecosystem-Atmosphere Study", edited by Newcomer, J., et al., NASA, 1999, are 
also available.

16. Output Products and Availability

16.1 Tape Products

None.

16.2 Film Products

None.

16.3 Other Products

These data are available on the BOREAS CD-ROM series.

17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

Anderson, D.E., S.B. Verma, R.J. Clement, D.D. Baldocchi, and D.R. Matt. 1986. 
Turbulence spectra of CO2, water vapor, temperature and velocity over a 
deciduous forest. Agricultural and Forest Meteorology, 38:
81-99.

Auble, D.L. and T.P. Meyers. 1992.  An open path, fast response infrared H2O and 
CO2 instrument for atmospheric flux measurements. Boundary-Layer Meteorology, 
59, 243-256.

Crawford, T.L. and R.J. Dobosy. 1992.  A sensitive fast-response probe to 
measure turbulence and heat flux from any airplane. Boundary-Layer Meteorology 
59:257-278.

Crawford, T.L., R.J. Dobosy, R.T. McMillen, C.A. Vogel, and B.B. Hicks. 1996. 
Air-surface exchange measurement in heterogeneous regions: extending tower 
observations with spatial structure observed from small aircraft. Global Change 
Biology, 2:275-285.

Crawford, T.L. and R.T. McMillen. 1991.  Direct measurement of CO2 exchange to 
the ocean using an airborne eddy correlation system. In Proc. of the 7th 
Conference on Meteorological Observations and Instrumentation, New Orleans, LA, 
American Meteorological Society, Boston, MA. Preprint Vol. 2.5, pp. 42-45.

Crawford, T. L., R.J. Dobosy, and E. Dumas. Aircraft wind measurement 
considering lift-induced upwash and large attack angles. Boundary-Layer 
Meteorology (submitted).

Crawford, T.L. , R.T. McMillen and R.J. Dobosy. 1991. Description of a "generic" 
mobile platform using a small airplane and a pontoon boat. In Proc. of the 7th 
Conference on Meteorological Observations and instrumentation, New Orleans, LA, 
American Meteorological Society, Boston, MA. Preprint Vol. 2.4, pp. 37-41.

Crawford, T.L., T.T. McMillen, and R.J. Dobosy. 1993a.  Correcting airborne flux 
measurements for aircraft speed variation. J. Boundary-Layer Meteorology 66: 
237-245.

Crawford, T.L., T.T. McMillen, T.P. Meyers, and B.B. Hicks. 1993b.  The spatial 
and temporal variability of heat, mass, and momentum air-sea exchange in a 
coastal environment. J. Geophysical Research, 98:12,869-12,869.

Crawford, T.L., T.T. McMillen, and R.J. Dobosy. 1990. Development of a "Generic" 
Mobile Flux Platform with Demonstration on a Small Airplane. NOAA Technical 
Memorandum ERL ARL-184.

McMillen, R.T. and T.L. Crawford. 1991.  Direct measurement of CO2 exchange to 
the ocean using a ship mounted eddy correlation system. In Proc. of the 7th 
Conference on Meteorological Observations and Instrumentation, New Orleans, LA, 
American Meteorological Society, Boston, MA. Preprint Volume 2.6, pp. 46-50.

17.2 Journal Articles and Study Reports

Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment 
Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94). 

Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment 
Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96). 

Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere 
Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). 

Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere 
Study: 1996 Operations. NASA BOREAS Report (OPS DOC 96). 

Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. 
Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. 
Wickland. 1995. The boreal ecosystem-atmosphere study (BOREAS): an overview and 
early results from the 1994 field year. Bulletin of the American Meteorological 
Society. 76(9):1549-1577.

Sellers, P.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry, M.  
Ryan, K.J. Ranson, P.M. Crill, D.P. Lettenmaier, H. Margolis, J. Cihlar, J. 
Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D. Halliwell, D. Williams, B.  
Goodison, D.E. Wickland, and F.E. Guertin. 1997. BOREAS in 1997: Experiment 
Overview, Scientific Results and Future Directions. Journal of Geophysical 
Research 102 (D24): 28,731-28,770.

Webb, E. K., G. I. Pearman, and R. Leuning. 1980.  Correction of flux
measurements for density effects due to heat and water vapour transfer. 
Quarterly Journal of the Royal Meteorological Society, 106:85-100.

17.3 Archive/DBMS Usage Documentation

None.

18. Glossary of Terms

None.

19. List of Acronyms

    AFM     - Airborne Flux and Meteorology
    ASCII   - American Standard Code for Information Interchange
    ATDD    - Atmospheric Turbulence and Diffusion Division
    BOREAS  - BOReal Ecosystem-Atmosphere Study
    BORIS   - BOREAS Information System
    CD-ROM  - Compact Disk-Read-Only-Memory
    CG      - Center of Gravity
    DAAC    - Distributed Active Archive Center
    DGPS    - Differential Global Positioning System
    EOS     - Earth Observing System
    EOSDIS  - EOS Data and Information System
    GPS     - Global Positioning System
    GSFC    - Goddard Space Flight Center
    HTML    - HyperText Markup Language
    IFC     - Intensive Field Campaign
    IRGA    - Infrared Gas Analyzer
    NAD83   - North American Datum of 1983
    NASA    - National Aeronautics and Space Administration
    NOAA    - National Oceanic and Atmospheric Administration
    NSA     - Northern Study Area
    OA      - Old Aspen
    OJP     - Old Jack Pine
    OBS     - Old Black Spruce
    ORNL    - Oak Ridge National Laboratory
    PANP    - Prince Albert National Park
    PAR     - Photosynthetically Active Radiation
    POD     - Processed Output Data
    QA      - Quality Assurance
    SSA     - Southern Study Area
    URL     - Uniform Resource Locator

20. Document Information

20.1 Document Revision Date

Written: 01-Jan-1995
Last Updated: 13-Aug-1999

20.2 Document Review Date(s)

     BORIS Review:    14-June-1999
     Science Review: 

20.3 Document ID

20.4 Citation

Long-EZ aircraft flux data were collected by NOAA's Atmospheric Turbulence and 
Diffusion Division (ATDD).

20.5 Document Curator

20.6 Document URL

Keywords
---------
CARBON DIOXIDE
METHANE
BOUNDARY LAYER
WATER MIXING RATIO
OZONE
PHOTOSYNTHETICALLY ACTIVE RADIATION
AFM01_Moving_Window.doc
08/21/99