Proposal GC03-086 to the National Oceanic and Atmospheric Administration

Office of Global Programs

1100 Wayne Avenue, Suite 1210, Silver Spring, MD 20910-5603

Program Element: Aerosol-Climate Interactions Program (ACIP)

Attn: Dr. Joel Levy, 301-427-2089 x111, levy@ogp.noaa.gov

**Quantification of aerosol radiative effects by integrated analyses
of**

**airborne measurements, satellite retrievals, and radiative transfer
models**

Lead Principal Investigator:

Philip B. Russell Date

Research Scientist, Atmospheric Chemistry and Dynamics Branch

Earth Science Division

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

Telephone: 650-604-5404. Fax: 650-604-6779

prussell@mail.arc.nasa.gov

Co-Principal Investigators:

Prong A: Peter Pilewskie, NASA Ames Research Center (Tel. 650-604- 0746,
ppilewskie@mail.arc.nasa.gov)

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

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

Institutional Representative:

David Peterson Date

Acting Chief, Earth Science Division

NASA Ames Research Center

Telephone: 650-604-5899. Fax: 650-604-3625

dpeterson@mail.arc.nasa.gov

Budget requested from NOAA (\$K):

+------------------------+---------+-----------+---------+----------+
| Period                 | [Prong  | [Prong    | [Prong  | Total    |
|                        | A]{.und | B]{.u     | C]{.und |          |
|                        | erline} | nderline} | erline} |          |
|                        | Aerosol | E         | R       |          |
|                        | Abs     | xtinction | egional |          |
|                        | orption | Closure,  | Forcing |          |
|                        | Using   | Including |         |          |
|                        |         | Satellite | Using   |          |
|                        | Flux    | V         | Sa      |          |
|                        | Div     | alidation | tellite |          |
|                        | ergence |           | and     |          |
|                        |         |           | Sub     |          |
|                        |         |           | orbital |          |
+------------------------+---------+-----------+---------+----------+
| March 1, 2003 -        | 99.9    | 100.1     | 95.3    | 295.2    |
| February 28, 2004      |         |           |         |          |
+------------------------+---------+-----------+---------+----------+
| March 1, 2004 -        | 106.4   | 102.8     | 102.0   | 311.2    |
| February 28, 2005      |         |           |         |          |
+------------------------+---------+-----------+---------+----------+
| March 1, 2005 -        | [102.   | [         | [109.   | [32      |
| February 28, 2006      | 3]{.und | 111.9]{.u | 8]{.und | 4.0]{.un |
|                        | erline} | nderline} | erline} | derline} |
+------------------------+---------+-----------+---------+----------+
| Three Year Total       | 308.6   | 314.7     | 309.3   | 932.6    |
+------------------------+---------+-----------+---------+----------+

TABLE OF CONTENTS

LIST OF ACRONYMS ii

ABSTRACT 1

1\. RESULTS FROM PRIOR RESEARCH 2

2.  PROPOSED RESEARCH

(STATEMENT OF WORK) 4

> 2.1 Problem Identification, Overall Objectives, Relevance, and
> Methodology 4
>
> 2.2 Prong A. Aerosol Absorption Using Flux Divergence 6

3.  Prong B. Extinction Closure,

> Including Satellite Validation 10
>
> 2.4 Prong C. Regional Forcing Using Satellite and Suborbital Results
> 14
>
> 2.5. Proposed Tasks and Timetable 16
>
> 2.6. References 17

3\. BUDGET 22

3.  STAFFING, RESPONSIBILITIES,

AND VITAE 25

5\. CURRENT AND PENDING SUPPORT 31

ACRONYMS

  -------------- ------------------ ----------------------------------------------------
  AATS-6 (14)                       6 (14)-channel Ames Airborne Tracking Sunphotometer

  ACE                               Aerosol Characterization Experiment

  ACIP                              Aerosol-Climate Interactions Program

  AERONET                           Aerosol Robotic Network

  AOD                               Aerosol Optical Depth

  ARM                               Atmospheric Radiation Measurement

  ARESE                             ARM Enhanced Shortwave Experiment

  ATSR                              Along Track Scanning Radiometer

  AVHRR                             Advanced Very High Resolution Radiometer

  CCRI                              Climate Change Research Initiative

  CERES                             Clouds and the Earth's Radiant Energy System

  CFORS                             Chemical Weather FORecasting System

  CIRPAS                            Center for Interdisciplinary Remotely Piloted
                                    Aircraft Studies

  CRD                               Cavity Ring-Down

  CRYSTAL-FACE                      Cirrus Regional Study of Tropical Anvils and Cirrus
                                    Layers - Florida Area Cirrus Experiment

  CTM                               Chemical Transport Model

  CW                                Continuous Wave

  CWV                               Column Water Vapor

  DISORT                            DIScrete Ordinates Radiative Transfer

  DOE                               Department of Energy

  EOS                               Earth Observing System

  ESA                               European Space Agency

  GMS                               Geostationary Meteorological Satellite

  GOCART                            Global Ozone Chemistry Aerosol Radiation Transport

  GOES                              Geostationary Operational Environmental Satellite

  INDOEX                            Indian Ocean Experiment

                 IOP                Intensive Observation Period

  JOSS                              Joint Office for Scientific Studies

  MATCH                             Model of Atmospheric Transport and CHemistry

  MISR                              Multi-angle Imaging Spectro-Radiometer

  MODIS                             Moderate-resolution Imaging Spectroradiometer

  NAAPS                             Navy Aerosol Analysis and Prediction System

  NACIP                             National Aerosol-Climate Interactions Program

  NAS                               National Academy of Sciences

  NIR                               Near Infra-Red

  ONR                               Office of Naval Research

  PRIDE                             Puerto RIco Dust Experiment

  SAFARI                            Southern African Regional Science Initiative

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

  SGP                               Southern Great Plains

  SSA                               Single Scattering Albedo

  SSFR                              Solar Spectral Flux Radiometer

  TARFOX                            Tropospheric Aerosol Radiative Forcing Observational
                                    Experiment

  TOMS                              Total Ozone Mapping Spectrometer

  UCAR                              University Corporation for Atmospheric Research
  -------------- ------------------ ----------------------------------------------------

**Quantification of aerosol radiative effects by integrated analyses
of**

**airborne measurements, satellite retrievals, and radiative transfer
models**

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

Co-Principal Investigators:

Peter Pilewskie, NASA Ames Research Center

Beat Schmid, Bay Area Environmental Research Institute

Jens Redemann, Bay Area Environmental Research Institute

Proposed Cost: \$932,600, March 1, 2003-February 28, 2006

**Abstract**. Aerosols are potentially important agents of climate
change, but their impacts on current and future climate are very
uncertain. Three prominent reasons for this uncertainty are: (1) Aerosol
effects on radiative fluxes, clouds and hydrology are critically
dependent on light absorption by aerosols as a function of wavelength
and aerosol type; however, this absorption is currently uncertain,
because aerosols are highly variable, different measurement techniques
often disagree, and some techniques can change the ambient aerosol. (2)
Aerosol effects are equally dependent on the distribution of extinction
(solar beam attenuation) in space, time, and wavelength, but extinction
derived from in situ measurements and other techniques (including
satellite retrievals) often disagrees with measured solar beam
attenuation. (3) Satellites have great potential to reduce uncertainties
in aerosol effects, but limitations or uncertainties in satellite
results require supplementing and/or validating them with other
information.

We propose integrated analyses to address the above three problems in a
coordinated manner. Our objectives are to: (A) Advance the technique of
determining wavelength-dependent aerosol absorption using radiative flux
divergence by comparing flux-divergence results for a variety of
aerosols to results from other techniques and applying the
flux-divergence technique to climatically significant aerosols. (B)
Assess the consistency (closure) between solar beam attenuation measured
by airborne sunphotometer and derived from in situ, lidar, and satellite
methods. (C) Assess regional aerosol radiative forcing by combining
satellite and suborbital inputs in state-of-the-art radiative transfer
models.

We will analyze data sets from field experiments in which vertically
resolved measurements of radiative flux, solar beam attenuation, and
aerosol physical-chemical-optical properties are coordinated with
satellite measurements of Earth-atmosphere reflected radiation. The data
sets are from ACE-Asia (Spring 2001) and the planned DOE SGP Aerosol IOP
(May 2003; see list of acronyms on p. ii). We will attack the above
problems using three highly coordinated prongs, each led by a Co-PI and
focused on one of the above objectives. [Prong A (Aerosol Absorption
Using Flux Divergence)]{.underline} will use measurements by Solar
Spectral Flux Radiometers (SSFRs) to obtain wavelength-dependent aerosol
absorption and will combine absorption with simultaneously measured
optical depths from an Ames Airborne Tracking Sunphotometer (AATS) to
obtain wavelength-dependent single-scattering albedo (SSA). Results from
ACE-Asia and SGP Aerosol IOP data sets will be compared to simultaneous
measurements of absorption and SSA by other techniques. [Prong B
(Extinction Closure]{.underline}) will compare extinction from (i)
AATS-measured solar beam attenuation, (ii) in situ
physical-chemical-optical measurements on the same aircraft, (iii) lidar
and (iv) various satellites. [Prong C (Regional Forcing Assessments by
Combining Satellite and Suborbital Results)]{.underline} will use
advanced satellite data sets and address one of the world's most
climatically significant aerosols---the Asian Pacific plume of mineral
dust, soot, organics, sulfates, and sea salt.

