A Proposal (#GC00-277) to the National Oceanic and Atmospheric
Administration

Office of Global Programs

1100 Wayne Avenue, Suite 1225, Silver Spring, MD 20910-5603

(Project Area: Aerosols. Attn: Joel Levy, 301-427-2089 x111,
levy@ogp.noaa.gov)

for

**ACE-Asia Aerosol Radiative Effect Studies Using Airborne
Sunphotometer, Satellite and In-Situ Measurements**

Principal Investigator:

Philip B. Russell Date

Atmospheric Chemistry and Dynamics Branch

Earth System Science Division

NASA Ames Research Center, Moffett Field, CA 94035-1000

Telephone: 650-604-5404. Fax: 650-604-3625

prussell@mail.arc.nasa.gov

Co-Investigators:

Beat Schmid, Bay Area Environmental Research Institute (Tel.
650-604-5933, bschmid@mail.arc.nasa.gov)

Jens Redemann, Bay Area Environmental Research Institute (Tel.
650-604-6259, <jredemann@mail.arc.nasa.gov>)

John M. Livingston, SRI International (Tel. 650-604-3386,
<jlivingston@mail.arc.nasa.gov>)

Robert W. Bergstrom, Bay Area Environmental Research Institute (Tel.
650-604-6261, <bergstro@sky.arc.nasa.gov>)

Michael A. Box, University of New South Wales, Sydney, Australia (Tel.
61-2-697-4545, mab@newt.phys.unsw.edu.au)

Reviewed by:

R. Stephen Hipskind, Chief Date

Atmospheric Chemistry and Dynamics Branch

Authorizing Official:

Estelle P. Condon, Chief Date

Earth Science Division

NASA Ames Research Center

Budget requested from NOAA:

April 1, 2000 - March 30, 2001: \$159,100

April 1, 2001 - March 30, 2002: \$166,700

April 1, 2002 - March 30, 2003: \$173,200

Three Year Total: \$499,000

TABLE OF CONTENTS

[Page]{.underline}

LIST OF ILLUSTRATIONS i

ABSTRACT ii

LIST OF ACRONYMS ii

1\. RESULTS FROM PRIOR RESEARCH 1

2\. PROPOSED RESEARCH (STATEMENT OF WORK) 2

> 2.1 Rationale and Overall Goals 2
>
> 2.2 Relationship of the Proposed Research to Other Proposed
> Measurements and Analyses 3
>
> 2.3 ACE-Asia Goals, Overall Approach, and the 2001 Intensive Field
> Study 3
>
> 2.4 Satellite Measurements and Retrievals Relevant to ACE-Asia and the
> Proposed Research 5
>
> 2.5 Expected Role of Airborne Sunphotometry in ACE-Asia 6
>
> 2.6. Proposed Tasks 10
>
> 2.6.1 Year One 10
>
> 2.6.2 Years Two and Three 11
>
> 2.7. Schedule 13
>
> 2.8. References 13

3\. BUDGET 17

4\. STAFFING, RESPONSIBILITIES, AND VITAE 19

5\. CURRENT AND PENDING SUPPORT 28

ILLUSTRATIONS

  ---- -------------------------------------------------------------- -----
  1    Aerosol-induced change in net shortwave flux at tropopause     F1
       calculated from satellite maps of aerosol optical depth and    
       aerosol intensive properties from TARFOX.                      

  2    Channel wavelengths of Ames Airborne Tracking Sunphotometers   F2
       (AATS-6 and AATS-14) in relation to atmospheric spectra.       

  3    Latitude transects of aerosol optical depth and Ångström       F3
       exponent derived from the AATS-6 sunphotometer aboard the UW   
       C-131A, from ATSR-2, and from AVHRR.                           

  4    Aerosol optical thickness measured by sunphotometer (AATS-6)   F4
       aboard the C-131A aircraft and derived from MAS data as a      
       function of wavelength.                                        

  5    Scatter plot and spectra of aerosol optical depths obtained in F5
       ACE-2 by AATS-6 on the R/V Vodyanitskiy, AATS-14 on the        
       Pelican aircraft, and AVHRR on the NOAA-14 Satellite.          

  6    Profiles of aerosol optical depth and extinction at selected   F6
       AATS-14 wavelengths (380, 500, 864 and 1558 nm) measured in    
       ACE-2.                                                         

  7    Comparison of aerosol optical depth spectra for the marine     F7
       boundary layer during a Pelican flight in ACE-2.               

  8    Marine boundary layer aerosol size distributions from in situ  F8
       measurements and inverted from AATS-14 extinction spectra      
       measured on Pelican flight tf15 in ACE-2.                      

  9    Profiles of the columnar water vapor and water vapor density   F9
       measured in ACE-2 by AATS-14 and in situ sensor.               

  10   Scatter diagram of columnar water vapor calculated from        F10
       radiosonde measurements and from AATS-6 measurements during    
       ACE-2.                                                         

  11   Aerosol single-scattering albedo profiles determined for       F11
       TARFOX flight 1728 (July 17, 1996) by two techniques.          

  12   Comparison between aerosol-induced change in solar flux        F12
       derived from C-130 pyranometer measurements (data points) and  
       calculations (curves).                                         
  ---- -------------------------------------------------------------- -----

**ACE-Asia Aerosol Radiative Effect Studies Using Airborne
Sunphotometer, Satellite and In-Situ Measurements**

Principal Investigator: Philip B. Russell, NASA Ames Research Center

Proposed Cost: \$499,000, April 1, 2000-March 31, 2003

ABSTRACT

We propose to study the radiative effects of aerosols in the
Asia-Pacific region by making airborne sunphotometer measurements in the
ACE-Asia 2001 intensive field study and by conducting closure analyses
and integrated assessments that combine satellite and suborbital
measurements. Research in FY 2000 will focus on preparing for the 2001
intensive experiment by (a) developing analysis techniques for mixed
aerosols in the polluted and clean boundary layer and in elevated desert
dust layers, (b) investigating the sensitivity of satellite optical
depth retrieval techniques and predictions of aerosol-induced radiative
forcing to the properties of aerosols likely to be seen over the Western
Pacific and Asia, and (c) providing information about the location and
frequency of occurrence of the Asian aerosol plume to the ACE-Asia
planning process. The FY 2000 research will build on results for
American, European and African aerosols obtained in TARFOX and ACE-2.
Research in FY 2001-02 will include: (a) measuring aerosol optical depth
and extinction spectra along with water vapor column contents using an
Ames Airborne Tracking Sunphotometer in coordination with satellite, in
situ, and other remote measurements during the Intensive Observation
Period (IOP, late March-April 2001), (b) assessing the quality of the
combined ACE-Asia in situ and remote measurements and analysis models by
conducting closure studies, and (c) providing an initial assessment of
the radiative effects of aerosols over the Western Pacific and Asia by
applying and extending the techniques developed in FY 2000.

We envision the research proposed here to NOAA as part of a larger
ACE-Asia effort by the Ames airborne sunphotometer/satellite team. We
are seeking NASA and Navy support for the other components of this
overall effort. Specifically, this proposal requests support for
measurements by the 6-channel Ames Airborne Tracking Sunphotometer
(AATS-6) on the NCAR C-130. Separately, we are seeking NASA and Navy
support for measurements by our 14-channel unit (AATS-14) on the CIRPAS
Twin Otter. In addition, we have requested NASA support for modeling and
enhanced analyses using ACE-Asia and other data. Recognizing that both
funding and platform participation in ACE-Asia are uncertain, we are
currently maintaining the flexibility to assemble a research approach
that is most productive given the final levels of funding and
participation by others. If, for example, the NCAR C-130 does not
participate in ACE-Asia (because of aerosol inlet problems or funding
limitations), we propose that the funding requested here be applied to
either (a) AATS-6 measurements on an ACE-Asia ship (as we did in ACE-2)
or (b) AATS-14 measurements on the Twin Otter. Regardless of the
measurement configuration ultimately chosen, we will pursue our overall
goal of assessing the radiative effects of aerosols in the Asia-Pacific
region to the extent possible with the suborbital and satellite
measurement data sets and the analysis funding available.

**ACRONYMS**

  -------------- --------------------------------------------------------
  AA-SEC         ACE-Asia Survey and Evolution Component (ACE-Asia 2001
                 Intensive Field Study

  AATS-6         6-channel Ames Airborne Tracking Sunphotometer

  AATS-14        14-channel Ames Airborne Tracking Sunphotometer

  ACE            Aerosol Characterization Experiment

  ADEOS          Advanced Earth Observing Satellite

  ASTER          Advanced Spaceborne Thermal Emission and Reflection
                 Radiometer

  ATSR           Along-Track Scanning Radiometer

  AVHRR          Advanced Very High Resolution Radiometer

  BOREAS         Boreal Ecosystem-Atmosphere Study

  CERES          Clouds and the Earth's Radiant Energy System

  CIRPAS         Center for Interdisciplinary Remotely Piloted Aircraft
                 Studies

  EOS            Earth Observing System

  ERBE           Earth Radiation Budget Experiment

  FIFE           First ISLSCP Field Experiment

  GACP           Global Aerosol Climatology Program

  GLI            Global Imager

  GOES           Geostationary Operational Environmental Satellite

  HAPEX-Sahel    Hydrologic-Atmospheric Pilot Experiment in the Sahel

  IGAC           International Global Atmospheric Chemistry Program

  INDOEX         Indian Ocean Experiment

  IOP            Intensive Observation Period

  ISLSCP         International Satellite Land Surface Climatology Project

  LITE           Lidar In-space Technology Experiment

  OES            Office of Earth Science

  MAS            MODIS Airborne Simulator

  MDAR           Modeling and Data Analysis Research Program

  MISR           Multi-angle Imaging Spectro-Radiometer

  MODIS          Moderate-resolution Imaging Spectroradiometer

  MOPITT         Measurements of Pollution in the Troposphere

  NCAR           National Center for Atmospheric Research

  PATMOS         Pathfinder Atmospheric Data Sets \[from AVHRR\]

  PICASSO-CENA   Pathfinder Instruments for Cloud and Aerosol Spaceborne
                 Observations -- Climatologie Etendue des Nuages et des
                 Aerosols

  POLDER         Polarization and Directionality of the Earth's
                 Reflectances

  SAFARI         Southern African Fire-Atmosphere Regional Science
                 Initiative

  SAGE           Stratospheric Aerosol and Gas Experiment

  SCAR-B         Smoke, Clouds And Radiation experiment in Brazil

  SeaWiFS        Sea-viewing Wide-Field-of-view Sensor

  SEC            Survey and Evolution Component \[of ACE-Asia\]

  SSFR           Spectral Solar Flux Radiometer

  TARFOX         Tropospheric Aerosol Radiative Forcing Observational
                 Experiment

  TOMS           Total Ozone Mapping Spectrometer

  TRACE-A        Transport and Chemistry Near the Equator-Atlantic

  TRACE-P        Transport and Chemical Evolution over the Pacific

  TRMM           Tropical Rainfall Measurement Mission

  UNOLS          University-National Oceanographic Laboratory Systems
  -------------- --------------------------------------------------------

**ACE-Asia Aerosol Radiative Effect Studies Using Airborne
Sunphotometer, Satellite and In-Situ Measurements**

**1. RESULTS FROM PRIOR RESEARCH**

As required by the guidelines in the Program Announcement, this section
briefly summarizes results of related projects supported by NOAA and
other agencies. More extensive descriptions of selected results and
their relevance to the proposed research are given in Sections 2.4 and
2.5. As requested, each paragraph head gives award title, funding
agency, award number (if available), period of award, and total award.

**Improved Exploitation of Field Data Sets to Address Aerosol
Radiative-Climatic Effects and Development of a Global Aerosol
Climatology, NASA RTOP #622-44-75-10, 10/98-9/01, \$525,000.** This
ongoing award supports tasks on (a) Airborne Sunphotometer Optical Depth
Data Quality Checks, (b) Mixed Aerosol Optical Modeling, (c) Automated
Size Distribution Retrievals, (d) Size Distribution Comparisons and
Closure Studies, (e) Water Vapor/Aerosol Interactions and Satellite
Retrievals, and (f) Flux Change/Radiative Forcing Studies. Vertical
profiles of derived single scattering albedos and flux changes for
TARFOX aerosols have been described in a journal paper by Redemann et
al. (2000b); an example of the single scattering albedo results is in
Section 2.5. Other results include calculations of the humidity
dependence of single scattering albedo of sulfate-coated soot particles
and a comparison of aerosol single scattering albedos determined in
TARFOX and ACE-2 by a variety of techniques. These results and the
remainder of this research are in the prepublication stage, but early
results have been presented at several conferences.

**ACE-2 Ship Sunphotometry and Integrated Analyses, NOAA Office of
Global Programs, Order No. NA97AANAG0163, 5/97-4/00, \$265,000.** This
award supported (a) ACE-2 CLEARCOLUMN coordination by Dr. Russell, (b)
Measurements by the 6-channel Ames Airborne Tracking Sunphotometer
(AATS-6) on the ACE-2 ship, (c) Special AATS-6 calibrations and
intercomparisons, and (d) Analyses combining the AATS-6 data with
satellite and other suborbital data. Results are described in four
journal publications led by our team (Bergstrom and Russell, 1999;
Livingston et al., 2000; Russell and Heintzenberg, 2000; Schmid et al.,
1999), plus several others we coauthored (e.g., Durkee et al., 2000;
Pilewskie et al., 2000). Selected results are summarized in Sections 2.4
and 2.5 of this proposal.

**ACE-2 Airborne Sunphotometer Measurements, Naval Postgraduate School,
11/96-10/97, \$129,000.** This award supported preparation and
calibration of the 14-channel Ames Airborne Tracking Sunphotometer
(AATS-14) and measurements by AATS-14 on the Pelican aircraft in ACE-2.
Twenty-one flights were made, including four Langley-plot calibration
flights. Data were analyzed using the award listed below; selected
results are shown in Section 2.5.

**TARFOX and ACE-2 Integrated Analyses, NASA RTOP #622-44-10-10,
10/96-9/99, \$450,000.** This award supported (a) TARFOX analysis
coordination by Dr. Russell, (b) TARFOX airborne sunphotometer
integrated analyses, (c) Analyses of AATS-14 measurements on ACE-2
Pelican flights, and (d) Related ACE-2 integrated analyses. Results are
described in four journal publications led by our team (Russell et al.,
1999a,b; Redemann et al., 2000a, Schmid et al., 2000), a PhD thesis
(Redemann, 1999), and several journal papers we coauthored (e.g., Tanre
et al., 1999; Veefkind et al., 1999; Ferrare et al., 2000a,b; Collins et
al., 2000; Gasso et al., 2000; Welton et al., 2000). Selected results
are summarized in Section 2.5 of this proposal.

**TARFOX Airborne Sunphotometry, NASA RTOP #460-43-46-10, 5/95-9/96,
\$61,000.** Results: Optical depth spectra were measured with AATS-6 on
18 flights of the UW C-131A, and demonstration measurements were made
with AATS-14 on 5 flights of the Pelican. Flights were coordinated with
overpasses by four satellites, flights by ER-2 and C-130 aircraft, and
surface lidar and radiometer measurements. Results of early closure
analyses were described by Hegg et al. (1997). A new expression was
derived for computing aerosol-induced flux changes (i.e. radiative
forcing) as a function of solar zenith angle. Results of the new
expression were compared to two-stream and adding-doubling results, and
all three techniques were used to estimate flux changes expected in
column closure experiments. This local radiative forcing was shown to be
15-100 times as large as global-average results (Russell et al., 1997).

**2. PROPOSED RESEARCH (STATEMENT OF WORK)**

**2.1 Rationale and Overall Goals**

Aerosol effects on atmospheric radiation remain a major uncertainty in
understanding past and present climates and in predicting the future
climate. Recent experiments designed to reduce this uncertainty (e.g.,
TARFOX, ACE-2, and INDOEX) have produced important advances but in the
process have emphasized remaining questions that must be answered
(Russell et al., 1999a; Raes et al., 2000; Russell and Heintzenberg,
2000; Ramanathan, 1999). For example, there is now a renewed
appreciation for the variety and complexity of actual aerosols and for
the importance of capturing the salient features of this complexity
when, for example, relating predictions of global aerosol chemical
transport models (CTMs) to satellite-derived optical depths and
radiative forcings. There is also an increased appreciation for the
effect of absorbing aerosols on the vertical thermal structure of the
atmosphere, and hence on convection, cloud formation and persistence,
and surface evaporation (e.g., Russell et al., 1999b; Ramanathan, 1999).
This is in contrast to the emphasis of several years ago on the effect
of nonabsorbing aerosols on top-of-atmosphere or top-of-troposphere
radiation budgets.

The results of recent experiments have not only emphasized the
complexity of the problem but have also demonstrated, via measurements
and models, that the effects of aerosols are too large to be ignored.
For example, results from TARFOX, ACE-2, and INDOEX have demonstrated
that aerosols in persistent plumes from America, Europe, Africa, and
India produce seasonal top-of-atmosphere radiative flux changes that
exceed those of anthropogenic greenhouse gases (several W m^--2^) and
daily surface radiative flux changes that are larger still (several tens
of W m^--2^) (Bergstrom and Russell, 1999; Russell et al., 1999b;
Meywerk and Ramanathan, 1999; Ramanathan, 1999; Satheesh et al., 1999).
These surface flux changes affect not only convection and clouds but
also sea-surface evaporation rates and probably regional hydrology
(e.g., Huebert et al., 1999a,b; Ramanathan, 1999).

The aerosol plume emanating from eastern Asia over the Pacific is
already one of the world's major aerosol plumes, and it is expected to
increase rapidly over the next several decades as a result of Asian
economic development. It differs in several important ways (see below)
from the American, European, African, and Indian plumes studied in
TARFOX, ACE-2, and INDOEX. Hence, it is probably the most important
continental aerosol plume to study now (Huebert et al., 1999a,b).

The overall goal of the proposed research is to assess the radiative
effects of the aerosols in this Asia-Pacific regional plume. The
approach will be to make airborne sunphotometer measurements in the
ACE-Asia 2001 Intensive Observation Period (IOP, late March-April) in
coordination with satellite and other suborbital measurements and to
conduct closure analyses and integrated assessments that combine the
satellite and suborbital measurements. In FY 2000 our research will
focus on preparing for the 2001 IOP by:

\(a\) Developing analysis techniques for mixed aerosols in the polluted
and clean boundary layer and in elevated desert dust layers,

\(b\) Investigating the sensitivity of satellite optical depth retrieval
techniques and predictions of aerosol-induced radiative forcing to the
properties of aerosols likely to be seen over the Western Pacific and
Asia, and

\(c\) Providing information about the location and frequency of
occurrence of the Asian aerosol plume to the ACE-Asia planning process.

Our FY 2000 research will build on results for American, European and
African aerosols obtained in TARFOX and ACE-2. Research in FY 2001-02
will include:

\(a\) Measuring aerosol optical depth and extinction spectra along with
water vapor column contents using an Ames Airborne Tracking
Sunphotometer in coordination with satellite, in situ, and other remote
measurements during the IOP (March-April 2001),

\(b\) Assessing the quality of the combined ACE-Asia measurements and
analysis models by conducting extensive closure studies, and

\(c\) Providing an initial assessment of the radiative effects of
aerosols over the Western Pacific and Asia by applying and extending the
techniques developed in FY 2000.

**2.2 Relationship of the Proposed Research to Other Proposed
Measurements and Analyses**

This proposal requests support for measurements with the 6-channel Ames
Airborne Tracking Sunphotometer (AATS-6) on the NCAR C-130 in the 2001
intensive field study, plus certain limited analyses, as summarized
above and specified in Sections 2.4-2.6. We envision the research
proposed here to NOAA as part of a larger ACE-Asia effort by the Ames
airborne sunphotometer/satellite team. Separately, we are seeking NASA
and Navy support for the other components of this overall effort,
including measurements by our 14-channel unit (AATS-14) on the CIRPAS
Twin Otter. Recognizing that both funding and platform participation in
ACE-Asia are uncertain, we are currently maintaining the flexibility to
assemble a research approach that is most productive given the final
levels of funding and participation by others. If, for example, the NCAR
C-130 does not participate in ACE-Asia (because of aerosol inlet
problems or funding limitations), we propose that the measurement
funding requested here be applied to either (a) AATS-6 measurements on
an ACE-Asia ship (as we did in ACE-2) or (b) AATS-14 measurements on the
Twin Otter.

We have also submitted a proposal, "Satellite-Sunphotometer Studies of
Aerosol, Water Vapor and Ozone Roles in Climate-Chemistry-Biosphere
Interactions", to the NASA Modeling and Data Analysis Research (MDAR)
Program. That proposal includes no funds for measurements, instead
requesting funding for modeling and analysis of data acquired in field
experiments such as SAFARI-2000 and ACE-Asia. The specific tasks
proposed to NASA MDAR are: (1.1) Optical Modeling of Smokes and Other
Aerosols Expected in SAFARI 2000, (1.2) Ozone-Aerosol Separation
Algorithm Refinement and Simulations, (1.3) Water Vapor Retrieval
Refinement, (1.4) Aerosol Column Size Distribution and Mass Retrieval
Algorithm Development, (1.5) Quick-Look Analyses and Comparisons to
Satellite Data, (1.6) Preliminary Aerosol Radiative Effect Calculations,
(2.1) Satellite Validation Studies, (2.2) Update of Aerosol Optical
Models, Including Mineral Dusts, (2.3) Aerosol Evolution and Budget
Studies, (2.4) Aerosol Chemical-Physical-Optical Closure Studies, (2.5)
Aerosol Radiative Effect Calculations, and (2.6) Integrated Analyses and
Assessments. Funding requested from NASA MDAR is \$225K, \$267K, and
\$309K in FY00, FY01, and FY02, respectively; to date the proposal has
not been selected for funding.

In an effort to limit the cost of the current proposal (which includes
both measurements and analyses) the analyses proposed here are very
limited compared to the MDAR list above. If the MDAR proposal is funded,
the analyses proposed here will benefit from the MDAR analyses. If the
MDAR proposal is not funded, the analyses proposed here can still
produce a published research product, especially from the combined
analysis efforts in FY2000 and FY2002. Efforts in FY2001 will be limited
primarily to measurements (including preparations) and initial data
reduction and quality checks (including preliminary closure
comparisons).

Regardless of the sunphotometer/aircraft measurement configuration
ultimately chosen, we will pursue our overall goal of assessing the
radiative effects of aerosols in the Asia-Pacific region to the extent
possible with the suborbital and satellite measurement data sets and the
analysis funding available.

Sections 2.3-2.5 summarize ACE-Asia's goals and overall approach, as
well as the expected role of satellite and sunphotometer measurements in
relation to in situ and other remote measurements. Section 2.6 describes
the proposed research tasks.

**2.3 ACE-Asia Goals, Overall Approach, and the 2001 Intensive Field
Study**

The Asian Pacific Regional Aerosol Characterization Experiment
(ACE-Asia) is the fourth in a series of aerosol characterization
experiments organized by the International Global Atmospheric Chemistry
Program (IGAC). Each ACE is designed to integrate suborbital and
satellite measurements and models so as to reduce the uncertainty in
calculations of the climate forcing due to aerosol particles (Huebert et
al., 1999b). ACE-Asia focuses on aerosol outflow from Asia to the
Pacific basin because (1) Asian anthropogenic emissions and mineral dust
are very different from the environments of previous ACE experiments,
and (2) Expected increases in Asian emissions have the potential to
cause large changes in radiation budgets, cloud microphysics, and
hydrological output over the coming decades.

The goals of ACE-Asia are to determine and understand the properties and
controlling factors of the aerosol in the anthropogenically modified
atmosphere of Eastern Asia and the Northwest Pacific and to assess their
relevance for radiative forcing of climate (Huebert et al., 1999b).
Subsidiary objectives are to:

1\. Determine the physical, chemical, and radiative properties of the
major aerosol types in the Asian Pacific region, determine their state
of mixing, and investigate the relationships among these properties.

2\. Quantify the physical and chemical processes controlling the
evolution of aerosols in the Asian Pacific region and in particular
their physical, chemical, and radiative properties.

3\. Develop procedures to extrapolate aerosol properties and processes
from local to regional and global scales, and assess the regional direct
and indirect radiative forcing by aerosols in the Eastern Asia and
Northwest Pacific region.

ACE-Asia will include a network of ground stations operated over the
2000-2004 timeframe, with intensive, multiplatform field studies to
focus on specific objectives. The first intensive field study
(previously called the Survey and Evolution Component, AA-SEC) is
described in the overview by Huebert et al. (1999a). Planned for
March-April 2001, it has the following goals (Huebert et al., 1999b):

• determine the physical, chemical and radiative properties of the
aerosol in the ACE-Asia region and assess the vertical, regional and
temporal (diurnal to multi-day) variability of these properties,

• assess the major processes controlling the oxidation mechanisms of
aerosol precursor gases and the formation, evolution and deposition of
aerosol particles,

• quantify the direct radiative effect of the combined natural and
anthropogenic aerosol in the ACE-Asia study area,

• refine satellite aerosol retrievals in the ACE-Asia region so that
satellite observations can be used to obtain a high temporally and
spatially resolved assessment of the clear-sky direct effect of aerosols
on radiative transfer,

• improve the parameterizations used in chemical transport models in
order to obtain more accurate regional distributions of aerosol
properties, and

• test and refine radiative transfer models used with chemical transport
models to calculate direct radiative forcing by aerosol particles.

To address these goals flight plans and ship operations will be directed
to sample regional aerosol features (e.g. dust layers, urban and
industrial plumes) under different synoptic meteorological patterns and
at various distances from shore. Quantifying aerosol direct radiative
forcing will require the integration of multiple measurement and
modeling approaches. Radiative transfer models, coupled with chemical
transport models, will be used to partition the radiative effects of
aerosols between the natural and anthropogenic components and thus
quantify aerosol direct radiative forcing. These models must rely on
accurate parameterizations of aerosol properties. Satellites will be
used to assess the temporal and spatial variability in aerosol columnar
extinction. These observations can be used to assess the direct
radiative effect of the combined natural and anthropogenic aerosol.
However, the algorithms used for these retrievals must again rely on
accurate parameterizations of aerosol properties. In-situ measurements
of aerosol chemical, physical, and radiative properties and radiative
fluxes throughout the vertical column can be used to directly quantify
the radiative effect of the combined natural and anthropogenic aerosol
and provide the parameterizations needed for satellite retrievals and
models. The combination of in-situ measurements, columnar extinction
measurements (surface-based, air and space-borne radiometers), radiative
flux measurements and models will produce an overdetermined data set
that can be used to evaluate the combined uncertainty of the models and
measurements used to assess the direct radiative forcing of aerosols in
the ACE-Asia study area.

The AA-SEC omnibus proposal to NSF (Huebert et al., 1999a) describes a
plan to address these questions using three US mobile platforms (the
NCAR C-130, the CIRPAS Twin Otter, and a NOAA or UNOLS ship) plus 1-2
enhanced ground stations working in coordination with ships, aircraft,
lidars, and surface sites from a variety of nations (e.g., Japan, Korea,
China, and Taiwan). The operations base is tentatively chosen as Iwakuni
Marine Base, near Hiroshima in southern Japan. Efforts will be made to
coordinate some AA-SEC flights with the NASA TRACE-P program, which will
be focusing on photochemistry in Asian outflow at about the same time,
using measurements on the NASA DC-8 and P-3. If possible AA-SEC will
coordinate some observations with an airborne simulator for the
PICASSO-CENA spaceborne lidar.

As in previous ACEs, satellite data products will be used by ACE-Asia
both in realtime to plan and direct flights and for post-campaign
analyses. For example, ACE-Asia flights that study the plumes of desert
dust emanating from Asia will be guided by satellite observations that
identify locations of maximum dust concentrations and areas where
concentration gradients can most easily be studied. In flights designed
to study aerosol evolution, satellite observations of the decay of
backscatter by the continental plume will be used to identify regions
where removal mechanisms seem especially effective. As amplified in the
following section, our proposed research will use satellite data in
exploratory studies before the 2001 intensive and in more complete
studies during and after the intensive, and it will also contribute to
the validation and refinement of satellite retrievals.

**2.4 Satellite Measurements and Retrievals Relevant to ACE-Asia and the
Proposed Research**

Satellite measurements of Earth-reflected radiance have been used to
derive both aerosol optical depths and aerosol effects on radiative
fluxes. As recently summarized by King et al. (1999), several approaches
have been used to retrieve aerosol optical depth (AOD) from radiances or
reflectances measured by a wide range of satellite sensors (e.g., AVHRR
on NOAA-7, -9, -11, -14, POLDER and OCTS on ADEOS, ATSR-2 on ERS-2,
SeaWiFS on OrbView-2). Mishchenko et al. (1999) have shown that these
optical depth retrievals depend strongly on cloud screening methods and
radiometer calibration, and, to a lesser extent, on models of aerosol
single scattering albedo , scattering phase function *P*~a~andsurface
reflectance. Although a complete treatment requires numerical multiple
scattering techniques (e.g., Mishchenko et al., 1999), the dependence on
and *P*~a~ can be illustrated by using the linearized single scattering
approximation (e.g., Stowe et al., 1997; King et al., 1999),

![](media/image1.pct), (1)

in which *L*~a~ is the aerosol contribution to the satellite-measured
radiance, ~0~ and ~v~ are sun and view zenith cosines, and is scattering
angle.