The proposed research will benefit the general public and the scientific
community by reducing the uncertainties about aerosol effects on climate
cited by the National Academy of Sciences (NAS) analysis of key
questions in climate change science and by the White Paper of the
National Aerosol-Climate Interactions

Program (NACIP).

**Quantification of aerosol radiative effects by integrated analyses
of**

**airborne measurements, satellite retrievals, and radiative transfer
models**

**1. RESULTS FROM PRIOR RESEARCH**

As required by the Instructions for Submitting Proposals
(<http://www.ogp.noaa.gov/c&gc>[/ao
/2003/propinstruction.htm]{.underline}), this section summarizes, in two
pages, results of each relevant research project during the last 3
years. More extensive descriptions of selected results and their
relevance to the proposed research are given in Sections 2.2-2.4.

**ACE-2 and ACE-Asia Aerosol Radiative Effect Studies Using Airborne
Sunphotometer, Satellite and In-Situ Measurements.** NOAA Award
NA02AANRG0129, NASA RTOP 622-96-00-57-01, 5/2000-4/2003, \$466,100. This
award supported (a) Acquisition and use of satellite data to plan
ACE-Asia approaches, including selection of areas most favorable to
measuring aerosol radiative effects with least interference by clouds;
(b) Preliminary optical modeling of the complex aerosols expected in
ACE-Asia, by building on models developed for sulfate, carbonaceous, and
mineral dust aerosols studied in TARFOX, ACE-2, and PRIDE; (c)
Comparison of aerosol absorption derived by flux-change and other
techniques in TARFOX and ACE-2; (d) Contributions to the Science and
Implementation Plan for ACE-Asia 2001; (e) Development and testing of
sunphotometric water vapor analysis techniques for ACE-Asia; (f) Mission
Scientist duties for ACE-Asia C-130 flights addressing aerosol-radiation
interactions; (g) Calibrations, integration, test flights, and
measurements using the 6-channel Ames Airborne Tracking Sunphotometer
(AATS-6) on the C-130 in ACE-Asia Spring 2001; (h) Intercomparisons,
validations, and closure analyses combining the AATS-6 data with
satellite and other suborbital data; and (i) Aerosol radiative effect
calculations that combine satellite and suborbital inputs. Results are
described in four journal publications led by our team (Redemann et al.,
2001a; Bergstrom et al., 2002a; Russell et al., 2002; Schmid et al.,
2001), plus several others we coauthored (e.g., Ingold et al., 2000;
Kiedron et al., 2000; Revercomb et al., 2001; Wang et al., 2002a). Our
AATS-6 ACE-Asia data set has been archived and made available to the
user community via the Ames web site
(<http://geo.arc.nasa.gov/sgg/AATS-website/AATS_Data.html>) and a link
from UCAR-JOSS. These data are being used in many ongoing studies that
have been reported at numerous conferences (e.g., Chin et al., 2001;
Livingston et al., 2001; Redemann et al., 2001b,c; Russell et al.,
2001a,b; Kuzmanoski et al., 2002). Selected results are summarized in
Sections 2.2-2.4 of this proposal.

**Solar Spectral Flux, Optical Depth, Water Vapor, and Ozone
Measurements and Analyses in the ACE-Asia Spring 2001 Intensive
Experiment.** Office of Naval Research Award N0001401F0183, NASA RTOP
622-96-00-56-79, 11/2000-9/2002, \$163,900. This award supported
measurements and analyses of solar spectral fluxes and direct beam
transmissions in support of the ACE-Asia Spring 2001 Intensive
Experiment. Spectral fluxes (300-1700 nm at 10 nm resolution) were
measured by zenith and nadir viewing Solar Spectral Flux Radiometers
(SSFRs) on the CIRPAS Twin Otter. Simultaneously and on the same
aircraft, direct beam transmissions were measured in 14 narrow bands
(354-1558 nm) by AATS-14. The AATS-measured beam transmissions were
analyzed to derive aerosol and thin-cloud optical depth at 13
wavelengths, plus column water vapor overburden. The data were used to
support the overall goals of ACE-Asia, with emphasis on determining the
net solar radiative forcing of East Asian/West Pacific aerosols,
quantifying the solar spectral radiative energy budget in the presence
of elevated aerosol loading, supporting satellite algorithm validation,
and providing tests of closure with in situ measurements. Our AATS-14
ACE-Asia data set has been archived and made available to the user
community (see above for link). Results are described in Wang et al.
(2002a), in numerous ACE-Asia conference presentations, and in many
papers being drafted for the ACE-Asia special issue of *J. Geophys.
Res*. Selected results are shown in Sections 2.2-2.4.

**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, 10/98-9/02, \$675,000. This award
supported 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. These tasks were
accomplished primarily by analyses of data sets from TARFOX and ACE-2.
Results are described in 10 journal publications led by the Ames
sunphotometer-satellite team (Bergstrom and Russell, 1999; Bergstrom et
al., 2002a; Livingston et al., 2000; Redemann et al., 2000a,b, 2001;
Russell and Heintzenberg, 2000; Russell et al., 2002; Schmid et al.,
1999, 2000), plus 9 others we coauthored (Collins et al., 2000; Ferrare
et al., 2000a,b; Flamant et al., 2000; Gasso et al., 2000; Hartley et
al., 2000; Ismail et al., 2000; Pilewskie et al., 2000; Welton et al.,
2000).

**Satellite-Sunphotometer Studies of Aerosol, Water Vapor, and Ozone
Roles in Climate-Chemistry-Biosphere Interactions.** NASA RTOP
291-01-91-45, 2/1999-12/2002, \$675,000. This award supported modeling
and integrated analyses of suborbital and satellite data to address
impacts of biomass smokes, Asian and African soil dust, and other
tropospheric aerosols and water vapor on the Earth's radiation budget.
Research focused primarily on analysis of data from three international
multiplatform field campaigns: PRIDE, SAFARI 2000, and ACE Asia. Data
from airborne sunphotometers and other airborne and surface remote and
in situ measurements were combined in closure studies to test and
improve models of complex multicomponent tropospheric aerosols and their
interactions with water vapor and radiation. Pre-campaign modeling and
algorithm development focused on providing realtime analysis and display
capabilities useful for studies of aerosol evolution and mass budgets,
including flight planning and direction. During and after campaigns
suborbital data and models were used to validate satellite measurements
of aerosols and water vapor. They were then used to supplement the
satellite data with other information needed for studies of aerosol
physicochemical evolution and radiative-climatic effects. In particular,
satellite maps of aerosol properties were combined with suborbital data
in radiative transfer models to assess aerosol effects on radiation
balance and heating rates, both at the surface and aloft. Thirteen
journal manuscripts were submitted, describing results from PRIDE,
SAFARI 2000, and ACE Asia (Bergstrom et al., 2002b; Colarco et al.,
2002; Gatebe et al., 2002; Levy et al., 2002; Livingston et al., 2002;
Magi et al., 2002; McGill et al., 2002; Pilewskie et al., 2002a; Reid et
al., 2002; Schmid et al., 2002; Wang et al., 2002a,b; Xu et al., 2002).

**Investigation of the Uncertainty and Variability of the Direct
Spectral Radiative Forcing by Atmospheric Aerosols.** NASA RTOP
622-44-76-10, 10/1998-9/2002, \$348,000. This award supported the
analysis of hyperspectral solar flux measurements from various flight
missions to determine the direct radiative forcing by aerosols. Three
journal manuscripts were submitted, describing results from PRIDE and
SAFARI 2000 (Bergstrom et al., 2002b; Pilewskie et al., 2002a,c).
Selected results are summarized in Section 2.2.

**Retrieval of Ice-Water Content Using Near-Infrared Remote Sensing.**
DOE Atmospheric Radiation Measurement Program, Solicitation Notice
99-16, NASA RTOP 622-43-00-56-33, 10/1999-9/2002, \$230,000. This award
supported the use Solar Spectral Flux Radiometer (SSFR) data to infer
cloud water (ice or liquid) path and effective water content. Results
recently submitted for publication (Pilewskie et al., 2002b) show that
SSFR flux spectra measured above and below cloud can be used to derive
cloud optical and physical properties which are in agreement with in
situ microphysical measurements. See also Section 2.2.4.