Aerosol effects on radiative fluxes and budgets can also be derived from
satellite measurements in several ways. One approach is to use satellite
flux products, which are obtained by using directional and spectral
models to convert the radiance(s) at the satellite viewing angle and
wavelength band(s) to directionally and spectrally integrated fluxes
(e.g., Ramanathan et al., 1989). For example, Minnis et al. (1993) used
monthly-averaged ERBE-retrieved fluxes to show that, in August 1991, the
Pinatubo volcanic aerosol increased upwelling fluxes by 10 W m^-2^ in
the 5°N to 5°S band and 4 W m^--2^ in the 40°N to 40°S band. More
recently, Ramanathan (1999) and Satheesh and Ramanathan (1999) used
CERES data from the TRMM satellite to show that the tropospheric aerosol
observed in INDOEX increased diurnal mean upwelling fluxes by \~10 W
m^--2^ or more.

Another approach to obtaining aerosol-induced flux changes from
satellite data is to combine satellite-retrieved AOD with other aerosol
and surface properties in a radiative transfer calculation. For example,
Figure 1 shows the aerosol-induced change in net shortwave flux at the
tropopause obtained in this way by Bergstrom and Russell (1999). They
used the AVHRR/NOAA AODs reported by Husar et al. (1997) for the period
July 1989-June 1991 in combination with aerosol intensive properties
determined primarily in TARFOX. Those intensive properties, which
included optical depth wavelength dependence and spectra of single
scattering albedo and scattering asymmetry parameter across the solar
wavelength range (0.3 to 4 m), were also checked against initial
properties from ACE-2. Comparing frames e and f of Figure 1 shows that
changing from 0.9 to 1.0, [while keeping AOD and all other properties
unchanged]{.underline}, increased the computed annual regional average
flux change by 37% (from -3.5 to -4.8 W m^--2^). However, Eq. (1) shows
that, when starting with a given satellite radiance *L*~a~, changing (or
*P~a~*) also changes retrieved AOD. Hence, a fully consistent treatment
starting with satellite radiance *L* (rather than, e.g., the Husar et
al. AOD values used by Bergstrom and Russell) must take this dependence
into account. The resulting dependences are best calculated with a
multiple scattering code but can be illustrated using the diurnal
average flux-change approximation of Haywood and Shine (1995), Chylek
and Wong (1995), and Russell et al. (1997),

, (2)

in which ~a~*F* is the aerosol-induced change in upwelling flux at the
top of atmosphere, *F*~T~ is the solar constant, *T* is atmospheric
transmission, *A*~C~ is cloud fraction, ~a~ is the aerosol upscatter
fraction, and *R*~S~ is surface albedo. Substituting (1) in (2) yields

. (3)

Changing aerosol complex refractive index *m* to change can produce even
larger changes in *P*~a~() at satellite view angles. For example, Stowe
et al. (1997) report that increasing *m~i~* from 0 to 0.01 in the model
of Ignatov et al. (1995) decreased by only 10% while simultaneously
decreasing *P~a~*() by \~30%, thus decreasing their product by \~37% and
increasing *AOD~SAT~* by \~59% (cf. Eq. (1)).

In the proposed research we will start with the approach of Bergstrom
and Russell (1999) and then explore more advanced and self-consistent
ways of deriving effects of the Asia-Pacific regional aerosol on
radiative fluxes. That is, we will start in FY2000 with
satellite-retrieved AOD data sets and retrieval algorithms that already
exist or are being developed. Examples include the 1989-91 AVHRR
retrievals of Husar et al. (1997), other AVHRR retrievals by Durkee et
al. (2000) and Nakajima and Higurashi (1998), 1996-97 results from OCTS
and POLDER on ADEOS, 1994-99 AVHRR data available in PATMOS data sets,
or the 1985-88 AVHRR/NOAA 9 preliminary aerosol climatology of
Mishchenko and Geogdzhayev (1999), developed as part of the Global
Aerosol Climatology Program. To the extent possible we will ascertain
the aerosol models used in deriving those AODs. We will then use those
aerosol models together with the derived AODs in radiative transfer
calculations of aerosol-induced flux changes ~a~*F* at various altitudes
(e.g., top of atmosphere, tropopause, surface). The calculations will
use the generalized two-stream model used by Bergstrom and Russell
(1999), the Fu-Liou broadband radiative transfer model (Fu and Liou,
1992; 1993) used by Redemann et al. (2000b), and/or the radiative
perturbation approach (Box and Trautman, 1994; Sendra and Box, 1999)
pioneered by the group of Co-I Michael Box. Next we will investigate the
effect, on both retrieved AOD and calculated ~a~*F*, of realistic
changes in the aerosol models. The changed aerosol models will be based
both on published results for aerosols expected in the ACE-Asia area and
on measurements during ACE-Asia. An analogous approach for Indian Ocean
aerosols has been used by Rajeev et al. (2000). Our goal is to derive by
2002 a self-consistent set of satellite-based AOD and ~a~*F* fields that
reflect aerosol measurements made in ACE-Asia. We will also examine ERBE
and CERES flux data products (analogous to the approaches of Minnis et
al. and Ramanathan \[see above\]) for aerosol effects, and we will
compare them to our results obtained from satellite AOD data.

We will study aerosol radiative effects over both land and ocean. Data
from the new EOS Terra platform, launched December 18, 1999, will aid in
this regard. Terra carries the sensors MODIS, MISR, MOPITT, ASTER, and a
new CERES system to complement that already flying on TRMM. The
multi-angle measurements of MISR, and the improved spectral resolution
of both MODIS and MISR, will increase chances of accurate AOD retrievals
over land. TOMS and TOMS-like sensors on several platforms (e.g., Earth
Probes, and the new GLI on ADEOS II) will provide regional maps of both
column ozone and aerosol index over land and water. POLDER on ADEOS II
will provide aerosol measurements that benefit from its polarization
sensing capability, helping to extend retrievals over land. SeaWiFS and
MODIS data products will also include aerosols in regions impacted by
Asian continental outflow over both the Pacific and Indian Oceans.

All these satellite products will require validation over a wide range
of conditions. Although validation studies for the sensors listed above
will be conducted prior to the ACE-Asia 2001 intensive (e.g., in
SAFARI-2000 in southern Africa), the intensive will provide new
conditions and data sets with which to extend those validation studies.
For example, the yellowish soil dust aerosol layers emanating from Asia
are known to have different spectral absorption characteristics than the
red-brown Sahara dust (e.g., Nakajima et al., 1989); however, these
differences are not well quantified. ACE-Asia measurements during yellow
dust plume events should provide important new validation data sets for
EOS Terra and TOMS aerosol and ozone products, and for water-leaving
radiance products from SeaWiFS as well as MODIS. The ACE-Asia suborbital
measurements will also be essential in extending data outside the
satellite overpass times and locations.

**2.5 Expected Role of Airborne Sunphotometry in ACE-Asia**

The AA-SEC Science and Implementation Plan (Huebert et al., 1999a)
specifies aerosol optical depth measurements as part of the minimum
requirement for both surface and airborne platforms, and it includes an
Ames tracking sunphotometer as part of the "Highest Priority --
Essential" payload for the NCAR C-130 and part of the recommended
payload for the CIRPAS Twin Otter. Some of the reasons for these
inclusions are summarized below. The AA-SEC Plan (Huebert et al., 1999a)
also includes a variety of schematic C-130 and Twin Otter fight plans,
each designed to address specific questions. For example, they include
flights at several altitudes across the edges of elevated dust layers
and upwind and downwind of urban-industrial plumes. Some flight patterns
include legs with the Twin Otter flying near the surface under a plume
while the C-130 overflies the plume with a downward-looking lidar. In
this section we outline how airborne sunphotometer measurements and
analyses could contribute to such flights and their analyses, using
examples from recent studies with AATS-6 and -14 data. For reference,
Figure 2 shows AATS-6 and -14 channel wavelengths in relation to
atmospheric spectra.

As noted above, satellite validation is an essential element of
ACE-Asia, because of the expected major role of satellite measurements
in assessing regional, seasonal, and interannual aerosol effects.
Airborne sunphotometer measurements flown along transects near the land
or ocean surface in ACE-Asia can provide aerosol optical depth spectra
useful for validating products from simultaneous satellite overflights.
This is illustrated in Figure 3, which shows a comparison of airborne
sunphotometer (AATS-6), AVHRR, and ATSR-2 data acquired in TARFOX over
the Atlantic Ocean when the UW C-131A flew across a gradient of aerosol
optical depth between latitudes 37-39 N (Veefkind et al., 1999). The
flight path was chosen using half-hourly GOES images to locate the
aerosol gradient. Comparing Figures 3a and 3b shows that the ATSR-2
retrieval reproduces the sunphotometer-measured optical depth gradient
better than the AVHRR retrieval. Comparing 3c and 3d shows how the
ATSR-2 retrieval also matches the sunphotometer-determined Angstrom
exponent better than AVHRR. In the ACE-Asia 2001 intensive GOES or other
realtime satellite imagery could be used to design flight legs across
the gradient from plume core to edge during a subsequent satellite
overpass (by, e.g., EOS Terra carrying MODIS, MISR, and CERES). AATS
optical depth spectra on legs flown near the surface would provide
validation data for comparisons such as those in Figure 3.

Figure 4 shows other comparisons from TARFOX, when AATS-6 on the UW
C-131A underflew the MODIS Airborne Simulator (MAS) on the NASA ER-2
(Tanre et al., 1999). These comparisons focus on the wavelength
dependence of optical depth and illustrate how the magnitude of optical
depth affects the success of the MAS retrieval. Specifically, the good
agreement in wavelength dependence and magnitude obtained when optical
depth is relatively large (\>0.2 for \<1 m) degraded when optical depth
decreased below \~0.05 (causing MAS-measured radiance from the aerosol
to decrease relative to radiance from the ocean surface). Establishing
such limits and uncertainties is a major reason for validation studies.
In the ACE-Asia 2001 intensive they could be conducted for a variety of
aerosol types and conditions, over different types of land surfaces
(e.g., densely vs. sparsely vegetated), the ocean, and on transects
spanning land and ocean.

Figure 5 illustrates how a change in aerosol type can affect the
validity of satellite retrievals. The scatter diagram in Figure 5a
(Durkee et al., 2000) compares AVHRR-retrieved aerosol optical depth
(AOD) at 630 and 860 nm with AOD measured in ACE-2 by a variety of
sunphotometers on land, ship, and aircraft. Data points with AOD\>0.25
are cases where an elevated layer of Sahara dust was present; those with
AOD\<0.25 had no Sahara dust. For all 23 cases shown the AVHRR standard
error of estimate is 0.025 for 630 nm wavelength and 0.023 for 860 nm.
Note that in the dust-containing cases (AOD\>0.25), the AVHRR-retrieved
AODs are biased low compared to sunphotometer optical depths (by amounts
ranging from 0.01 to 0.08) whereas in the dust-free cases
AVHRR-retrieved values are biased slightly high. Figure 5b compares AOD
spectra for a case from Figure 5a where dust was present; Figure 5c is
the analogous comparison for a dust-free case (Livingston et al., 2000;
Schmid et al., 2000). These cases show clearly the change in bias of the
AVHRR retrieved values between dust-free and dust-containing cases,
especially at 860 nm. Possible reasons for this change include
differences between the wavelength-dependent single scattering albedos
and phase functions of the Sahara dust and those assumed in the AVHRR
retrieval (Durkee et al., 2000), plus the height of the absorbing dust
aerosols (e.g., Quijano et al., 1999). In the ACE-Asia 2001 intensive
field study, sunphotometer underflights of different types of aerosol
(e.g., desert dust vs. industrial emissions) could provide analogous
tests of the validity of satellite products as a function of aerosol
type. Vertical profile flights by the sunphotometer aircraft would
provide simultaneous in situ data on aerosol physicochemical properties,
helping to complete the picture.

In comparisons like those in Figures 4 and 5 it is important to
understand all significant error sources for each measurement technique
and to quantify their combined effect in realistic error bars. The error
bars on the AATS data result from a comprehensive error analysis
(Russell et al., 1993) and include contributions from uncertainties in
calibration, signal measurement, Rayleigh scattering, absorbing gases
(O~3~, O~4~, H~2~O, NO~2~), airmass, and diffuse light. They are
produced routinely in our analyses and will be in the proposed work.

AA-SEC flight plans (Huebert et al., 1999a) also call for the C-130 and
Twin Otter to ascend from near the surface through the aerosol layers
aloft while collecting in situ data on aerosol size distribution,
chemistry, light scattering and absorption. Figure 6 illustrates the
ability of the airborne sunphotometers to measure vertical profiles of
multiwavelength aerosol optical depth and extinction during such
aircraft profiles (Schmid et al., 2000). The case shown, obtained in
ACE-2, documents an elevated layer of Sahara dust (\~2-3.5 km asl)
overlying a very clean layer (\~1-2 km asl) and a moderately polluted
marine boundary layer (\<\~1 km asl). Note that the wavelength
dependence of extinction is very different in the marine and Sahara
layers, with extinction nearly independent of wavelength between 380 and
864 nm in the Sahara layer, owing to the relatively large particles
there. The ACE-Asia 2001 intensive is expected to reveal many
occurrences of analogous layering, with different layers often having
different sources and characteristics. Airborne sunphotometry combined
with simultaneous in situ physicochemical-optical measurements will
provide a rich data set for modeling such diverse, vertically structured
aerosols and understanding their impact on satellite retrievals.

Closure studies that examine the degree of consistency between
sunphotometer measurements, in situ measurements, and the models that
link them are an important source of information on the strengths and
weaknesses of the examined measurement and modeling techniques. A
typical result from such a closure study is shown in Figure 7 (Schmid et
al., 2000). The data were obtained in ACE-2 when the Pelican aircraft
ascended through a marine boundary layer, carrying AATS-14 and a variety
of in situ samplers. The optical depth spectrum labeled "Caltech OPC"
was obtained by combining in situ size spectra with refractive index
models obtained from size-resolved chemical composition measurements at
a nearby surface site (which were consistent with size-integrated
chemistry measured on the aircraft). The optical depths labeled
"Neph+PSAP" were obtained by combining nephelometer measurements of
aerosol light scattering (at 1 or 3 wavelengths) with absorption
measurements from an absorption photometer.

The result in Figure 7 is typical in that the optical depth spectrum
measured by sunphotometer (AATS-14) exceeds that calculated from the in
situ measurements. Although some of the error bars overlap (e.g., the
OPC-derived optical depth bars with the others), the fact that
sunphotometer-measured optical depths nearly always exceed in situ
derived optical depths in ACE-2, TARFOX, and other comparisons (e.g.,
Clarke et al., 1996; Hegg et al., 1997; Hartley et al. 2000; Kato et
al., 1999; Remer et al., 1997) points to a systematic phenomenon that
bears explaining. Possible reasons include (1) loss of semivolatile
aerosol material (e.g., organics) during in situ sampling that is not
accounted for in the in situ analyses (e.g., Eatough et al., 1996), and
(2) light absorption by a gas along the sunphotometer viewing path that
is not accounted for in the sunphotometer analyses (e.g., Halthore et
al., 1998). Explaining this persistent difference could have fundamental
implications for our understanding of aerosol properties and/or
radiative transfer. The ACE-Asia 2001 intensive could present excellent
opportunities for studying this question, if one or more aircraft carry
enhanced instrumentation for measuring organic aerosols and spectral
flux radiometers (Pilewskie et al., 1998) that can help to distinguish
aerosol absorption from gas absorption (see below).

At the same time the AATS data could provide a test of the
backscatter-to-extinction ratios and other assumptions used to derive
optical depths from the C-130 lidar. Such comparisons could be a
valuable precursor to validation flights for PICASSO-CENA conducted
after its launch (scheduled for 2003). This would yield AATS vertical
profiles of multiwavelength extinction (as in Figure 6) for comparison
to lidar profiles (as was done, e.g., in ACE-2 by Schmid et al., 2000;
and Welton et al., 2000). Comparisons of the profiles of sunphotometer
extinction, lidar backscatter, and in situ size distribution can yield
best-fit values of complex refractive index and single-scattering albedo
for each sampled layer, as demonstrated by Redemann et al. (1998,
2000a,b) with PEM-West and TARFOX measurements (see Figure 11). These
values could be compared to single scattering albedos from the in situ
scattering and absorption measurements (see below) and to complex
refractive indices from the in situ chemistry measurements, taking into
account the local humidity and effects of aerosol hygroscopicity.

Another type of closure study relating in situ and sunphotometer
measurements compares in situ size distributions with those retrieved
from sunphotometer optical depth spectra. Such a comparison is shown in
Figure 8 (Schmid et al., 2000). Within the optically effective diameter
range (\~0.22 to 8 m) the AATS-14 retrieved distribution replicates the
main features of the in situ distribution, although for some diameters
(\~0.7 to 3 m) the AATS-14 retrieved distribution exceeds the in situ
values. This exceedence is in accord with the systematic difference
between sunphotometer and in situ optical depth spectra noted above.

The size distribution retrieval in Figure 8 used the constrained linear
inversion program of King et al. (1978) and a refractive index model for
the polluted marine boundary layer aerosol recommended by Tanre et al.
(1997). In the proposed research new aerosol optical models appropriate
to the ACE-Asia aerosols will be developed and used both in the King
inversion procedure and in a new procedure based on the recent results
of Remer et al. (1998) regarding persistent features of multimodal
aerosols. Sunphotometer optical depth spectra will also be provided to
Co-Investigator Dr. Michael Box, whose group will analyze them to
extract aerosol size information. Techniques they have developed for
this purpose include table look-up, analytic inversion in the anomalous
diffraction approximation, singular function theory, and analytic
eigenfunction theory (e.g., Box et al., 1992; Viera and Box, 1987). They
have recently developed a covariance matrix method to accurately
separate the aerosol contribution in trace gas channels. This same
technique is currently being extended to develop better techniques to
obtain aerosol size information, as well as the direct extraction of
aerosol surface area and volume.

Sunphotometer-derived column or layer size distributions could be
validated by comparisons to in situ data from profile flights (as, e.g.,
in Figure 8), and used when underflying plumes to document changes in
overlying aerosol effective radius, surface area, and mass. This
information should be valuable in aerosol evolution studies (e.g., to
see whether sedimentation modifies the dust size-distribution in a
predictable way) and reduce the need for aircraft profiles, which take
flight time away from horizontal legs. However, deriving accurate
information on aerosol size, surface area, and mass from sunphotometer
optical depth spectra requires algorithms that incorporate
size-dependent effective refractive indices that are appropriate to the
aerosol on the sunphotometer viewing path. Incorporation of simultaneous
AATS data on water vapor will be investigated as a means of accounting
for possible humidification effects on refractive index (which will be
different in sulfate layers and dust layers, for example).

Water in both vapor and condensed phases has a strong influence on
radiative transfer and on aerosol size and composition. Given the
horizontal contrast in water vapor sources among continental and marine
parts of airmass trajectories, one can expect important variations in
water vapor and associated aerosol changes in ACE-Asia. AATS-6 and
AATS-14 measure water vapor transmission in the 940-nm band (cf. Figure
2), thus permitting simultaneous retrievals of water vapor column
contents and aerosol optical depth spectra. This ability to measure
water vapor and aerosols on a common viewing path should be useful in
studying aerosol-water vapor interactions. The water vapor sensing
ability is illustrated in Figure 9, which compares an AATS-14 water
vapor profile to simultaneous in situ measurements (Schmid et al.,
2000). Figure 10 shows a scatter plot comparing AATS-6 water vapor
columns with those obtained by integrating radiosonde profiles in ACE-2
(Livingston et al., 2000). The rms difference, 0.10 g cm^--2^ over a
range of 1.5 to 3.3 g cm^--2^, is typical of other comparisons we have
made. For example, in the fall 1997 Water Vapor Intensive Observation
Period (IOP) of the Atmospheric Radiation Measurement (ARM) program,
AATS-6 water vapor column retrievals agreed within 0.11 g cm^--2^ with
results from the Global Positioning System (2 locations), 3 microwave
radiometers, radiosondes, and two other sunphotometers. The range of
water vapor column amounts during the IOP was 1 to 5 g cm^--2^.

ACE-Asia planning documents stress the importance of realtime or
quick-turnaround data analyses and open data access as means of
maximizing the scientific return from the measurements. Both AATS-6 and
AATS-14 have demonstrated this in previous campaigns like TARFOX and
ACE-2, where they produced realtime color plots of aerosol optical depth
spectra that were used in flight direction and planning, as well as in
daily science team meetings (which included comparisons to satellite
products). With adequate preparation, this capability could be extended
in the ACE-Asia 2001 intensive to include realtime or quick-turnaround
displays of water vapor and ozone overburdens, as well as of the
effective radius, volume, and/or mass of the overlying aerosol column.
The latter would be useful for observing the evolution of aerosol size
when, for example, following a plume downwind, or for mapping
cross-plume column masses. Acquiring analogous plume-integrated sizes
and masses with in situ sensors would require time-consuming vertical
profiling (thus reducing time available for horizontal surveys) and
would subject the aerosols to the sampling challenges that are
especially difficult on a vertically profiling aircraft. Providing the
above-described realtime displays requires the development and testing
of algorithms before the campaign, as described in the proposal to NASA
MDAR mentioned in Section 2.2.

The AA-SEC Plan (Huebert et al., 1999a) also includes a variety of
schematic C-130 and Twin Otter fight plans, each designed to address
specific questions from the list above. For example, they include
flights at several altitudes across the edges of elevated dust layers
and upwind and downwind of urban-industrial plumes. Some flight patterns
include legs with the Twin Otter flying near the surface under a plume
while the C-130 overflies the plume with a downward-looking lidar. This
will permit comparisons between AATS-14 extinction profiles (like those
shown in Figure 6) and backscatter and/or extinction profiles from the
lidar. Both AATS-6 and AATS-14 have participated in such comparisons
previously. In ACE-2, for example, Schmid et al. (2000) and Welton et
al. (2000) compared lidar and airborne sunphotometer profiles in a
Sahara dust layer over the Izana observatory in the Canary Islands. They
got good agreement when the lidar analysis used a
backscatter-to-extinction ratio derived from simultaneous ground-based
sunphotometry. In TARFOX, Redemann et al. (2000a) derived best-fit
complex refractive indices in aerosol layers by comparing simultaneous
profiles of backscatter from an ER-2 lidar profile with profiles of
extinction and relative size distribution from AATS-6 and optical
particle counters on the UW C-131A. By combining the best-fit complex
refractive indices with the relative size distribution profiles,
Redemann et al. (2000b) then produced profiles of aerosol single
scattering albedo (SSA). Figure 11 shows an example result, compared to
the SSA profile obtained by Hartley et al. (2000) using simultaneous
measurements of aerosol scattering, absorption, and scattering
humidification factor.

Combining airborne sunphotometer optical depth profiles with radiative
flux profiles is a potentially powerful way to determine the absorption
properties (hence SSA) of the ambient aerosol, unperturbed by sampling
processes. This is illustrated by the TARFOX results shown Figure 12
(Russell et al., 1999b). The data points show the aerosol-induced
decrease in downwelling solar flux measured by pyranometers on the UK
C-130 during two descents into aerosol layers over the Atlantic Ocean,
plotted versus broadband aerosol optical depth derived from occulted
pyranometer measurements (Hignett et al., 1999). (The absorbing gas and
Rayleigh components have been removed from both the flux change and the
optical depth using, e.g., concurrent water vapor measurements.) The
curves show calculations of the expected flux change, based on aerosol
size distributions retrieved from AATS-6 sunphotometer measurements on
the UW C-131A, a real refractive index spectrum for aqueous sulfate, and
a range of imaginary refractive indices giving the midvisible
single-scattering albedos (550 nm) shown. Comparing the data points and
curves shows that the best-fit value of (550 nm) is \~0.9; chi-square
analyses using the error bars on the pyranometer optical depths and flux
changes (the cross in Figure 12) yield (550 nm)=0.895±0.025 and
0.905±0.045 for July 25 and 27, respectively.

In the ACE-Asia 2001 intensive field study careful measurements by well
calibrated and controlled flux radiometers on the same aircraft as
AATS-6 or AATS-14 could permit analogous flux-change studies. For
example, Dr. Peter Pilewskie of NASA Ames is proposing to put his Solar
Spectral Flux Radiometers (SSFR, Pilewskie et al., 1998) on the C-130
and/or Twin Otter. Combining such spectral flux measurements with AATS
optical depth measurements would permit much improved flux change
studies. The spectral resolution of SSFR and AATS-6 or -14 will permit
the type of flux change analysis shown in Figure 12 to be accomplished
in a wide range of narrow (5 nm) spectral bands. This will permit, for
example, solving for SSA as a function of wavelength. It will also aid
in identifying absorption features that might be due to unknown gas
spectroscopy, rather than aerosols. And it will help to identify
artifacts that might be caused by cloud fragments or surface albedo
effects. The measurements in Figure 12 were made over the ocean during a
cloud-free period to minimize such effects. This will be done in
ACE-Asia also; however, the fine spectral resolution in the SSFR flux
measurements may allow the measurements to be extended over a uniform
land surface, and may also allow some relaxation in the cloud-free
criterion. This will be investigated. These types of measurements will
also be carried out when an absorbing aerosol is carried over a uniform
stratus deck; the underlying cloud reflectivity maximizes aerosol
absorption in such a case. Asian dust outflow over coastal stratus in
ACE-Asia could provide such an opportunity.

**2.6. Proposed Tasks**

For the funding requested in Section 3 we will provide the necessary
personnel, equipment, and facilities, and will perform the following
tasks.

**2.6.1 Year One**

**2.6.1.1 Task 1.1: Satellite Data Acquisition.** Acquire a
representative suite of satellite data on aerosol optical depths in the
ACE-Asia area. Consider results derived from AVHRR by several techniques
(e.g., Husar et al., 1997; Durkee et al., 2000; Nakajima and Higurashi,
1998) and also results from OCTS and POLDER on the ADEOS satellite,
SeaWiFS on the OrbView-2 satellite, and ATSR-2 on the ERS-2 satellite.
Coordinate with the investigators who are performing the satellite
retrieval intercomparision for GACP.Investigate the TOMS absorbing and
nonabsorbing aerosol data products for applicability.

**2.6.1.2 Task 1.2: Preliminary Aerosol Optical Modeling.** Survey
existing optical models of aerosols in the polluted and clean marine
boundary layer and in elevated dust layers; select those that seem most
applicable to Asian outflow aerosols. Use previous (e.g., ACE-2, TARFOX)
results for single scattering albedo, size distribution, and optical
depth wavelength dependence determined by several techniques. Check
results for consistency with size-resolved chemical composition and
hygroscopicity measurements, and use trajectory analysis to help
estimate soil dust chemical composition. Use shell-and-core calculations
to investigate the dependence of aerosol absorption on relative
humidity. For each aerosol type, provide spectra of extinction, single
scattering albedo, scattering asymmetry parameter, and scattering phase
function at satellite measuring angles. For soil dust aerosols, extend
these spectra into the terrestrial infrared (wavelength \> 4 microns).

**2.6.1.3 Task 1.3: Satellite Sensitivity Studies.** Compare the phase
functions and single scattering albedos obtained in Task 1.2 with those
assumed in the satellite retrievals used in Task 1.1. Provide a
preliminary estimate of how using the more realistic properties would
change the retrieved optical depths.

**2.6.1.4 Task 1.4: Preliminary Estimates of Aerosol-Induced Radiative
Flux Changes.** Combine the intensive optical properties from Task 1.2
with the optical depths from Tasks 1.1 and 1.3 to estimate radiative
flux changes caused by Asian aerosols over the Pacific. Include flux
changes at top of atmosphere, tropopause, and surface. For soil dust
aerosols include shortwave and longwave effects.

**2.6.1.5 Task 1.5: Estimates of the location and frequency of
occurrence of the Asian aerosol plume.** From the data obtained in Task
1.1 and results of Tasks 1.3 estimate the year-to-year variation in the
location and frequency of occurrence of the Asian plume in the ACE-ASIA
measurement area. Provide the information to the ACE-ASIA science team
for planning purposes.

**2.6.2 Years Two and Three**

**2.6.2.1 Task 2.1: AATS-6 Integration and Test Flights on the NCAR
C-130.** We will work with NCAR personnel to integrate AATS-6 on the
C-130 and will demonstrate science data acquisition on test flights.