**Measurement of Solar Spectral Irradiance in Support of CRYSTAL.** NASA
RTOP 622-44-76-10, 10/2001-9/2002, \$437,000. This award supported
measurements by Solar Spectral Flux Radiometers (SSFRs) and broadband
infrared radiometers on two aircraft (ER-2 and Twin Otter) in the Cirrus
Regional Study of Tropical Anvils and Cirrus Layers - Florida Area
Cirrus Experiment (CRYSTAL-FACE, July 2002), including sensor
preparation, modification, calibration, integration, flight operation,
and initial data reduction. Complete data analysis, presentation, and
publication are planned for FY 2003-2004.

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

**2.1 Problem Identification, Overall Objectives, Relevance, and
Methodology**

Aerosol effects on atmospheric radiation pose major uncertainties in
understanding past and present climates and in predicting the future
climate. These uncertainties, and strategies for reducing them, have
recently been emphasized by the National Academy of Sciences' analysis
of key questions in climate change science (NAS, 2001). Recent
experiments designed to reduce these uncertainties (e.g., TARFOX, ACE-2,
INDOEX, PRIDE, SAFARI-2000, ACE-Asia) have produced important advances
but in the process have posed remaining questions that must be answered
(Russell et al., 1999a; Raes et al., 2000; Russell and Heintzenberg,
2000; Ramanathan et al., 2001, 2002; Levy, 2002c). These remaining
questions have guided the research priorities and strategies articulated
by the National Aerosol-Climate Interaction Program (NACIP) and in turn
by NOAA's Aerosol-Climate Interactions Program (ACIP). For example,
NACIP and ACIP (Ramanathan et al., 2002; Levy, 2002a,b) emphasize the
importance of absorbing aerosol components (including black and organic
carbon and mineral dust) both in directly affecting Earth-atmosphere
radiation budgets and in determining aerosol-cloud interactions and
regional hydrology. Aerosol absorption deposits solar energy that would
have warmed Earth's surface into atmospheric layers aloft. There it can
shorten cloud lifetimes by causing them to "burn off" (Ackerman et al.,
2000). Absorbing aerosols can also inhibit cloud formation in several
ways. The reduction in surface heating decreases evapotranspiration, and
the combination of increased heating aloft and reduced heating below
weakens the convective motions that drive much cloud formation. Thus
aerosol absorption can affect regional hydrology in addition to
radiative forcing. Quantifying these effects requires a quantitative
description of the vertical, regional, and temporal distributions of
aerosol absorption across all wavelengths where absorbed energy is
significant.

In its White Paper (Ramanathan et al., 2002) NACIP also emphasizes the
need to quantify aerosol properties and effects on a region-by-region
basis and to represent these properties and effects accurately in models
that calculate aerosol radiative and climatic effects. The "new
paradigm" of NACIP is to attack the aerosol-climate forcing problem from
an observational basis. NACIP stresses that a sound observational basis
requires combining satellite observations (the only mode for global
observations of aerosols) with multi-platform measurements at the
surface and within the atmosphere, including aircraft flights to map the
vertical and horizontal variations of key aerosol properties and
effects. NACIP also stresses the need to both quantify and reduce the
uncertainties in both observations and model calculations.

The current NOAA ACIP call for proposals (Levy, 2002a) has focused the
above NACIP priorities into three specific areas in which proposals are
solicited. These areas include:

1\. Investigations that address limiting factors in current in-situ
measurement capabilities by using methods or instruments capable of
autonomous operation on light aircraft. Prime examples are methods to
measure aerosol light absorption and intercomparisons of different
instruments.

2\. Spin-up of comprehensive light aircraft field measurements of the
most radiatively important aerosols, highly integrated with
state-of-the-art modeling.

3\. Analyses of ACE-Asia data that stress synergistic use of
multi-disciplinary data sets, with emphasis on achieving closure on the
radiative impacts of Asian aerosols observed during the campaign.

This proposal addresses all three of the above ACIP-solicited areas in a
coordinated fashion. The objectives of the proposed research are:

A.  Advance the technique of determining wavelength-dependent aerosol
    absorption using radiative flux divergence by comparing
    flux-divergence results for a variety of aerosols to results from
    other techniques and applying the flux-divergence technique to
    climatically significant aerosols.

B.  Assess the consistency (closure) between solar beam attenuation
    measured by airborne sunphotometer and derived from in situ, lidar,
    and satellite methods.

C.  Assess regional aerosol radiative forcing by combining satellite and
    suborbital inputs in state-of-the-art radiative transfer models.

Our proposed approach is to analyze data sets from field experiments in
which vertically and horizontally resolved measurements of radiative
flux, solar beam attenuation, and aerosol physical-chemical-optical
properties are coordinated with satellite measurements of
Earth-atmosphere reflected radiation. The data sets, from ACE-Asia
(Spring 2001) and the planned DOE SGP Aerosol IOP (May 2003) are
described more fully below. First we describe how the work would be
organized and the methods employed.

We plan to attack the above problems using three highly coordinated
prongs, each led by a Co-PI (as listed on the cover page) and focused on
one of the above objectives.

[Prong A. Aerosol Absorption Using Flux Divergence]{.underline}.
Radiative flux is the flow of radiant energy (diffuse plus direct)
across a surface. The net (downwelling minus upwelling) flux at the top
of a layer minus the net flux at the bottom (i.e., the net flux
divergence across a layer) is the energy absorbed by the layer. Hence,
flux divergence measurements are a direct way of determining the
absorption by whatever is in an atmospheric layer, in its ambient state.
Measuring flux divergence with fine spectral resolution allows the
identification and subtraction of gas absorption features, thus
isolating the aerosol absorption. Perturbation or loss of aerosol
particles by aircraft and instrument inlet and filter effects is
avoided. As shown in Section 2.2, early publications from PRIDE and
SAFARI illustrate how Dr. Pilewskie's Solar Spectral Flux Radiometers
(SSFRs) yield wavelength-dependent aerosol absorption, which, when
combined with optical depths from an Ames Airborne Tracking
Sunphotometer (AATS) in a radiative transfer model, yields
wavelength-dependent single-scattering albedo (SSA). These techniques
will be applied to the ACE-Asia and SGP Aerosol IOP data sets, and the
results compared to simultaneous measurements of absorption and SSA by
other techniques.

[Prong B. Extinction Closure, Including Satellite
Validation]{.underline}. An important class of extinction closure
studies addresses the question: \"Can in situ measurements of aerosol
properties account for the solar beam attenuation (extinction) by an
aerosol layer or column?\" Measuring solar beam attenuation by an AATS
on the same aircraft as in situ sensors allows an exact match in the
aerosol layers described by the attenuation and in situ measurements.
Such a match allows the best-defined comparison between attenuation and
in situ results. As shown in Section 2.3, such comparisons have revealed
important insights about aerosol sampling and inadvertent modification
in such previous experiments as TARFOX, ACE-2, and SAFARI. We will base
the proposed study of extinction closure on the ACE-Asia and SGP Aerosol
IOP data sets. In addition to comparisons to airborne in situ
measurements we will include comparisons to lidar extinction profiles
and total column aerosol optical depth (AOD) from various satellites and
models (see Section 2.3).

[Prong C. Regional Forcing Assessments by Combining Satellite and
Suborbital Results]{.underline}. As amplified in Section 2.4, this prong
will use the general approach we applied to North Atlantic aerosols
(Bergstrom and Russell, 1999), but will extend it in many ways: by using
more advanced satellite and suborbital data sets and by applying it to
the Asian-Pacific aerosol. This aerosol is one of the world's most
climatically significant because of its great concentration, extent, and
expected growth (e.g., Huebert et al., 1999). It is also one of the most
difficult to assess, because it is a complicated and varying mixture of
many components, including desert dust, a strong soot component,
organics, sulfates, and sea salt.

As noted above, these methods will be applied to the following data
sets:

[Data Set 1. ACE-Asia (Spring 2001)]{.underline}. This set includes
measurements on the Twin Otter aircraft by SSFRs, AATS-14, and many in
situ sensors, plus measurements on the C-130 aircraft by AATS-6 and many
other sensors, all made in coordination with satellite overpasses. The
satellite data products include multiwavelength aerosol optical depth
(AOD) from sensors such as MISR, MODIS, SeaWiFS, AVHRR, and others. Also
useful in the analyses will be the fields of AOD and other properties
predicted by the chemical-transport models (CTMs) CFORS, GOCART, MATCH,
and NAAPS (see list of acronyms on p. iii; see Section 2.3 for
references describing models). The ACE-Asia campaign ended about 1 year
ago, and early presentations (e.g., Redemann et al., 2001b,c) and
journal manuscripts (e.g., Wang et al., 2002a) have demonstrated the
outstanding quality and scope of the data set. However, our current
ACE-Asia analysis funding will end within a year and will not cover the
highly integrated analyses proposed here. The ACE-Asia data set provides
a golden opportunity to extend the abovementioned PRIDE and SAFARI flux
divergence analyses to one of the world's most climatically significant
aerosols---the Asian Pacific plume of desert dust and pollution.

In addition to the satellite sensors mentioned above, we plan to
contribute to the validation of CERES data by furnishing ACE-Asia AATS-6
and -14 data, and data-use advice, to Dr. Sundar Christopher of the
University of Alabama in Huntsville. Dr. Christopher is proposing to
NOAA ACIP an investigation that would, among other things, use biaxial
scan mode CERES data to develop angular models for estimating radiative
fluxes and thereby reduce uncertainties in aerosol radiative forcing.

[Data Set 2. DOE SGP Aerosol IOP (May 2003).]{.underline} Plans for this
experiment, which recently received tentative approval from the ARM
Science Team Executive Committee, include measurements by SSFR, AATS-14,
and many others. A significant advance will be mounting the up-looking
SSFR on a stable platform, which will reduce tilt effects and thereby
extend the SSFR absorption analyses to smaller aerosol optical depths.
This will extend the range of aerosol conditions to which the flux
divergence technique can be applied. Dr. Beat Schmid (Co-PI) has been
involved in the planning of the May 2003 IOP and has developed an
airborne payload based on the CIRPAS Twin Otter aircraft.

**2.2 Prong A. Aerosol Absorption Using Flux Divergence**

The goals of this prong of the proposed research are to:

• Advance the technique of determining wavelength-dependent aerosol
absorption using radiative flux divergence, by comparing flux-divergence
results for a variety of aerosols to results from other techniques and
applying the flux-divergence technique to climatically significant
aerosols.

• Provide results on wavelength-dependent absorption and SSA of
significant aerosol types to Prongs B and C and to the community via
summary data files, presentations and publications.

Several recent airborne intensive field campaigns conducted to study the
radiative forcing of clouds and various types of aerosols have included
the measurement of solar spectral irradiance over flight profiles
throughout the troposphere and lower stratosphere. These data provided
the means to determine the net spectral flux at various atmospheric
levels, from which spectral flux divergence and absorption were derived.
Further analysis through radiative transfer modeling has been applied to
derive aerosol or cloud droplet single scattering albedo. The initial
successes of these measurements and analyses provide the basis for
expanding our efforts toward the objectives described in this proposal.
In this section we describe the measurement and modeling tools used and
present some of our results from recent field studies.

**2.2.1 The Solar Spectral Flux Radiometer**

The Solar Spectral Flux Radiometer (SSFR) is a moderate resolution flux
(irradiance) spectrometer covering the wavelength range 300-1700 nm. The
SSFR uses an identical pair of Zeiss Monolithic Miniature Spectrometer
Modules (MMS-1 and MMS-NIR) for simultaneous zenith and nadir viewing.
The MMS-1 has a flat-field, 366 mm^-1^ grating and a Hamamatsu Si linear
diode array detector. We control the MMS-1 module temperature to 27±0.3º
C. The MMS-NIR has a 179 mm^-1^ flat-field grating with a 128-element
InGaAs linear diode array, thermoelectrically cooled to 0º C. Spectral
resolution is 9 nm for the MMS-1 and 12 nm for the MMS-NIR. The light
collector is a scaled version of the optical collector designed by
Crowther (1998). Tests of the design show a high degree of linearity
with cosine of incidence angle to values as low as 0.1. A water-free
quartz hyperdome protects the light collector in flight. A high-grade
custom-made fiber optic bundle transmits incident light to the two
spectrometer input slits. Data acquisition and control use a 226 MHz 586
PC. Dynamic resolution is 15 bits full range; sampling resolution is
\~3.25 nm. Spectral sampling is at \~1 Hz. Data is recorded on a 220
Mbyte PCMCIA flash memory card.

The SSFR is calibrated for wavelength, angular response, and absolute
spectral power. Spectral calibration is referenced to the HeNe laser
line at 632.8 nm, a temperature stabilized laser diode line at 1298 nm,
and several lines from Hg, Xe, and Ar lamps. Spectral power calibration
uses a NIST secondary standard lamp and a LI-COR Field Calibrator. The
LI-COR units are fully enclosed devices suitable for field use. In the
field we calibrate the SSFR before and after flights using the same
portable LI-COR devices to monitor SSFR stability during the experiment.

Over most of the active spectral range the short-term stability, or
precision, is \<0.1% for the Si detector array and \<0.2% for the InGaAs
array. The longer term stability shown by pre- and post-deployment
comparisons is \~0.5% (\~0.75%) for the Si (InGaAs) array, with some
falloff at the detection limits. Absolute accuracy of SSFR irradiance
spectra depends mostly on the accuracy of the transfer standard. The
error over our spectral range for the NIST standard used to calibrate
the SSFR was 1-3%. The LI-COR calibrator lists a 3% uncertainty across
the spectrum. Aircraft pitch and roll contribute additional error during
aircraft operations. Later in this section we quantify this error in
terms of error bars on derived aerosol absorption and SSA, showing that
the error was acceptable for aerosol optical depths commonly observed in
SAFARI, PRIDE, and ACE-Asia. As noted above (see [Data Set
2]{.underline}), pitch and roll effects will be reduced in the planned
DOE SGP Aerosol IOP by mounting the up-looking SSFR on a stable
platform, thus extending the range of aerosol conditions to which the
flux divergence technique can be applied

## 

## 2.2.2 Radiative Transfer Model

We have developed a numerical radiative transfer model specifically for
comparison with the SSFR. Major features of the model are: a
k-distribution representation for O~2~, O~3~, CO~2~ and H~2~O absorption
coefficients (Mlawer, et al, 1997); DISORT, a multiple scattering code
(Stamnes, et al, 1988); Kurucz representation of the solar spectrum
(Kurucz, 1992); and SSFR filter functions (Pilewskie et al, 2002). The
140 model bands (10 nm wide, 300-1700 nm) match the SSFR spectral
coverage. Model inputs are vertical profiles of gases, aerosol and
clouds, spectral scattering and absorption properties of aerosols and
clouds, spectral surface reflectance, and solar zenith angle. Bergstrom
et al. (2002b) describe the details of the code and present comparisons
with measured spectral irradiance from biomass-burning aerosol layers,
plus solutions for wavelength-dependent SSA of aerosol layers.

**2.2.3 Flux Divergence in Aerosol Layers**

The net flux at any level is defined as the difference between
downwelling and upwelling irradiance:

F~net~ = F~↓~ - F~↑ ~.

The flux divergence, or absorption, A, in a layer is defined as the
difference between net flux above and below a layer:

A = (F~↓~ - F~↑~)~2~−(F~↓~ - F~↑~)~1 ~,

where 2 and 1 denote upper and lower flight levels, respectively.
Finally, we determine fractional absorption, α, by normalizing the layer
absorption by the downwelling flux incident at the top of the layer:

α = [(F~↓~ - F~↑~)~2~−(F~↓~ - F~↑~)~1~]{.underline}

> F~↓2~

**2.2.3.1 Biomass Burning Aerosol.** The SSFRs flew on the University of
Washington Convair-580 during the Southern African Regional Science
Initiative (SAFARI 2000), affording the opportunity to apply the flux
divergence technique to the biomass burning aerosols that prevailed in
that study. Figure 1 shows results from the 6 September flight, which
included two stacked level legs over Mongu, Zambia, during an intense
haze episode. SSFR downwelling and upwelling irradiance (flux) spectra
are shown in Figure 1a; albedo spectra (ratios of upwelling to
downwelling flux) are in Figure 1b, and aerosol optical depths measured
simultaneously by AATS-14 from the same aircraft are in Figure 1c. Note
that the near-infrared albedo aloft (575 mb) is less than that near the
surface (878 mb), suggesting very strong absolute absorption by the
massive optically thick haze layer present between these two heights.
Figure 2a shows the spectral absorption for this layer. The solid curve
is total absorption; by interpolating across the various near-infrared
gas absorption bands we estimate the aerosol contribution to the
absorption as depicted by the dashed curve.

![](media/image1.pct){width="3.1993055555555556in"
height="3.9090277777777778in"}

**Figure 1.** (a) Upwelling and downwelling flux spectra from two SAFARI
Convair-580 flight legs on 6 September 2000. (b) Albedo spectra from the
same legs. (c) Corresponding aerosol optical depths from AATS-14
measurements.

![](media/image2.pct){width="3.497916666666667in" height="3.1875in"}

**Figure 2.** (a) Spectral flux divergence (absorption) between the
highest and lowest flight legs in the 6 September flight profile over
Mongu, Zambia. The dashed curve represents the aerosol absorption
"continuum." (b) Fractional absorption from the same case. Red curves
indicate the range of uncertainty.

![](media/image3.pct){width="3.5770833333333334in" height="3.49375in"}

**Figure 3**. Derived single scattering albedo for the biomass burning
aerosol sampled in the 6 September 2000 Mongu, Zambia, case study.