**2.6.2.2 Task 2.2: Pre- and Post-mission Calibrations.** We will
conduct pre- and post-mission calibrations of the water vapor and
aerosol channels of AATS-6 at a mountaintop site (e.g., Mauna Loa
Observatory) in \~February and \~May 2001. Efforts will be made to
conduct the calibrations with other ACE-Asia sunphotometers, to permit
intercomparisons.

**2.6.2.3 Task 2.3: Airborne Sunphotometer Measurements.** We will make
measurements of aerosol optical depth and water vapor columns using
AATS-6 on the NCAR C-130 during the ACE-Asia intensive in March-April
2001. We will provide quick-look data products (plots, electronic files)
to the Science Team within 24 hours after each flight. We will provide
calibrated, reanalyzed data products within nine months following the
post-mision calibration.

**2.6.2.4 Task 2.4: Intercomparisons, Validations, and Integrated
Closure Analyses.** Depending on our level of funding, we will perform
selected intercomparisons and closure analyses of the type described in
Sections 2.4 and 2.5. Data will be exchanged, archived, and released to
the scientific community according to ACE-Asia protocols (Huebert et
al., 1999b) and formats.

**Satellite Validation Studies.** Comparisons of the type shown in
Figures 3-5 will be made between satellite data products and airborne
sunphotometer aerosol optical depth spectra, wavelength dependence
parameters (e.g., the Angstrom exponent), and water vapor column
contents. The degree of agreement or disagreement found will be
quantified in terms of root-mean-square differences and mean biases, all
as functions of wavelength, aerosol type, and viewing condition
(including surface type and solar and satellite angles). The airborne
sunphotometer data can be used to assess the degree of variability
within satellite pixels (including variations between surface
sunphotometer sites), which may be particularly important near localized
sources or plume edges or for measurements in broken cloud fields.
Aerosol models assumed in the satellite retrievals will be compared to
the aerosol models used or developed in Task 1.2, and also to aerosol
properties determined from in situ measurements in ACE-Asia. Where
significant differences in assumed and actual aerosol properties are
found, examples of adjusted satellite products can be produced, using
the single scattering albedo and phase function of the actual aerosols.
Possible shape effects for soil dust and sea salt aerosols can be
investigated (e.g., Mishchenko et al., 1997; Kahn et al., 1997), as well
as effects of the vertical distribution of absorbing and nonabsorbing
aerosols (e.g., Clark et al., 1997; Quijano et al., 1999).

**Update of Aerosol Optical Models, Including Mineral Dusts.** The
aerosol optical models used or developed in Task 1.2 will be updated
using the suborbital measurements (e.g., in situ chemical, physical and
optical, airborne sunphotometer, ground Sun/sky radiometer, and air and
ground lidar). Areas of emphasis can include quantifying characteristic
differences between African (reddish-brown) and Asian (yellowish) soil
dust aerosols (e.g., Sokolik and Toon, 1999; Sokolik, 1999) and
capturing changes that occur during downwind evolution of various
aerosols (including dusts and smokes) as a result of agglomeration of
different particles (e.g., soot, sulfates, nitrates), condensation of
water and/or organic vapors, and photochemical reactions outside and
inside of clouds. Particular emphasis will be placed on quantifying the
wavelength- and humidity-dependent single scattering albedo of realistic
multicomponent aerosols, since this parameter is so important in
determining both AOD~SAT~ and aerosol radiative impacts on climate
(including top-of-atmosphere forcing, surface forcing, stability
changes, and cloud changes).

**Aerosol Evolution and Budget Studies.** If our proposal to NASA MDAR
(see Section 2.2) is funded we will combine the algorithms developed in
that work with airborne sunphotometer data acquired while underflying
plumes and hazes in downwind and crosswind transects to study how
aerosol sizes and masses evolve during downwind transport, and how
various sources contribute to regional mass budgets. Efforts will be
made to use the airborne sunphotometer water vapor measurements to
estimate the condensed water content of overlying aerosols and thereby
choose the most appropriate aerosol optical property models to use in
the algorithms that retrieve size distribution and mass from optical
depth spectra.

**Aerosol Chemical-Physical-Optical Closure Studies.** In addition to
the satellite validation studies described above we plan to conduct
closure studies that evaluate the mutual consistency of the
sunphotometer data products, other remote, radiometric, and in situ
measurements, and the models that link them. Examples include:

• Comparisons (as in Figure 7) between optical depth spectra measured by
airborne sunphotometer and calculated from in situ measurements of size
distribution, chemical composition (including condensed water), light
scattering, and absorption on the same aircraft profile,

• Comparisons (as in Figure 8) between size distributions retrieved from
airborne sunphotometer extinction or optical depth spectra and obtained
from in situ measurements (after correcting for such sampling effects as
evaporation, inlet size cutoffs, and composition-dependent calibration
factors),

• Comparisons between sunphotometer optical depths and those obtained
from lidar profiles using the backscatter-to-extinction values assumed
in the lidar analyses. These backscatter-to-extinction ratios will also
be compared to those derived from in situ measurements and the aerosol
models developed in Tasks 1.1 and 2.2. Effects of nonsphericity in soil
dust and seasalt aerosols will be considered, since lidar backscatter is
sensitive to nonsphericity.

• (If the ACE-Asia proposal by Dr. Pilewskie is funded) Comparisons
between radiative flux changes measured by SSFRs (Pilewskie et al.,
1998) and calculated from simultaneously measured aerosol and gas
properties. These comparisons will be analogous to those in Figure 12,
with the advantage that both the flux changes (from SSFR) and the
optical depths (from AATS-6 or --14) will be available in narrow
wavelength bands. Hence best-fit aerosol single scattering albedos
derived from analyses like those in Figure 12 will also be available as
a function of wavelength.

• Comparisons of aerosol single scattering albedos derived by a variety
of techniques, including (1) comparing lidar backscatter, sunphotometer
extinction, and in situ size distribution profiles (e.g., Redemann et
al., 2000a), (2) combining in situ measurements of aerosol light
scattering, absorption, and hygroscopicity (e.g., Hegg et al., 1997;
Hartley et al., 2000), (3) flux-change comparisons (e.g., Russell et
al., 1999b), and (4) the optical modeling in Tasks 1.2 and this task. A
comparison of results from techniques (1) and (2) is illustrated in
Figure 11.

The above examples are only illustrative. Our experience has been that
participation in multiplatform, multiagency campaigns like ACE-Asia
presents many opportunities for comparisons and closure studies, some of
which, though very important, were not anticipated in advance. These
closure studies, which typically entail collaborations among several
groups using disparate measurement and modeling techniques, germinate
during pre- and post-campaign science team meetings as well as during
the campaigns. We expect that this will be the case during the proposed
research.

**2.6.2.5 Task 2.5: Aerosol Radiative Effect Calculations.** We will
expand on the radiative transfer modeling carried out in Task 1.4. by
incorporating the aerosol fields actually observed by satellite during
ACE-Asia. In addition, aerosol parameters obtained from the
multi-instrument closure studies in Task 2.4 and those derived from the
advanced mixed aerosol optical models outlined in Tasks 1.2 and 2.4 will
be used to drive the radiative transfer codes. Our goal is to derive by
2002 a self-consistent set of satellite-based AOD and ~a~*F* fields that
reflect aerosol measurements made in ACE-Asia. We will also examine ERBE
and CERES flux data products (analogous to the approaches of Minnis et
al. and Ramanathan \[see above\]) for aerosol effects, and we will
compare them to our results obtained from satellite AOD data.

**2.7. Schedule**

2000 C-130/AATS-6 integration planning, Boulder, CO (\~May)

> Acquire suite of Asia-Pacific satellite optical depth data (May-Sep)
>
> Choose & develop Asia-Pacific aerosol optical models (May-Dec)
>
> Western Pacific Geophysics Meeting, Tokyo (27-30 Jun)
>
> IGARSS 2000, Honolulu, HI (24-28 Jul)
>
> Investigate effect of model aerosol properties on satellite optical
> depths (Jul-Nov)

Estimate radiative flux changes (Jul-Dec)

> ACE-Asia Science Team Meeting, Hawaii (Fall)
>
> 2001 Intensive Field Study Planning Meeting, Iwakuni Marine Base,
> Japan (\~Sep/Oct)

2001 C-130/AATS-6 integration & test flights, Boulder, CO (\~Jan)

> Pre-mission sunphotometer aerosol/water vapor calibration, Mauna Loa
> Observatory, HI (Feb)
>
> ACE-Asia intensive deployment, Iwakuni Marine Base, Japan (25 Mar-30
> Apr)
>
> Post-mission sunphotometer aerosol/water vapor calibration, Mauna Loa
> Observatory, HI (May)
>
> Data reduction and initial closure tests (May-Dec)
>
> ACE-Asia Science Team Meeting and Data Workshop (\~Oct?)

ACE-Asia Special Session at Scientific Conference (primarily individual
analyses; \~Dec?)

2002 Update optical models using ACE-Asia results (Jan-Aug)

> Continuing closure studies (Jan-Dec)

Radiative flux change studies (Jan-Dec)

> ACE-Asia Special Session at Scientific Conference (including
> integrated analyses; \~May?)

ACE-Asia Science Team Meeting and Data Workshop (\~Sep?)

2003 ACE-Asia Special Journal Issues

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**3. BUDGET**

**4. STAFFING, RESPONSIBILITIES, AND VITAE**

Dr. Philip Russell will be Principal Investigator. As such, he will
supervise the work, lead the planning, and participate in the
measurements and analyses, as well as selected presentations and
publications. He will be responsible for the completion of the work
within budget and schedule. Mr. John Livingston and Drs. Beat Schmid and
Jens Redemann will use AATS-6 in the proposed measurements and
participate in its preparation. They and Dr. Robert Bergstrom will
participate in the development and use of algorithms and models and will
lead and/or participate in specified data analyses, presentations, and
publications. Ames will furnish additional engineering and technical
personnel necessary to maintain, operate, and repair the instrumentation
before, during, and after the calibrations and field measurements.

Dr. Michael Box of the University of New South Wales (UNSW) in
Australia, along with selected members of his group (including Dr. Gail
Box), will analyze AATS optical depth and extinction spectra using their
innovative algorithms, with the goal of deriving particle size
information, surface area and volume, from which radiative forcing
calculations will also be performed. Dr. Box is seeking Australian
support for this collaborative research, and no support for the UNSW
effort is requested in this proposal.

**(a) Philip B. Russell**

**Abbreviated Curriculum Vitae**

B.A., Physics, Wesleyan University (1965, Magna cum Laude; Highest
Honors). M.S. and Ph.D., Physics, Stanford University (1967 and 1971,
Atomic Energy Commission Fellow). M.S., Management, Stanford University
(1990, NASA Sloan Fellow).

Postdoctoral Appointee, National Center for Atmospheric Research
(1971-72, at University of Chicago and NCAR). Physicist to Senior
Physicist, Atmospheric Science Center, SRI International (1972-82).
Chief, Atmospheric Experiments Branch (1982-89), Acting Chief and Acting
Deputy Chief, Earth System Science Division (1988-89), Chief,
Atmospheric Chemistry and Dynamics Branch (1989-95), Research Scientist
(1995-present), NASA Ames Research Center.

Currently, Member, Science Team for Global Aerosol Climatology Project
(GACP; Investigation Title: Improved Exploitation of Field Data Sets to
Address Aerosol Radiative-Climatic Effects and Development of a Global
Aerosol Climatology). Member, Science Teams for SAGE II and SAGE III
(satellite sensors of stratospheric aerosols, ozone, nitrogen dioxide,
and water vapor). Primary responsibilities: analyses of volcanic aerosol
properties and effects, development of the SAGE III Aerosol Algorithm
Theoretical Basis Document (ATBD), and experiment design and data
analyses to validate the satellite measurements.

Previously, NASA Ames Associate Fellow (1995-96, awarded for excellence
in atmospheric research).

Previously, Co-coordinator for the CLEARCOLUMN component of the Second
Aerosol Characterization Experiment (ACE-2) of the International Global
Atmospheric Chemistry (IGAC) Project. Coordinator for IGAC's
Tropospheric Aerosol Radiative Forcing Observational Experiment
(TARFOX). Convenor of TARFOX Special Sessions, Spring 1997 Meeting,
American Geophysical Union (AGU). Coordinator, TARFOX special issues of
*Journal of Geophysical Research* (1998-99). Program Co-Chair,
International Specialty Conference on Visual Air Quality, Aerosols, and
the Global Radiation Balance (Bartlett, New Hampshire, 10/1997). Member,
Direct Aerosol Radiative Forcing Committee of IGAC Focus 8: Atmospheric
Aerosols (1996-98).

Previously, Editor (1993, 1996) and Editor-in-Chief (1994-95),
*Geophysical Research Letters*; Member, Board of Editors and Atmospheric
Science Executive Committee, American Geophysical Union. Guest Editor,
*Journal of Geophysical Research* Special Issues on \"Midlatitude
Stratospheric Dynamics and Cross-Tropopause Exchange,\" \"Tropical
Stratosphere-Troposphere Exchange,\" and \"SAGE II Aerosol and Ozone
Data Validation and Initial Data Use\" (1988-93). Convenor, Sessions on
the Atmospheric Effects of 1991 Pinatubo Eruption, AGU Fall Meeting
(1992). Organizer and/or report editor, Workshops on \"Requirements for
a Very-High-Altitude Aircraft for Atmospheric Research,\" \"Scientific
Application of Remotely Piloted Aircraft Measurements of Radiation,
Water Vapor, and Trace Gases to Climate Studies,\" and \"Mission
Measurement Strategies for the Subsonic Assessment Program\" (1989-94).
Member, Interagency Task Group on Airborne Geoscience (1987-89), Member,
American Institute of Aeronautics and Astronautics (AIAA) Losey
Atmospheric Sciences Award Selection Committee, (1986-87), Member, AIAA
Atmospheric Environment Technical Committee (1984-90), Invited
Participant, World Meteorological Organization Experts Meeting on
Aerosols and their Climatic Effects (1983), Invited Participant, NOAA
Workshop on Global Large Aerosols (1982), Chair, American Meteorological
Society International Committee on Laser Atmospheric Studies (1979-82,
Member, 1978-82), Member, National Research Council Committee on Army
Basic Research (1979-81), Member, American Meteorological Society
Committee on Radiation Energy (1979-81).