![](media/image4.pct){width="3.1791666666666667in"
height="2.567361111111111in"}

**Figure 4**. Measured (blue spectrum) and modeled (red triangles)
fractional absorption for a dust layer during the PRIDE case study on 15
July 2000.

![](media/image5.pct){width="3.1902777777777778in"
height="2.5069444444444446in"}

**Figure 5**. (a) Measured (blue) and modeled (red) absorption spectra
for the ACE-Asia profile flown on Twin Otter Flight RF07, 12 April 2001.
(b) Corresponding spectra of fractional absorption. (c) AOD spectra
measured simultaneously on the same aircraft.

The fractional absorption in Figure 2a can be combined with the AOD in
Figure 1c to estimate aerosol single scattering albedo using the
radiative transfer model described above. The best-fit single scattering
albedo thus obtained is shown in Figure 3 with the wavelength regions
dominated by gaseous absorption removed. The error bars for the single
scattering albedo are estimated from the error bars in the fractional
absorption, shown in Figure 2b. These errors result primarily from
uncertainties in SSFR tilt during aircraft pitch and roll (see also
below). The spectral slope of the aerosol SSA shows the decrease with
wavelength expected for black carbon (Bergstrom et al., 2002a).

**2.2.3.2 Dust Aerosol.** Radiative profiles in dust layers were
acquired during the Puerto Rico Dust Experiment (PRIDE) and the Asian
Pacific Aerosol Characterization Experiment (ACE-Asia). Following the
methodology described above, we used these to derive the spectral
absorption in dust layers from which aerosol radiative parameters could
be derived. Figure 4 shows agreement between measured and modeled dust
absorption during PRIDE on 15 July 2000.

Figure 5 shows spectra of absorption and AOD measured simultaneously on
an ACE-Asia flight. The model calculations shown in Figure 5 assumed a
wavelength-independent SSA, which clearly underestimates absorption for
wavelengths \<600 nm. Adjusting model SSA to produce a match between
modeled and measured absorption yields the SSA values shown in Figure 6.
Figure 7 compares the SSA spectra derived for these PRIDE and ACE-Asia
cases to published results for

![](media/image6.pct){width="3.120833333333333in"
height="2.6527777777777777in"}

**Figure 6**. Aerosol single scattering albedo spectra derived from the
measured flux and AOD spectra in Figure 5.

![](media/image7.pct){width="3.2979166666666666in"
height="2.5215277777777776in"}

**Figure 7**. Derived dust single scattering albedo from PRIDE (blue
curve) and ACE-Asia (green curve). Five aerosol models are shown for
comparison (Quijano et al., 2000; Ackerman and Cox, 1988)

Saharan, Afghan and SW Asian dusts (Quijano et al., 2000; Ackerman and
Cox, 1988).

**2.2.4 Solar Absorption in Clouds, and Relationship to Aerosols**

The NACIP White Paper (Ramanathan et al., 2002) emphasizes the need to
elucidate the many aerosol-cloud interactions. As noted in Section 2.1,
one such interaction is the "burning off" of clouds by aerosol
absorption, and there are others relating to modified surface
evapotranspiration and atmospheric dynamics. Hence, there is a need to
better understand the relationships between aerosol absorption and cloud
properties. In this connection we note that the flux divergence method
can be used to measure cloud absorption and other properties as well as
aerosol absorption. In fact, SSFR measurements have been used for this
purpose in the second ARM Enhanced Shortwave Experiment (ARESE II).
Recent results (Pilewskie et al., 2002b) show that SSFR flux spectra
measured above and below cloud can be used to derive cloud absorption,
mean effective droplet radius, cloud optical depth, and cloud water path
values that agree with in situ microphysical measurements within the
range of instrumental uncertainty. In the proposed research we plan to
explore this capability by selecting and analyzing appropriate
cloud-aerosol cases in the ACE-Asia and SGP Aerosol IOP data sets.

**2.3 Prong B. Extinction Closure, Including Satellite Validation**

The goals of this prong of the proposed research are to:

• Assess the consistency (closure) between solar beam attenuation
measured by airborne sunphotometer and derived from in situ, lidar, and
satellite methods.

• Provide results, grouped by aerosol condition, to Prongs A and C and
to the community via summary data files, presentations and publications.

An important class of extinction closure studies addresses the question:
\"Can in situ measurements of aerosol properties account for the solar
beam attenuation (extinction) by an aerosol layer or column?\" Such
closure studies have revealed important insights about aerosol sampling
and inadvertent modification in such previous experiments as TARFOX
(Hegg et al., 1997; Hartley et al. 2000), ACE-2 (Collins et al., 2000,
Schmid et al., 2000) and SAFARI 2000 (Magi et al., 2002). We will base
the study of extinction closure on the ACE-Asia and SGP Aerosol IOP data
sets, and will include lidar extinction profiles and total column AOD
from various satellites (as done for SAFARI by Schmid et al., 2002) and
models (see below).

Key is the measurement of aerosol optical depth and columnar water vapor
with the Ames Airborne Tracking Sunphotometers, AATS-14 and AATS-6
(e.g., Matsumoto et al., 1987). This is because inlet effects (e.g.,
loss or enhancement of large particles, shrinkage by evaporation of
water, organics, or nitrates) and filter effects are avoided. AATS-14
measured the transmission of the direct solar beam at 14

![](media/image8.pct){width="4.831944444444445in"
height="3.6256944444444446in"}

**Figure 8.** Left panel: Aerosol optical depth profiles at 13
wavelengths from 354 to 1558 nm calculated from AATS-14 measurements
acquired during an aircraft ascent south of Korea on 17 April 2001
during ACE-Asia. Right panel: Corresponding aerosol extinction profiles
derived by differentiating spline fits (dashed lines in left panel) to
the optical depth profiles.

discrete wavelengths λ, from 354 to 1558 nm, during ACE-Asia. For the
SGP Aerosol IOP the instrument's wavelength range is currently being
extended to 2138 nm. AATS-6 measures at 6 discrete wavelengths between
380 and 1020 nm. From the direct solar beam transmission measurement we
derive spectral aerosol optical depths AOD(λ), columnar water vapor,
CWV, and columnar ozone. Flying at different altitudes over a fixed
location allows derivation of AOD(λ) or CWV in a given layer. Data
obtained in vertical profiles allows derivation of spectral aerosol
extinction *E~a~*(λ) (see ) and water vapor density *ρ*~w~.

Measuring solar beam attenuation by an AATS on the same aircraft as in
situ sensors allows an exact match in the aerosol layers described by
the attenuation and in situ measurements. Such a match allows the
best-defined comparison between attenuation and in situ results. An
example from ACE-Asia where the in situ extinction is computed as the
sum of scattering (from humidified nephelometry) and absorption (PSAP
instrument) is shown in Figure 9. Preliminary ACE-Asia results obtained
from a partial data set from both airborne platforms (Twin Otter and
C-130) indicate that total layer AODs calculated from the combination of
nephelometer and PSAP data are 20% - 40% less than those from AATS-6 or
-14 measurements (Redemann et al., 2002). We propose a detailed analysis
of all available ACE-Asia profiles including stratification of the
closure results with respect to aerosol types, relative humidity, flight
pattern during profile and other factors. Figure 10 shows an example
result from an ACE-Asia closure study (Wang et al., 2002) that compares
aerosol extinction from AATS-14 with values calculated from Mie theory
using measured size distributions and composition (used to determine the
complex refractive indices). This study, now submitted to *J. Geophys
Res*., is limited to four Twin Otter vertical profiles. We propose to
conduct the same type of analysis for as many C-130 and Twin Otter
vertical profiles as possible.

![](media/image9.pct){width="4.831944444444445in"
height="3.6256944444444446in"}

**Figure 9.** Aerosol optical depth (left) and extinction (right)
profile at 550 nm measured by AATS-14 and computed as the sum of
scattering (from humidified nephelometry) and absorption (PSAP
instrument) during aircraft ascent shown in Figure 8.

We also propose to apply the described closure analysis to the data
expected from the May 2003 SGP Aerosol IOP. This IOP will include
airborne measurements of extinction using the relatively new Continuous
Wave Cavity Ring-Down (CW-CRD) technology (Strawa et al., 2002).
Although the CW-CRD instrument does sample aerosol through an inlet it
directly measures in situ extinction, whereas typically in situ
extinction is derived from the sum of scattering and absorption measured
with two separate instruments (usually nephelometer and filter based
absorption). Further advantages of the CW-CRD technique are the absence
of filter artifacts, no heating of sample, no angular truncation error,
and no illumination errors.

We will extend the extinction closure analysis to include comparisons
with the numerous ground-based lidars deployed during ACE-Asia (e.g.,
Figure 10) and with the lidars operated routinely at SGP (e.g. Turner et
al., 2002, Welton et al., 2001).

During ACE-Asia considerable effort was devoted to coordinating aircraft
measurements with satellite overpasses. The list of sensors includes
AVHRR, GMS-5, MISR, MODIS, SeaWiFS, TOMS and ATSR-2. Airborne
sunphotometer measurements flown along transects near the land or ocean
surface in ACE-Asia provide aerosol optical depth spectra useful for
validating products from most of these sensors. At this point we have
performed limited comparisons with SeaWiFS (Figure 11) and MISR. These
indicate good agreement between SeaWiFS and AATS-14 if the Hsu et al.
(2002) algorithm is used. MISR currently tends to overestimate the AOD
with respect to AATS-14. Prompted by these early comparisons the MISR
team became aware of an instrument stray light problem, which is
currently being addressed (R. Kahn, personal communication). In the
framework of this proposal we hope to complete comparisons with all
sensors listed above.

Finally we propose to use our ACE-Asia AATS measurements to help
validate aerosol transport models such as CFORS (e.g., Uno et al.,
2001), GOCART (Chin et al., 2001), MATCH (Collins, 2002; Rasch and
Collins, 2001), and NAAPS (e.g., Bucholtz et al., 2002) in vertical
profiles and along horizontal

![](media/image10.png){width="4.477083333333334in"
height="3.9944444444444445in"}

**Figure 10.** Comparison of aerosol extinction derived from AATS-14
measurement, aerosol size distributions, and lidar measurements on R/V
Ron Brown during the ascent shown in Figure 8 (Wang et al., 2002a).

![](media/image11.pct){width="4.807638888888889in"
height="3.613888888888889in"}

**Figure 11.** Comparison of spectral aerosol optical depth on April 12,
2001 between AATS-14 and SeaWiFS, using standard and Hsu et al. (2002)
algorithms.

![](media/image12.png){width="6.747222222222222in"
height="3.089583333333333in"}

**Figure 12.** (a) June-August mean AOD at 500 nm derived from AVHRR
radiances by Husar et al. (1997). (b) 24h-average, cloud-free direct
shortwave aerosol radiative forcing at the tropopause derived from the
total aerosol optical depth map in (a). The radiative calculation
(Bergstrom and Russell, 1999) assumes an aerosol model based on
suborbital measurements in TARFOX and ACE-2. The choice of SSA shown
here, ω~a~=0.9, is based on radiative flux measurements; other
measurements yielded larger SSA (ω~a~\~0.92 to 0.98) (Russell et al.,
2002a). Bergstrom and Russell (1999) show results for ω~a~=1 and
ω~a~=0.9.

![](media/image13.jpeg){width="6.751388888888889in"
height="2.8048611111111112in"}**Figure 13.** (a) April 2001 monthly mean
AOD at 865 nm derived from SeaWiFS radiances using the algorithm of Hsu
et al. (2002). (b) 24h-average, cloud-free direct shortwave aerosol
radiative forcing at the surface in Wm^-2^, derived from total aerosol
optical depth shown in (a). The radiative calculation assumes an aerosol
model of dust over pollution aerosols. The relative amounts of dust and
pollution aerosols are adjusted pixel-by-pixel to force model Angstrom
exponent to equal the Angstrom exponent derived from the 4-wavelength
SeaWiFS radiances by Hsu et al. (2002).

gradients. An initial comparison between GOCART and AATS-14 has been
presented by Chin et al. (2001).

2.4 Prong C. Regional Forcing Assessments by Combining Satellite and
Suborbital Results

Our first regional assessment of aerosol radiative forcing (Bergstrom
and Russell, 1999) combined single-wavelength seasonal AOD maps of the
North Atlantic region with aerosol intensive properties derived from the
TARFOX and ACE-2 field programs. The AOD maps were derived by Husar et
al. (1997) from AVHRR reflectances; an example is shown in Figure 12a.
The aerosol intensive properties included optical depth wavelength
dependence across the solar spectrum, single scattering albedo,
hemispheric upscatter fraction, and relative vertical profile, all
synthesized from suborbital measurements by aircraft and ground sites
(including lidars). The satellite and suborbital inputs were combined in
a radiative transfer model (Bergstrom et al., 2002b) to derive maps of
cloud-free and all-sky radiative forcing; an example is shown in Figure
12b.

The goal of Prong C is to provide improved assessments of regional
radiative forcing by extending the approach of Bergstrom and Russell
(1999) to include the greatly enhanced measurement capabilities of newer
satellite sensors (e.g., SeaWiFS, MODIS, MISR, CERES) and new field
campaign data. For example, the following satellite-derived aerosol
products are available:

1.  Maps of aerosol optical depth from AVHRR
    (<ftp://ssa.noaa.gov/patmosa/>)

2.  Maps of a dust index from GMS-5 (dustnpgs at
    <http://www.joss.ucar.edu/cgi-bin/joss-catalog/ace-asia/products/index>)

3.  Maps of absorbing aerosol index from TOMS
    ([http://toms.gsfc.nasa.gov/aerosols/
    aerosols.html](http://toms.gsfc.nasa.gov/aerosols/aerosols.html))

4.  Maps of optical depth mode radius and the ratio of coarse to fine
    particles from MODIS (<http://modis-atmos.gsfc.nasa.gov/MOD04_L2/>);

5.  Maps of aerosol optical depth and Angstrom exponent from SeaWiFS
    (Hsu et al. (2002), available at

<http://code916.gsfc.nasa.gov/Missions/ACEASIA/satellite>)

6.  Maps of optical depths and the dominant aerosol type (dust, black
    carbon, sea salt and sulfate) (Higurashi and Nakajima, 2002; Hsu et
    al., 2002).

A primary focus of Prong C will be the Asian Pacific plume of desert
dust and pollution, which is one of the world's most climatically
significant aerosols. Initial studies on the radiative impact of Asian
aerosols on the basis of SeaWiFS-derived measurements of aerosol optical
depth and Angstrom exponent, as well as in situ data obtained during
ACE-Asia, have been presented by Russell et al. (2002b). Figure 13a
shows a map of the April 2001 monthly mean aerosol optical depth at 865
nm, derived from SeaWiFS-measured radiances using the algorithm of Hsu
et al. (2002). Using the map in Figure 13a in conjunction with the
satellite retrieved Angstrom parameter and assumptions regarding (i) the
aerosol single scattering albedo (and its wavelength dependence); (ii)
the asymmetry parameter (and its wavelength dependence) and (iii) the
partitioning of the relative contributions of mineral dust and
pollution-type aerosol to the total aerosol optical depth enables the
computation of corresponding maps of shortwave direct aerosol radiative
forcing of climate at the surface or at the top of the atmosphere (TOA).
An example for surface radiative forcing is shown in Figure 13b.

In computing the forcing in Figure 13b, we were limited to taking the
SeaWiFS-retrieved optical depth and Angstrom exponent and then applying
our own radiative transfer model. In this work we propose to utilize the
results from Parts A and B above to improve our estimates of the
radiative forcing of aerosols in the ACE-Asia region. In particular, the
results of the column closure studies (see Section 2.3) carried out in
support of ACE-Asia (e.g., Redemann et al., 2002) are expected to yield:

1.  Detailed information on the validity of aerosol absorption
    properties as measured by the PSAP instruments aboard the NCAR C-130
    and the CIRPAS Twin-Otter;

2.  The vertical distribution of aerosol extinction from comparison of
    sunphotometer- and in situ- derived aerosol properties (cf. Figures
    8-10);

3.  Information on the vertical distribution of aerosol species based on
    the vertical distribution of Angstrom parameters.

This information will be combined with the observed absorption results
of Prong A (Section 2.2) to constrain the inputs to the radiative
transfer model. For example, the aerosol observed during the ACE Asia
campaign was extremely complex mixture of dust and urban pollution.
Using the detailed radiative transfer model described in Section 2.2.2,
we will compute the effect of the multi-modal aerosol on the observed
satellite radiances. (The included multiple scattering code, DISORT, can
compute radiances as well as fluxes.)