Previously, Project Scientist, Small High-Altitude Science Aircraft
(SHASA) Project to develop the Perseus A Remotely Piloted Aircraft (RPA,
1992-94), Member, Science/Aeronautics Seam Team of NASA Ames
Reorganization Team (1994), Member, Ad Hoc Committee on the NASA
Environmental Research Aircraft and Sensor Technology (ERAST) Program
(1993-4), Member, NASA Red Team on Remote Sensing and Environmental
Monitoring of Planet Earth (1992-3), Leader, NASA Ames Earth Science
Advanced Aircraft (ESAA) Team (1990-94), Member, National Aero-Space
Plane (NASP) Committee on Natural Environment (1988-94), Member, NASA
Ames Strategy and Tactics Committee (1986-87), Chair, NASA Ames
Atmospheric Science Strategy Review Team (1986-87), Manager, NASA
Stratosphere-Troposphere Exchange Project (STEP, 1983-93), Member, NASA
Solar-Terrestrial Observatory Science Study Group (1979-80), Member,
NASA Atmospheric Lidar Working Group (1977-79) , Member, NASA Spacelab 2
Investigations Review Panel (1977).

NASA Exceptional Service Medal (1988, for managing
Stratosphere-Troposphere Exchange Project), NASA Space Act Award (1989,
for invention of Airborne Autotracking Sunphotometer), and NASA Group
Achievement Awards (1994, for Stratospheric Photochemistry, Aerosols and
Dynamics Expedition; 1991, for Airborne Arctic Stratospheric Expedition;
and 1989, for Airborne Antarctic Ozone Experiment). Graham Prize (1965,
outstanding undergraduate in natural science, Wesleyan University).
Member, Phi Beta Kappa and Sigma Xi.

Patent, \"Airborne Tracking Sunphotometer Apparatus and System\" ( U.S.
Pat. No. 4,710,618, awarded 1987)

**PUBLICATIONS**

(as specified in the Program Announcement, all publications in the past
three years, with up to five other relevant papers)

**2000:**

Collins, D. R., et al. (with P. B. Russell), In situ aerosol size
distributions and clear column radiative closure during ACE-2. *Tellus
B*, in press, 2000.

Durkee, P. A., et al. (with P. B. Russell), Regional aerosol properties
from satellite observation: ACE-1, TARFOX and ACE-2 results. *Tellus B*,
in press, 2000.

Ferrare, R., et al. (with P. B. Russell), Comparisons of aerosol optical
properties and water vapor among ground and airborne lidars and sun
photometers during TARFOX, *J. Geophys. Res*., in press, 2000a.

Ferrare, R., et al. (with P. B. Russell), Comparisons of LASE, aircraft,
and satellite measurements of aerosol optical properties and water vapor
during TARFOX, *J. Geophys. Res*., in press, 2000b.

Gassó, S., et al. (with P. B. Russell), Influence of humidity on the
aerosol scattering coefficient and its effect on the upwelling radiance
during ACE-2. *Tellus B*, in press, 2000.

Hartley, W. S., P. V. Hobbs, J. L. Ross, P. B. Russell and J. M.
Livingston, Properties of aerosols aloft relevant to direct radiative
forcing off the mid-Atlantic coast of the United States, *J. Geophys.
Res.* (2^nd^ Special Issue on TARFOX), in press, 2000.

Ismail, S. , E.V. Browell, R. Ferrare, S. A. Kooi, M. Clayton, V.
Brackett, P.B. Russell, LASE measurement of aerosol and water vapor
profiles measured during TARFOX, *J. Geophys. Res.* (2^nd^ Special Issue
on TARFOX), in press, 2000.

Pilewskie, P., M. Rabette, R. Bergstrom, J. Marquez, B. Schmid, and P.
B. Russell, The discrepancy between measured and modeled downwelling
solar irradiance at the ground: Dependence on water vapor, *Geophys.
Res. Lett,* 27, 137-140, 2000.

Russell, P. B., and J. Heintzenberg, An overview of the ACE-2 Clear Sky
Column Closure Experiment (CLEARCOLUMN), *Tellus B*, in press, 2000.

Welton, E. J., et al. (with P. B. Russell), Ground-based lidar
measurements of aerosols during ACE-2: Instrument description, results,
and comparisons with other ground-based and airborne measurements.
*Tellus B*, in press, 2000.

\[See 2 *Tellus B* papers led by Livingston and Schmid in their CVs.\]

\[See 2 *J. Geophys. Res.* papers led by Redemann in his CV.\]

**1999:**

Bergstrom, R. W., and P. B. Russell, Estimation of aerosol radiative
effects over the mid-latitude North Atlantic region from satellite and
in situ measurements. *Geophys. Res. Lett., 26*, 1731-1734, 1999.

Russell, P. B., P. V. Hobbs, and L. L. Stowe, Aerosol properties and
radiative effects in the United States Mid-Atlantic haze plume: An
overview of the Tropospheric Aerosol Radiative Forcing Observational
Experiment (TARFOX), *J. Geophys. Res*., *104*, 2213-2222, 1999a.

Russell, P. B., J. M. Livingston, P. Hignett, S. Kinne, J. Wong, and P.
V. Hobbs, Aerosol-induced radiative flux changes off the United States
Mid-Atlantic coast: Comparison of values calculated from sunphotometer
and in situ data with those measured by airborne pyranometer, *J.
Geophys. Res.,* 104, 2289-2307, 1999b.

Tanre, D., L. A. Remer, Y. J. Kaufman, S. Mattoo, P. V. Hobbs, J. M.
Livingston, P. B. Russell, and A. Smirnov, Retrieval of aerosol optical
thickness and size distribution over ocean from the MODIS airborne
simulator during TARFOX, *J. Geophys. Res*., *104*, 2261-2278, 1999.

Veefkind, J. P., G. de Leeuw, P. A. Durkee, P. B. Russell, P. V. Hobbs,
and J. M. Livingston, Aerosol optical depth retrieval using ATSR-2 and
AVHRR data during TARFOX, *J. Geophys. Res*., *104*, 2253-2260, 1999.

\[See *Geophys. Res. Lett.* paper led by Schmid in his CV.\]

**1998:**

Boucher, O. et al. (with P. B. Russell), Intercomparison of models
representing direct shortwave radiative forcing by sulfate aerosols, *J.
Geophys. Res., 103*, 16,979-16,998, 1998.

\[6 2-page peer-reviewed extended abstracts in *J. Aerosol. Sci.*
describing TARFOX and ACE-2 results.\]

**1997:**

Hamill, P., E. J. Jensen, P. B. Russell, and J. J. Bauman, \"The Life
Cycle of Stratospheric Aerosol Particles\", *Bull. Am. Meteor. Soc.*,
*78*, 1395-1410, 1997.

Hansen, J., et al. (with P. Russell), "Forcings and Chaos in Interannual
to Decadal Climate Change." *J. Geophys. Res. 102*, 25,679-25,720, 1997.

Hegg, D. A., J. Livingston, P. V. Hobbs, T. Novakov, and P. B. Russell,
\"Chemical Apportionment of Aerosol Column Optical Depth Off the
Mid-Atlantic Coast of the United States,\" *J. Geophys. Res. , 102* ,
25,293-25,303, 1997.

Russell, P. B., S. Kinne and R. Bergstrom, \"Aerosol Climate Effects:
Local Radiative Forcing and Column Closure Experiments,\" *J. Geophys.
Res.,* *102*, 9397-9407, 1997.

**Five Other Relevant Papers:**

Russell, P. B., J. M. Livingston, R. F. Pueschel, J. J. Bauman, J. B.
Pollack, S. L. Brooks, P. Hamill, L. W. Thomason, L. L. Stowe, T.
Deshler, E. G. Dutton, and R. W. Bergstrom. \"Global to Microscale
Evolution of the Pinatubo Volcanic Aerosol, Derived from Diverse
Measurements and Analyses.\" *J. Geophys. Res.*, *101*, 18,745-18,763,
1996a.

Russell, P.B., J. M. Livingston, R. F. Pueschel, J. A. Reagan, E.V.
Browell, G. C. Toon, P.A. Newman, M.R. Schoeberl, L.R. Lait, L. Pfister,
Q. Gao, and B. M. Herman. \"Post-Pinatubo Optical Depth Spectra vs.
Latitude and Vortex Structure: Airborne Tracking Sunphotometer
Measurements in AASE II.\" *Geophys. Res. Lett.*, *20*, 2571-2574, 1993.

Russell, P.B., and M.P. McCormick. \"SAGE II Aerosol Data Validation and
Initial Data Use: An Introduction and Overview.\" *J. Geophys. Res.*,
*94*, 8335-8338, 1989.

Russell, P.B., T.J. Swissler, M.P. McCormick, W.P. Chu, J.M. Livingston,
and T.J. Pepin. \"Satellite and Correlative Measurements of the
Stratospheric Aerosol: I. An Optical Model for Data Conversions.\" *J.
Atmos. Sci.,* *38*, 1270-1294, 1981.

Russell, P.B., J.M. Livingston, and E.E. Uthe. \"Aerosol-Induced Albedo
Change: Measurement and Modeling of an Incident.\" *J. Atmos. Sci.*,
*36,* 1587-1608, 1979.

**(b) Beat Schmid**

**Abbreviated Curriculum Vitae**

### Bay Area Environmental Research Institute

3430 Noriega Street

San Francisco, CA 94122

# Education

  -------------------- --------- ------ -------------------------------------------
  M.S. (Lizentiat)               1991   Institute of Applied Physics, University of
                                        Bern, Switzerland

  Ph.D.                          1995   Institute of Applied Physics, University of
                                        Bern, Switzerland

  Postdoctoral         1995-97          Institute of Applied Physics, University of
  Fellowship                            Bern, Switzerland
  -------------------- --------- ------ -------------------------------------------

# Professional Experience

[Bay Area Environmental Research Institute]{.underline}, San Francisco,
CA (1997-Present)

-Senior Research Scientist

[University of Arizona]{.underline}, Tucson, AZ (Oct. 1995 -Jan. 1996)

-Visiting Scientist

::: Definition-Term
[University of Bern]{.underline}, Switzerland (1989-1997)
:::

-Research Assistant (1989-1995)

-Postdoctoral Researcher (1995-1997)

# Scientific Contributions

-   7 years of leading studies in ground-based and airborne sun
    photometry: instrument design and calibration, development and
    validation of algorithms to retrieve aerosol optical depth and size
    distribution, H~2~O and O~3~.

-   Participate with the NASA Ames Airborne Sun photometers in ACE-2
    (North Atlantic Regional Aerosol Characterization Experiment, 1997,
    Tenerife). Extensive comparison of results (closure studies) with
    other techniques: lidar, optical particle counters, nephelometers,
    and satellites.

-   Participate with the NASA Ames Airborne Sun photometers in the Dep.
    of Energy, Atmospheric Radiation Measurement (ARM) program
    integrated fall 1997 intensive observation period (IOP) in Oklahoma.
    Appointed to lead sun photometer intercomparison. Extensive
    comparison of water vapor results with radiosondes, microwave
    radiometers, lidar, and Global Positioning System.

-   Test of candidate methods for SAGE 3 satellite ozone/aerosol
    separation using airborne sunphotometer data.

-   Application of NOAA/AVHRR satellite data to monitor vegetation
    growth in Switzerland

# Scientific Societies/Committees

-American Geophysical Union

# Publications

(As specified in Program Announcement, all publication in 1997-2000 with
up to five other relevant papers)

**2000:**

**Schmid, B.,** J. M. Livingston, P. B. Russell, P. A. Durkee, H. H.
Jonsson, D. R. Collins, R. C. Flagan, J. H. Seinfeld, S. Gassó, D. A.
Hegg, E. Öström, K. J. Noone, E. J. Welton, K. J. Voss, H. R. Gordon, P.
Formenti, and M. O. Andreae, Clear sky closure studies of lower
tropospheric aerosol and water vapor during ACE-2 using airborne
sunphotometer, airborne in-situ, space-borne, and ground-based
measurements, Tellus, in press, 2000.

Collins, D. R., Jonsson, H. H., Seinfeld, J. H., Flagan, R. C., Gassó,
S., Hegg, D. A., **Schmid, B**., Russell, P. B., Livingston, J. M.,
Öström, E., Noone, K. J., Russell, L. M. and Putaud, J. P. In situ
aerosol size distributions and clear column radiative closure during
ACE-2. Tellus, in press, 2000.

Durkee, P. A., Nielsen, K. E., Smith, P. J., Russell, P. B., **Schmid,
B**., Livingston, J. M., Holben, B. N., Collins, D. R., Flagan, R. C.,
Seinfeld, J. H., Noone, K. J., Öström, E., Gassó, S., Hegg, D., Russell,
L. M., Bates, T. S. and Quinn, P. K. Regional aerosol properties from
satellite observations: ACE-1, TARFOX and ACE-2 results. Tellus, in
press, 2000.

Gassó, S., Hegg, D. A., Noone, K. J., Covert, D. S., **Schmid, B.**,
Russell, P. B., Livingston, J. M., Durkee, P.A. and Jonsson, H. H.
Influence of humidity on the aerosol scattering coefficient and its
effect on the upwelling radiance during ACE2. Tellus, in press, 2000.

Livingston, J. M., V. Kapustin, **B. Schmid**, P. B. Russell, P. K.
Quinn, T. S. Bates, P. A. Durkee, P. J. Smith, V. Freudenthaler, D. S.
Covert, S. Gasso, D. Hegg, D. R. Collins, R. C. Flagan, J. H. Seinfeld,
V. Vitale, and C. Tomasi, Shipboard sunphotometer measurements of
aerosol optical depth spectra and columnar water vapor during ACE-2 and
comparison to selected land, ship, aircraft, and satellite measurements.
Tellus, in press, 2000.

Welton, E. J., Voss, K. J., Gordon, H. R., Maring, H., Smirnov, A.,
Holben, B. N., **Schmid, B.**, Livingston, J. M., Russell, P. B.,
Durkee, P. A., Formenti, P., Andreae, M. O. and Dubovik, O. Ground-based
lidar measurements of aerosols during ACE-2: lidar description, results,
and comparisons with other ground-based and airborne measurements.
Tellus, in press, 2000.

Redemann, J., R.P. Turco, K.N. Liou, P.B. Russell, R.W. Bergstrom, **B.
Schmid**, J.M. Livingston, P.V. Hobbs, W.S. Hartley, S. Ismail, R.A
Ferrare, E.V. Browell. Retrieving the Vertical Structure of the
Effective Aerosol Complex Index of Refraction From a Combination of
Aerosol In Situ and Remote Sensing Measurements During TARFOX. Journal
of Geophysical Research, in press, 2000.

Ferrare, R., S. Ismail, E. Browell, V. Brackett, M. Clayton, S. Kooi, S.
H. Melfi, D. Whiteman, G. Schwemmer, K. Evans, P. Russell, J.
Livingston, **B. Schmid**, B. Holben, L. Remer, A. Smirnov, P. Hobbs.
Comparisons of aerosol optical properties and water vapor among ground
and airborne lidars and sun photometers during TARFOX. Journal of
Geophysical Research, in press, 2000.

Pilewskie, P., M. Rabette, R. Bergstrom, J. Marquez, **B. Schmid**, and
P. B. Russell, The discrepancy between measured and modeled downwelling
solar irradiance at the ground: Dependence on water vapor, *Geophys.
Res. Lett,* 27, 137-140, 2000.

**1999:**

**Schmid B.**, J. Michalsky, R. Halthore, M. Beauharnois, L. Harrison,
J. Livingston, P. Russell, B. Holben, T. Eck, and A. Smirnov, Comparison
of Aerosol Optical Depth from Four Solar Radiometers During the Fall
1997 ARM Intensive Observation Period, *Geophys. Res. Lett.*, Vol. 26,
No. 17, 2725-2728, 1999.

**1998:**

**Schmid, B.**, P.R. Spyak, S.F. Biggar, Ch. Wehrli, J. Sekler, T.
Ingold, C. Mätzler, and N. Kämpfer, "Evaluation of the applicability of
solar and lamp radiometric calibrations of a precision Sun photometer
operating between 300 and 1025 nm." *Applied Optics,* Vol. 37, No. 18,
3923-3941, 1998.

\[5 2-page peer-reviewed extended abstracts describing TARFOX and ACE-2
results in *J. Aerosol Sci.,* Vol. 29, Suppl. 1 and 2.\]

**1997:**

**Schmid, B.**, C. Mätzler, A. Heimo, and N. Kämpfer, Retrieval of
Optical Depth and Size Distribution of Tropospheric and Stratospheric
Aerosols by Means of Sun Photometry. *IEEE Transactions on Geoscience
and Remote Sensing,* Vol. 35, No. 1, 172-182, 1997.

**Two other relevant papers:**

**Schmid, B**., K. J. Thome, P. Demoulin, R. Peter, C. Mätzler, and J.
Sekler, Comparison of Modeled and Empirical Approaches for Retrieving
Columnar Water Vapor from Solar Transmittance Measurements in the 0.94
Micron Region. Journal of Geophysical Research, Vol. 101, No. D5,
9345-9358, 1996.

**Schmid, B**., and C. Wehrli, Comparison of Sun Photometer Calibration
by Langley Technique and Standard Lamp. Applied Optics, Vol. 34, No. 21,
4500-4512, 1995.

**(c) Jens Redemann**

**Abbreviated Curriculum Vitae**

Research Scientist, Bay Area Environmental Research Institute

MS-245, NASA Ames Research Center, Moffett Field, CA 94035-1000

Phone: (650) 604-6259 Fax: (650) 604-3625, email:
<jredemann@mail.arc.nasa.gov>

# PROFESSIONAL EXPERIENCE

  ---------------------------------- ------------------------------------
  Research Scientist                 April 1999 to present

  ---------------------------------- ------------------------------------

> Bay Area Environmental Research Institute, San Francisco.

  ---------------------------------- ------------------------------------
  Research Assistant                 May 1995 to March 1999

  ---------------------------------- ------------------------------------

> **University of California, Los Angeles, Department of Atmospheric
> Sciences.**

  ------------- ---------------------------------------------------------
  Lecturer      Jan. 1999 to March 1999

  ------------- ---------------------------------------------------------

**University of California, Los Angeles, Department of Atmospheric
Sciences.**

  ---------------------------------- ------------------------------------
  Tutor                              1997 to 1998

  ---------------------------------- ------------------------------------

**Ivy West Educational Services, Marina Del Rey, CA.**

  ---------------------------------- ------------------------------------
  Research Assistant                 June 1994 to April 1995

  ---------------------------------- ------------------------------------

Free University of Berlin, Germany. Department of Physics.

# EDUCATION

+----------------------------------+-----------------------------------+
| Ph.D. in Atmospheric Sciences.   | > 1999                            |
+----------------------------------+-----------------------------------+

> University of California, Los Angeles. Specialization: atmospheric
> physics and chemistry.

+----------------------------------+-----------------------------------+
| M.S. in Atmospheric Sciences.    | > 1997                            |
+----------------------------------+-----------------------------------+

> University of California, Los Angeles. Specialization: atmospheric
> physics and chemistry.

+----------------------------------+-----------------------------------+
| M.S. in Physics.                 | > 1995                            |
+----------------------------------+-----------------------------------+

> Free University of Berlin, Germany. Specialization in experimental
> physics and mathematics.

# RELEVANT RESEARCH EXPERIENCE

-   Developed inversion algorithms (C and IDL) and data analysis tools
    for aircraft-based lidar and sunphotometer measurements during field
    experiments (PEM, TARFOX).

-   Compared remotely sensed data to aerosol in situ measurements and
    devised techniques to retrieve the vertical structure of aerosol
    optical properties and radiative effects.

-   Involved in the development of a multi-wavelength, ground-based
    lidar system at the Free University of Berlin, Germany.

-   Provided solutions to scientific and numerical problems pertaining
    to aerosol physics and performed validation measurements relevant to
    Clean Room Technology for the computer chip industry.

-   Specialized course work in atmospheric sciences, geophysical fluid
    dynamics, cloud physics, radiative transfer and remote sensing.

# HONORS

+----------------------------------------------------------+-----------+
| > Invited Speaker at the Atmospheric Chemistry           | ####      |
| > Colloquium for Emerging Senior Scientists (ACCESS V).  | June 1999 |
+----------------------------------------------------------+-----------+
| > Outstanding Student Paper Award, American Geophysical  | > 1998    |
| > Union - fall meeting.                                  |           |
+----------------------------------------------------------+-----------+
| > NASA Global Change Research Fellowship Awards.         | >         |
|                                                          | 1996-1998 |
+----------------------------------------------------------+-----------+
| > UCLA Neiburger Award for excellence in the teaching of | > 1997    |
| > the atmospheric sciences.                              |           |
+----------------------------------------------------------+-----------+

# ORGANIZATIONS

American Association for Aerosol Research, American Geophysical Union,
Co-president of the UCLA - Atmospheric Sciences Graduate Student Group.

# RELEVANT PUBLICATIONS

**2000:**

Redemann, J., R.P. Turco, K.N. Liou, P.B. Russell, R.W. Bergstrom, B.
Schmid, J.M. Livingston, P.V. Hobbs, S. Ismail, E.V. Browell. Retrieving
the Vertical Structure of the Effective Aerosol Complex Index of
Refraction From Aerosol In Situ and Remote Sensing Methods During
TARFOX, *[J. Geophys. Res.]{.underline}*, in press*.*

Redemann, J., R.P. Turco, K.N. Liou, P.B. Russell, R.W.Bergstrom, P.V.
Hobbs, E.V. Browell. Case Studies of the Vertical Structure of the
Aerosol Radiative Forcing During TARFOX, *[J. Geophys.
Res.]{.underline}*, in press*.*

**1999:**

Redemann, J., P.B. Russell, P. Hamill. Measurements and Modeling of
Aerosol Absorption and Single Scattering Albedo at Ambient Relative
Humidity, Presented at the AGU 1999 Fall Meeting, Dec. 13-17, San
Francisco, CA, 1999.

**1998:**

Redemann, J., R.P. Turco, R.F. Pueschel, M.A. Fenn, E.V. Browell and
W.B. Grant. A Multi-Instrument Approach for Characterizing the Vertical
Structure of Aerosol Properties: Case Studies in the Pacific Basin
Troposphere, *[J. Geophys. Res]{.underline}., 103,* 23,287 - 23,298,
1998.

Redemann, J., R.P. Turco, R.F. Pueschel, E.V. Browell, W.B. Grant.
Combining Data From Lidar and In Situ Instruments to Characterize the
Vertical Structure of Aerosol Optical Properties, Presented at the
Nineteenth International Laser Radar Conference, Annapolis, MD, July
6-10, 1998, *[NASA/CP-1998-207671/PT1]{.underline}*, pp.95-99, 1998.

**Before 1997:**

Redemann, J., R.P. Turco, R.F. Pueschel, E.V. Browell, W.B. Grant.
Comparison of Aerosol Measurements by Lidar and In Situ Methods in the
Pacific Basin Troposphere, in '*[Advances in Atmospheric Remote Sensing
with Lida]{.underline}r*', A. Ansmann, R.Neuber, P.Rairoux, U.Wandinger
(eds.), pp.55-58, Springer, Berlin, 1996.

Pueschel, R.F.; D.A. Allen, C. Black, S. Faisant, G.V. Ferry, S.D.
Howard, J.M. Livingston, J. Redemann, C.E. Sorensen, S. Verma, Condensed
Water in Tropical Cyclone "Oliver", 8 February 1993, *[Atmospheric
Research]{.underline}*, 38, pp.297-313, 1995.

**(d) John Livingston**

**Abbreviated Curriculum Vitae**

Senior Research Meteorologist, Applied Physical Sciences Laboratory,

SRI International, Menlo Park, CA 94025

Specialized Professional Competence

Atmospheric physics and meteorology; atmospheric radiometry; computer
simulation of atmospheric remote sensing systems; numerical analysis and
inversion of in-situ and remotely sensed atmospheric data

Representative Research Assignments at SRI (Since 1978)

> Acquisition and analysis of ground-based, airborne, and shipboard
> sunphotometer measurements
>
> Validation of satellite particulate extinction measurements (SAM II,
> SAGE I, and SAGE II), and corresponding studies of the global
> distribution of stratospheric aerosols
>
> Analysis of *in situ* measurements of stratospheric and tropospheric
> aerosols
>
> Acquisition, modeling and analysis of Differential Absorption Lidar
> measurements of tropospheric ozone
>
> Simulation of passive sensor radiance measurements to infer range to
> an absorbing gas
>
> Experimental study of aerosol effects on solar radiation using remote
> sensors
>
> Error analysis and simulation of lidar aerosol measurements
>
> Analysis of lidar propagation through fog, military smoke, and dust
> clouds
>
> Evaluation of the lidar opacity method for enforcement of stationary
> source emission standards
>
> Weather forecasting for large-scale air pollution field study
>
> Testing and evaluation of an offshore coastal dispersion computer
> model
>
> Application of objective wind field and trajectory models to
> meteorological measurements

Professional Experience

> Research Meteorologist to Senior Research Meteorologist, SRI
> International (1978-present)
>
> Research assistant, University of Arizona Institute of Atmospheric
> Physics (1974-1977)
>
> NASA Kennedy Space Center (1975-1976): participant in thunderstorm
> electrification studies

Academic Background

> University of Notre Dame Year-in-Japan Program (1971-1972), Sophia
> University, Tokyo, Japan
>
> B.S. summa cum laude in earth sciences (1974), University of Notre
> Dame, Notre Dame, IN
>
> M.S. in atmospheric sciences (1977), University of Arizona, Tucson, AZ
>
> M.B.A. with highest honors (1992), Santa Clara University, Santa
> Clara, CA

Honors

> NASA Ames Research Center Contractor of the Year (1997), NASA
> Certificate of Recognition (1992) for co-authored technical paper,
> NASA Group Achievement Award (1989) for Airborne Antarctic Ozone
> Experiment

Professional Associations

> American Geophysical Union

**PUBLICATIONS**

**2000:**

Collins, D. R., et al. (with J. M. Livingston), In situ aerosol size
distributions and clear column radiative closure during ACE-2. *Tellus
B*, in press, 2000.

Durkee, P. A., et al. (with J. M. Livingston), Regional aerosol
properties from satellite observation: ACE-1, TARFOX and ACE-2 results.
*Tellus B*, in press, 2000.

Ferrare, R., et al. (with J. M. Livingston), Comparisons of aerosol
optical properties and water vapor among ground and airborne lidars and
sun photometers during TARFOX, *J. Geophys. Res*., in press, 2000a.

Ferrare, R., et al. (with J. M. Livingston), Comparisons of LASE,
aircraft, and satellite measurements of aerosol optical properties and
water vapor during TARFOX, *J. Geophys. Res*., in press, 2000b.

Gassó, S., et al. (with J. M. Livingston), Influence of humidity on the
aerosol scattering coefficient and its effect on the upwelling radiance
during ACE-2. *Tellus B*, in press, 2000.

Hartley, W. S., P. V. Hobbs, J. L. Ross, P. B. Russell and J. M.
Livingston, Properties of aerosols aloft relevant to direct radiative
forcing off the mid-Atlantic coast of the United States, *J. Geophys.
Res.* (2^nd^ Special Issue on TARFOX), in press, 2000.

> Livingston, J. M., V. N. Kapustin, B. Schmid, P. B. Russell, P. K.
> Quinn, T. S. Bates, P. A. Durkee, P. J. Smith, V. Freudenthaler, M.
> Wiegner, D. S. Covert, S. Gassó, D. Hegg, D. R. Collins, R. C. Flagan,
> J. H. Seinfeld, V. Vitale and C. Tomasi, Shipboard sunphotometer
> measurements of aerosol optical depth spectra and columnar water vapor
> during ACE-2 and comparison with selected land, ship, aircraft, and
> satellite measurements. *Tellus B*, in press, 2000.

Redemann, J., et al. (with J. M. Livingston), Retrieving the Vertical
Structure of the Aerosol Complex Index of Refraction From Aerosol In
Situ and Remote Sensing Methods During TARFOX. *J. Geophys. Res*. 2^nd^
TARFOX special issue, in press, 2000.

Schmid, B., et al. (with J. M. Livingston), Clear sky closure studies of
lower tropospheric aerosol and water vapor during ACE-2 using airborne
sunphotometer, airborne in-situ, space-borne, and ground-based
measurements. *Tellus B*, in press, 2000.

Welton, E. J., et al. (with J. M. Livingston), Ground-based lidar
measurements of aerosols during ACE-2: Instrument description, results,
and comparisons with other ground-based and airborne measurements.
*Tellus B*, in press, 2000.

**1999:**

Russell, P. B., J. M. Livingston, P. Hignett, S. Kinne, J. Wong, and P.
V. Hobbs, Aerosol-induced radiative flux changes off the United States
Mid-Atlantic coast: Comparison of values calculated from sunphotometer
and in situ data with those measured by airborne pyranometer, *J.
Geophys. Res.,* 104, 2289-2307, 1999.