To avoid the inconsistency in using one model of aerosol radiative
properties to convert the satellite-measured radiances into aerosol
optical depth and a different model to convert the aerosol optical depth
to aerosol radiative forcing, we also propose to collaborate with the
teams of A. Higurashi (National Institute of Environmental Studies,
Ibaraki, Japan) and T. Nakajima (Univ. of Tokyo, Tokyo, Japan). We will
work with them to develop an aerosol model for SeaWiFS measurements that
will be used in both the conversion of satellite radiances to AOD and in
the conversion of AOD to aerosol radiative forcing of climate. We will
also perform sensitivity tests to assess how changing aerosol model
parameters affects derived forcing, both when using the same model for
both steps, and when using different models in each step. This should
enable us to more accurately estimate the aerosol radiative forcing and
the associated uncertainties. A major objective will be to quantify and
reduce the uncertainties in aerosol radiative-climatic effects cited by
NACIP (Ramanathan et al., 2002)

Initial comparisons between various satellite sensors (e.g., MODIS vs.
SeaWiFS) indicate considerable differences in temporally-averaged fields
of aerosol optical depth. Such differences could be due to the complex
interaction of aerosols and clouds in the western Pacific region and the
associated complications in satellite cloud screening algorithms, or due
to inadequate modeling of the mixtures of various aerosol types in
satellite retrieval algorithms. Hence, as a second element of this task,
we propose to compare the aerosol optical depth fields derived from
various satellite sensors (MODIS, SeaWiFS, MISR, AVHRR) as they are
relevant to the calculation of regional mean aerosol radiative forcing
of climate. Based on the comparison of instantaneously measured aerosol
optical depth between suborbital and satellite sensors proposed in
Section 2.3, we expect to aid in explaining any differences found
between aerosol products from different satellite sensors.

**2.5 Proposed Tasks and Timetable**

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

**2.5.1 Year One (March 1, 2003 - February 28, 2004)**

**2.5.1.1 Task A1:** Derive aerosol absorption and SSA spectra for a
representative variety of aerosol types and conditions using the
ACE-Asia Twin Otter SSFR and AATS-14 data sets. Assess uncertainties,
taking into account radiometer tilt and all other significant error
sources. Compare results to those from other ACE-Asia measurements and
the literature for similar aerosols. Begin corresponding analyses for
the May 2003 SGP Aerosol IOP data set, to the extent permitted by the
state of data reduction for that experiment.

**2.5.1.2 Task A2:** Provide results of Task A1 to Prongs B and C and to
the community in summary data files, presentations and publications.

**2.5.1.3 Task B1:** Perform extinction closure studies for a
representative variety of ACE-Asia aerosols by comparing extinction and
optical depth spectra and profiles measured by airborne sunphotometer to
results from airborne in situ, lidar, and satellite methods. Synthesize
results in terms of uncertainties in key parameters as a function of
aerosol and surface condition (e.g., over water vs. land) and
measurement or retrieval type.

**2.5.1.4 Task B2:** Provide results of Task B1 to Prongs A and C and to
the community in summary data files and in presentations and
publications.

**2.5.1.3 Task C1:** Assess aerosol radiative forcing for the ACE-Asia
region by combining satellite and suborbital results, including those
from Prongs A and B. Quantify uncertainties via sensitivity studies that
combine uncertainties in input parameters with sensitivities of outputs
to inputs. Devote special efforts to cloud effects, both on the
satellite retrievals and on radiative flux changes. Quantify the benefit
of using a consistent model in satellite retrievals and flux-change
calculations.

**2.5.1.4 Task C2:** Provide results of Task C1 to the community in
summary data files and in presentations and publications.

**2.5.2 Years Two and Three (March 1, 2004 - February 28, 2006)**

**2.5.2.1 Task A3:** Complete the publication of the ACE-Asia absorption
results. Complete the analysis, presentation, and publication of SGP
Aerosol IOP absorption results, including an assessment of the accuracy
improvement resulting from the stabilized radiometer platform.
Synthesize the overall results in terms of aerosol absorption and SSA
spectra for major aerosol types. Compare to results of other
measurements and previous studies, sorting results by aerosol type.

**2.5.2.2 Task B3:** Complete the publication of the ACE-Asia extinction
closure results. Complete the analysis, presentation, and publication of
SGP Aerosol IOP results, including a synthesis of results in terms of
uncertainties in key parameters as a function of aerosol and surface
condition (e.g., over water vs. land) and measurement type, including
absorption results of Prong A.

**2.5.2.3 Task C3:** Complete the publication of the ACE-Asia regional
forcing results, and the analysis, presentation, and publication of SGP
Aerosol IOP results. Include a synthesis of results in terms of
satellite retrieval type, aerosol type, surface condition (e.g., over
water vs. land) and cloud condition. Assess implications for forcing by
aerosol type in the major aerosol-influenced regions of the world.
Emphasize quantification and reduction of the uncertainties cited by
NACIP (Ramanathan et al., 2002).

2.6. References

Ackerman, A. S., O. B. Toon, D. E. Stevens, A. J. Heymsfield, V.
Ramanathan, E. J. Welton, Reduction of tropical cloudiness by soot,
*Science*, *288*, 1042-1047, 2000.

Ackerman, S.A. and S.K. Cox: Shortwave radiative parameterization of
large atmospheric aerosols: dust and water clouds. *J. Geophys. Res.*,
**93**, 11063-11073, 1988.

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.

Bergstrom, R. W., P. B. Russell, and P. Hignett, Wavelength dependence
of the absorption of black carbon particles: Predictions and results
from the TARFOX experiment and implications for the aerosol single
scattering albedo, *J. Atmos. Sci., 59,* 568-578, 2002a.

Bergstrom, R.W., P. Pilewskie, B. Schmid, and P.B. Russell, Comparison
of measured and predicted aerosol radiative effects during SAFARI 2000,
*J. Geophys. Res.*, submitted, 2002b.

Bucholtz, A., D. L. Westphal, and S. A. Christopher, The springtime
radiative forcing of aerosols over the Eastern Asia/Western Pacific
region, Paper P1.7, 11^th^ Conf. Atmos. Rad., Amer. Meteor. Soc., Ogden,
Utah, 3-7 June 2002.

Chin, M., P. Ginoux, P. Flatau, T. Anderson, S. Masonis, P. Russell, B,
Schmid, J. Livingston, J. Redemann, R. Kahn, O. Torres, and C. Hsu,
Transport of aerosols from Asia and their radiative effects over the
Western Pacific: A 3-D model study for ACE-Asia Experiment during Spring
2001, *EOS Trans. AGU*, 82 (47), Fall Meet. Suppl., Abstract A32D-06,
2001.

Colarco, P. R., O. B. Toon, J. S. Reid, J. M. Livingston, P. B. Russell,
J. R. Redemann, B. Schmid, H. B. Maring, D. Savoie, J. Welton, J. R.
Campbell, B. N. Holben, and R. Levy, Saharan dust transport to the
Caribbean during PRIDE: Part 2. Transport, vertical profiles, and
deposition in simulations of in situ and remote sensing observations,
*J. Geophys. Res*., submitted 2002.

Collins, D. R., Jonsson, H. H., Seinfeld, J. H., Flagan, R. C., Gassó,
S., Hegg, D., Russell, P. B., Livingston, J. M., Schmid, B., Öström, E.,
Noone, K. J., and Russell, L. M. In situ aerosol size distributions and
clear column radiative closure during ACE 2. *Tellus B 52*, 498-525,
2000.

Collins, W. D., Effects of clouds on direct radiative forcing by
absorptive aerosols, Paper 1.3, 11^th^ Conf. Atmos. Rad., Amer. Meteor.
Soc., Ogden, Utah, 3-7 June 2002.

Crowther, B.G., The design, construction, and calibration of a spectral
diffuse global irradiance meter. Ph.D. Thesis, University of Arizona,
140 pp., 1997.

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. *J. Geophys.
Res*., *105*, 9917-9933, 2000.

Ferrare, R., Ismail, S.; Browell, E.; Brackett, V.; Kooi, S.; Clayton,
M.; Hobbs, P. V.; Hartley, S.; Veefkind, J. P.; Russell, P.; Livingston,
J.; Tanre, D., Hignett, P., Comparisons of LASE, aircraft, and satellite
measurements of aerosol optical properties and water vapor during
TARFOX, *J. Geophys. Res*., *105*, 9935-9947, 2000b.

Flamant, C., J. Pelon, P. Chazette, V. Trouillet, P. K. Quinn, R.
Frouin, D. Bruneau, J. F. Leon, T. Bates, J. Johnson, and J. Livingston,
Airborne lidar measurements of aerosol spatial distribution and optical
properties over the Atlantic Ocean during a European pollution outbreak
of ACE-2. *Tellus B 52*, 662-677, 2000.

Gatebe, C. K., M. D. King, S. Platnick, G. T. Arnold, E. F. Vermote, and
B. Schmid, Airborne Spectral Measurements of Surface-Atmosphere
Anisotropy for Several Surfaces and Ecosystem over Southern Africa, *J.
Geophys. Res.*, submitted, 2002.

Gassó, S., Hegg, D. A., Covert, D. S., Noone, K., Öström, K., Schmid,
K., Russell, P. B., Livingston, J. M., Durkee, P. A., and Jonsson, H.
Influence of humidity on the aerosol scattering coefficient and its
effect on the upwelling radiance during ACE-2. *Tellus B 52*, 546-567,
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.* 105, 9859-9886, 2000.

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.

Higurashi, A. and T. Nakajima, Aerosol type classification with SeaWiFS
four-channel radiance data. Presented at AMS Radiation Conference, Ogden
UT, 3-7 June 2002.