Tanre, D., L. A. Remer, Y. J. Kaufman, S. Mattoo, P. V. Hobbs, J. M.
Livingston, P. B. Russell, and A. Smirnov, Retrieval of aerosol optical
thickness and size distribution over ocean from the MODIS airborne
simulator during TARFOX, *J. Geophys. Res*., *104*, 2261-2278, 1999.

Veefkind, J. P., G. de Leeuw, P. A. Durkee, P. B. Russell, P. V. Hobbs,
and J. M. Livingston, Aerosol optical depth retrieval using ATSR-2 and
AVHRR data during TARFOX, *J. Geophys. Res*., *104*, 2253-2260, 1999.

Schmid, B., J. Michalsky, R. Halthore, M. Beauharnois, L. Harrison, J.
Livingston, P.. Russell, B. Holben, T. Eck, and A. Smirnov, Comparison
of aerosol optical depth from four solar radiometers during the Fall
1997 ARM Intensive Observation Period, *Geophys. Res*. *Lett*., *104*,
2261-2278, 1999.

**1998:**

\[6 2-page peer-reviewed extended abstracts in *J. Aerosol. Sci.*
describing TARFOX and ACE-2 results.\]

**1997:**

Hegg, D. A., J. Livingston, P. V. Hobbs, T. Novakov, and P. B. Russell,
Chemical Apportionment of Aerosol Column Optical Depth Off the
Mid-Atlantic Coast of the United States. *J. Geophys. Res. , 102* ,
25,293-25,303, 1997.

**Five Other Relevant Papers:**

Livingston, J.M., and P. B. Russell, Retrieval of aerosol size
distribution moments from multiwavelength particulate extinction
measurements. *J. Geophys. Res.*, *94*, 8425-8433, 1989.

Pueschel, R.F., J. M. Livingston, G. V. Ferry, and T. E. DeFelice,
Aerosol abundances and optical characteristics in the Pacific basin free
troposphere. *Atmos. Envir.*, *28*, 951-960, 1993.

Pueschel, R.F., J. M. Livingston, P. B. Russell, and S. Verma, Physical
and optical prop­erties of the Pinatubo volcanic aerosol: aircraft
observations with impactors and a Sun-tracking photometer. *J. Geophys.
Res.*, *99*, 12,915-12,922, 1994.

Russell, P. B., J. M. Livingston, R. F. Pueschel, J. J. Bauman, J. B.
Pollack, S. L. Brooks, P. Hamill, L. W. Thomason, L. L. Stowe, T.
Deshler, E. G. Dutton, and R. W. Bergstrom, Global to Microscale
Evolution of the Pinatubo Volcanic Aerosol, Derived from Diverse
Measurements and Analyses. *J. Geophys. Res.*, *101*, 18,745-18,763,
1996.

Russell, P.B., J.M. Livingston, and E.E. Uthe, Aerosol-Induced Albedo
Change: Measurement and Modeling of an Incident. *J. Atmos. Sci.*, *36,*
1587-1608, 1979.

**(e) Robert W. Bergstrom**

**Vita**

B.S., Mechanical Engineering, Oregon State University (1968). M.S. and
Ph.D., Mechanical Engineering, Purdue University (1969 and 1972). J.D.,
Law, Stanford University (1983). Member of the California Bar
(1983-present).

Post-Doctoral Fellow, Mainz University, Germany (1972-1973). National
Research Associate, NASA Ames Research Center (1974-1977) . Senior
Scientist, Systems Application Inc., San Rafael CA (1997 -- 1980).
Associate, Law Firm of McCutchen, Doyle, Brown and Enersen, San
Francisco (1983-1984). Assistant Regional Counsel, U.S. EPA, Region IX,
San Francisco, (1984-1992).

Founder of the Bay Area Environmental Research Institute, San Francisco,
CA (1992). Currently, Director of Research.

Guest Investigator on the UARS Satellite Science Team using the
satellite data to explore the effects of the Pinatubo aerosol on
atmospheric radiation. Principal Investigator on several Cooperative
Agreements with NASA Ames Research Center. Currently investigating the
effects of aerosols on atmospheric radiation during ACE-2.

# Publications

**2000:**

Pilewskie, P., M. Rabette, R. Bergstrom, J. Marquez, B. Schmid, and P.
B. Russell, The discrepancy between measured and modeled downwelling
solar irradiance at the ground: Dependence on water vapor, *Geophys.
Res. Lett,* 27, 137-140, 2000.

**1999:**

Bergstrom, R.W. and P.B. Russell, Estimation of aerosol radiative
effects over the mid-latitude North Atlantic region from satellite and
in situ measurements, *Geophys. Res. Lett., 26,* 1731-1734, (1999).

**1998:**

Sokolik, I., O.B. Toon and R.W. Bergstrom, "Modeling the Radiative
Characteristics of Airborne Mineral Aerosols at Infrared Wavelengths,"
*J. Geophys. Res*., *103*, 8813-8826, (1998).

Pilewskie, P. et al. (including R.W. Bergstrom), Observations of the
spectral distribution of solar irradiance at the ground During SUCCESS,"
Geophys. Res. Lett*.*, *25*, 1141-1144, 1998.

**1997:**

Russell, P.B. S. Kinne and R.W. Bergstrom: "Aerosol climate effects:
Local radiative forcing and column closure experiments," *J.
Geophys.Res*, *102*, 9397, (1997)

Kinne, S. et al (including R.W. Bergstrom), \"Cirrus Cloud Radiative and
Microphysical Properties from Ground Observations during FIRE '91,\" *J.
Atmos. Sci., 54*, 2320 (1997).

Seiegnuer, C., et al (including R.W. Bergstrom), "Formulation of a
Second-Generation Reactive Plume and Visibility Model," *J. Air & Waste
Man. Assoc*., *47*, 176 (1997)

**Five Other Relevant Papers:**

Wu, X.H., S. Seignuer and R. W. Bergstrom "Evaluation of a sectional
representation of aerosol size distributions for calculations of optical
properties," *J. Geophys. Res*. *101*, 19277, (1996)

Bergstrom, R.W., B.L. Babson and T.P. Ackerman, \"Calculation of
Multiply Scattered Radiation in Clean Atmospheres,\" *Atmos. Environ*.,
*15*, 1821 (1981).

Bergstrom R.W. and J.T. Peterson, \'Comparison of Observed and Predicted
Solar Radiation in an Urban Area,\" *J. App. Met*., *16*, 1107 (1977).

Bergstrom, R.W. \"Extinction and Absorption Coefficients of Atmospheric
Aerosols as a Function of Particle Size,\" *Beiträge zur Physik der
Atmosphäre*, *46*, 223 (1973).

Bergstrom, R.W. \"Comments on the Estimation of the Absorption
Coefficients of Atmospheric Aerosols,\" *Beiträge zur Physik der
Atmosphäre*, *46*, 198 (1973).

***(*f) Michael A. Box**

**Abbreviated Curriculum Vitae**

B.Sc. (Hons) in Physics, Monash University (Australia), 1969. Ph.D.
Physics, Sydney University (Australia), 1975.

Research Assistant, Melbourne University, 1975-76. Research Scientist,
Institute for Atmospheric Optics and Remote Sensing (NASA Langley
Research Center), 1977-79. Senior Postdoctoral Fellow, Atmospheric
Physics, University of Arizona, 1979-80. Lecturer and Senior Lecturer,
School of Physics, University of New South Wales, 1981-present.
Executive Assistant to Head of School, 1998-2000.

Member, International POLDER Science Working Team. Member, International
Aerosol Radiative Forcing Science Team.

**Publications:**

**2000**

M. J. Kay and M. A. Box, Radiative effects of absorbing aerosols and the
impact of water vapour. *J. Geophys. Res.*, in press.

**1999**

G. Taha and G. P. Box, New method for inferring total ozone and aerosol
optical thickness from multispectral extinction measurements using
eigenvalue analysis. *Geophys. Res. Lett.*, 26, 3085-3088, 1999.

C. Sendra and M. A. Box, Retrieval of the phase function and scattering
optical thickness of aerosols: a radiative perturbation theory
application. *J. Quant. Spect. Rad. Trans.*, 64, 499-525, 1999.

M. A. Box and C. Sendra, Retrieval of the albedo and phase function from
exiting radiances with radiative perturbation theory. *Applied Optics*,
38, 1636-1643, 1999.

C. Sendra and M. A. Box, Information content of the kernel matrix for
the phase function retrieval problem. *Applied Optics*, 38, 1644-1647,
1999.

**1998**

P. E. Loughlin and M. A. Box, Investigating biological response in the
UVB as a function of ozone variability using radiative perturbation
theory. *Photochem. Photobiol,.* B43, 73-85, 1998.

**1997**

M. A. Box, P. E. Loughlin, M. Samaras and T. Trautmann, Applications of
radiative perturbation theory to changes in absorbing gas. *J. Geophys.
Res.,* 102, 4333-4342, 1997.

## Five Other Relevant Papers:

# G. P. Box, M. A. Box and J. Krucker, Information content and wavelength selection in multispectral radiometers. *J. Geophys. Res.,* 101, 19,211-19,214, 1996.

M. A. Box and T. Trautmann, Computation of anthropogenic sulphate
aerosol forcing using radiative perturbation theory. *Tellus*, 46B,
33-39, 1994.

G. P. Box, K. M. Sealey and M. A. Box, Inversion of Mie extinction
measurements using analytic eigenfunction theory. *J. Atmos. Sci.*, 49,
2074-2081, 1992.

G. Viera and M. A. Box, Information content analysis of aerosol remote
sensing experiments using singular function theory. 1: extinction
measurements. *Applied Optics*, 26, 1312-1327, 1987.

M. A. Box, P. Attard, G. Bryant and B. H. J. McKellar, Sum rules for Mie
scattering. *J. Opt. Soc. Am. A*, 4, 795-799, 1987.

**5. CURRENT AND PENDING SUPPORT**

**5.1 Principal Investigator**

+---------------+--------------+---------+-----------+-------+-------+
| **Short       | *            | **      | *         | **    | **Sta |
| Title**       | *Agency/Task | Investi | *Dollar** | Durat | tus** |
|               | No.**        | gator** |           | ion** |       |
|               |              |         | **Value** |       |       |
|               |              | *       |           |       |       |
|               |              | *Months |           |       |       |
|               |              | per     |           |       |       |
|               |              | Year**  |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+
| Improved      | NASA RTOP    | 3       | \$175,000 | 10/98 | F     |
| Exploitation  |              |         | in FY00   | -9/01 | unded |
| of Field Data | 622-44-75-10 |         | (         |       |       |
| Sets in GACP  |              |         | +\$60,000 |       |       |
|               |              |         | for field |       |       |
|               |              |         | ex        |       |       |
|               |              |         | periment) |       |       |
+---------------+--------------+---------+-----------+-------+-------+
| ACE-2 Ship    | NOAA         | 2       | \$99,000  | 4/97  | F     |
| Sunphotometry | Interagency  |         | in FY99   | -3/00 | unded |
| and           | Transfer of  |         |           |       |       |
| Integrated    | Funds        |         |           |       |       |
| Analyses      | NA           |         |           |       |       |
|               | AZ0000700110 |         |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+
| Composite     | NASA RTOP    | 2       | \$57,000  | 10/95 | F     |
| Data Analyses |              |         | in FY00   | -9/00 | unded |
| for Pinatubo  | 621-45-51-10 |         |           |       |       |
| Volcanic      |              |         |           |       |       |
| Aerosols for  |              |         |           |       |       |
| SAGE II       |              |         |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+
| SAGE III      | NASA RTOP    | 2       | \$125,000 | 11/90 | F     |
| Science Team  |              |         | in FY99   | -9/00 | unded |
|               | 229-10-32-00 |         |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+
| Satellite-    | NASA NRA     | 3       | \$225,000 | 2/00  | Requ  |
| Sunphotometer |              |         | in FY00   | -9/02 | ested |
| Studies of    | 99-OES-44    |         |           |       |       |
| Aerosol,      |              |         |           |       |       |
| Water Vapor   |              |         |           |       |       |
| and Ozone     |              |         |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+

**5.2 Co-Investigators\***

+---------------+---------------+----+-------+-------+--------+--------+
| **Short       | **Agency/Task | *  | *     |       |        |        |
| Title**       | No.\***       | *E | *Inve |       |        |        |
|               |               | nd | stiga |       |        |        |
|               |               | Da | tor-M |       |        |        |
|               |               | te | onths |       |        |        |
|               |               | ** | per   |       |        |        |
|               |               |    | Year/ |       |        |        |
|               |               |    | Level |       |        |        |
|               |               |    | of    |       |        |        |
|               |               |    | Eff   |       |        |        |
|               |               |    | ort** |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
|               |               |    | J.    | B.    | J.     | R.     |
|               |               |    | Livin |       |        |        |
|               |               |    | gston | S     | Re     | Ber    |
|               |               |    |       | chmid | demann | gstrom |
+---------------+---------------+----+-------+-------+--------+--------+
| Improved      | NASA RTOP     | 9/ | 2/17% | 3/25% | 6/50%  |        |
| Exploitation  |               | 01 |       |       |        |        |
| of Field Data | 622-44-75-10  |    |       |       |        |        |
| Sets in GACP  |               |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| ACE 2 Ship    | NOAA          | 3/ | 4/33% | 2/17% | 2/17%  | 2/16%  |
| Sunphotometry | Interagency   | 00 |       |       |        |        |
| & Integrated  | Transfer of   |    |       |       |        |        |
| Analyses      | Funds         |    |       |       |        |        |
|               | N             |    |       |       |        |        |
|               | AAZ0000700110 |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| Composite     | NASA RTOP     | 9/ |       |       |        |        |
| Data Analyses |               | 00 |       |       |        |        |
| for Pinatubo  | 621-45-51-10  |    |       |       |        |        |
| Volcanic      |               |    |       |       |        |        |
| Aerosols for  |               |    |       |       |        |        |
| SAGE II       |               |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| SAGE III      | NASA RTOP     | 9/ | 4/33% | 5/42% | 1/8%   |        |
| Science Team  |               | 00 |       |       |        |        |
|               | 229-10-32-00  |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| Satellite-    | NASA NRA      | 9/ | 3.    | 3.    | 5      | 2      |
| Sunphotometer | 99-OES-44     | 02 | 7/31% | 7/31% | .4/45% | .4/20% |
| Studies of    |               |    |       |       |        |        |
| Aerosol,      |               |    |       |       |        |        |
| Water Vapor   |               |    |       |       |        |        |
| and Ozone     |               |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+

\*PI, Award Amount, Period of Performance, Project Title, and Status are
described in preceding Section 5.1.