Hsu, N. C., Tsay, S, Herman, J Holben, B, Comparisons of satellite
retrieval of aerosol properties from SeaWiFS and TOMS to the AERONET
measurements, *EOS Trans. AGU*, 82 (47), Spring Meet. Suppl., Abstract
A51B-03, 2002.

Huebert, B., et al., ACE-Asia Project Prospectus, 30 December 1999.
Available at
[[http://saga.pmel.noaa.gov/aceasia/prospectus2000/]{.underline}](http://saga.pmel.noaa.gov/aceasia/si_nsf/index.html)

Husar, R. B., J. M. Prospero and L. L. Stowe, Characterization of
tropospheric aerosols over the oceans with the NOAA advanced very high
resolution radiometer optical thickness operational product*, J.
Geophys. Res.,* 102, 16,889--16,909, 1997.

Ingold, T., B. Schmid, et al., Modeled and empirical approaches for
retrieving columnar water vapor from solar transmittance measurements in
the 0.72, 0.82 and 0.94-um absorption bands. *J. Geophys. Res.,
105*(D19), 24327-24343, 2000.

Ismail S, Browell EV, Ferrare RA, Kooi SA, Clayton MB, Brackett VG,
Russell PB, LASE measurements of aerosol and water vapor profiles during
TARFOX, *J. Geophys. Res*., *105*, 9903-9916, 2000.

Kiedron P., J. Michalsky, B. Schmid, et al., A robust retrieval of water
vapor column in dry Arctic conditions using the Rotating Shadowband
Spectroradiometer. J. Geophys. Res., 106(D20), 24007-24016, 2001.

Kuzmanoski, M., G. Box, M. Box, P. Russell, B. Schmid, Aerosol
properties from international field campaigns, 9th National Conference,
Australian Meteorological and Oceanographic Society, University of
Melbourne, 18-20 February, 2002.

Levy, J., Aerosol-Climate Interactions Program - (ACIP), *Program
Announcement for Office of Global Programs, National Oceanic and
Atmospheric Administration*,
<http://www.ogp.noaa.gov/c&gc/ao/2003/index.htm>, 2002a.

Levy, J., Aerosol-Climate Interactions Program (ACIP) Home Page,
<http://www.ogp.noaa.gov/mpe/acip/index.htm>, 2002b.

Levy, J., New findings highlight the significance of aerosols in the
Earth's Climate System, [http://www.ogp.noaa.gov/
aboutogp/spotlight/aerosols/aero9_00.htm](http://www.ogp.noaa.gov/aboutogp/spotlight/aerosols/aero9_00.htm),
2002c.

Levy, R. C. L. Remer, D. Tanré, Y. Kaufman, C. Ichoku, B. Holben, J.
Livingston, P. Russell, H. Maring, Evaluation of the MODIS retrievals of
dust aerosol over the ocean during PRIDE, *J. Geophys. Res.*, submitted,
2002.

Livingston, J. M., et al. (w. B. Schmid, P. B. Russell), 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 B*, *52*, 594-619, 2000.

Livingston, J.M., et al., ACE-Asia Aerosol Optical Depth and Water Vapor
Measured by Airborne Sunphotometers and Related to Other Measurements
and Calculations, Fall AGU Meeting, San Francisco, 10-14 December 2001.

Livingston, J. M., et al., Airborne sunphotometer measurements of
aerosol optical depth and columnar water vapor during the Puerto Rico
Dust Experiment, and comparison with land, aircraft, and satellite
measurements, *J. Geophys. Res.*, submitted, 2002.

Kurucz, R.L., Synthetic infrared spectra, in Infrared Solar Physics, IAU
Symp, 154, edited by D.M. Rabin and J.T. Jeffries, Kluwer Acad.,
Norwell, MA, 1992 (Available on the LBLRTM web site).

Magi, B. I., P. V. Hobbs, B. Schmid, and J. Redemann, Vertical profiles
of light scattering, light absorption and single scattering albedo
during the dry, biomass burning season in southern Africa and
comparisons of in situ and remote sensing measurements of aerosol
optical depths, *J. Geophys. Res.*, submitted, 2002.

Matsumoto, T., P. Russell, C. Mina, W. Van Ark, and V. Banta, Airborne
tracking sunphotometer, *J. Atmos. Ocean. Tech.*, *4*, 336-339, 1987.

McGill M., D. Hlavka, W. Hart, J. Spinhirne, S. Scott, and B. Schmid.
The Cloud Physics Lidar: Instrument Description and Initial Measurement
Results. *Appl. Opt*. 2002 (in press).

Mlawer, E.J., et al., Radiative transfer for inhomogeneous atmospheres:
RRTM, a validated correlated-k model for the longwave. *J. Geophys.
Res., 102*, 4353-4356, 1997.

National Academy of Sciences Committee on the Science of Climate Change,
*Climate Change Science: An Analysis of Some Key Questions,* ISBN
0-309-07574-2, National Academy Press (http://www.nap.edu), 2001.

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

Pilewskie, P., J. Pommier, R. Bergstrom, W. Gore, S. Howard, M.
Rabbette, B. Schmid, et al., Solar spectral radiative forcing during the
South African Regional Science Initiative. *J. Geophys. Res*. Accepted
for publication, 2002a.

Pilewskie, P., R. Bergstrom, M. Rabbette, J.Pommier, and S. Howard,
Cloud solar spectral spectral irradiance during ARESEII. *J. Geophys.
Res*., Submitted, 2002b.

Pilewskie, P., R. Bergstrom, J. Reid, H. Jonnson, S. Howard, and J.
Pommier, J. Livingston, and P. Russell. Solar radiative forcing by
Saharan dust during the Puero Rico Dust Experiment. *J. Geophys. Res*.
Submitted, 2002c.

Quijano A.L., I.N**.** Sokolik and O.B. Toon. Radiative heating rates
and direct radiative forcing by mineral dust in cloudy conditions. *J.
Geophys. Res. , D10*, 12,207-12,219, 2000.

Rabbette , M. and P. Pilewskie, Multivariate analysis of solar spectral
irradiance measurements. *J. Geophys. Res*., 106, D9, 9685-9696 (2001).

Rabbette, M. and P. Pilewskie, Principal component analysis of Arctic
solar irradiance spectra. *J. Geophys. Res*. in press, 2002.

Raes, F., Bates, T., McGovern, F., van Liedekerke, M., The Second
Aerosol Characterization Experiment (ACE-2): general overview and main
results. *Tellus* *52B*, 111-125, 2000.

Ramanathan, V, et al., Indian Ocean Experiment: An integrated analysis
of the climate forcing and effects of the great Indo-Asian haze, *J.
Geophys. Res., 160*, 28,371-28,398, 2001.

Ramanathan, V., T. S. Bates, J. E. Hansen, D. J. Jacob, Y. J. Kaufman,
J. E. Penner, M. J. Prather, S. E. Schwartz, and J. H. Seinfeld,
*National Aerosol-Climate Interactions Program (NACIP), A National
Research Imperative*, White Paper, <http://www-NACIP/ucsd.edu>, 2002.

Rasch, P. J., and W. D. Collins, Estimating natural variability of Asian
aerosols; Relationship of ACE-Asia to the 1990s, *EOS Trans. AGU*, 82
(47), Fall Meet. Suppl., Abstract A12B-09, 2001.

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, *J.
Geophys. Res.* *105*, 9949-9970, 2000a.

Redemann, J., et al. (w. P. B. Russell), Case studies of the vertical
structure of the shortwave direct aerosol radiative forcing during
TARFOX, *J. Geophys. Res*., *105,* 9971-9979, 2000b.

Redemann, J., P.B. Russell, and P. Hamill, Dependence of aerosol light
absorption and single scattering albedo on ambient relative humidity for
sulfate aerosols with black carbon cores, *[J. Geophys.
Res.]{.underline}*, *106*, 27,485-27,495, 2001a.

Redemann, J., B. Schmid, P.B. Russell, J.M. Livingston, J.A. Eilers,
S.A. Ramirez, and R. Kahn, Airborne sunphotometry of aerosol optical
depth and columnar water vapor during ACE-Asia, American Association for
Aerosol Research Annual Meeting, Portland, Oregon, 15-19 October 2001b.

Redemann, J., B. Schmid, P. Russell, J. Livingston, et al., Towards a
determination of aerosol radiative effects in the Pacific Basin
troposphere based on aerosol extinction and optical depth closure
studies aboard the NCAR C-130 in ACE-Asia, First ACE-Asia Data Workshop,
Pasadena, CA, 29 October-1 November 2001c.

Redemann, J., B. Schmid, J. M. Livingston, P. B. Russell, et al.,
Airborne Sunphotometer Measurements of Aerosol Optical Depth and Water
Vapor in ACE-Asia and their Comparisons to Correlative Measurements and
Calculations, *Abstracts*, 11^th^ Conference on Atmospheric Radiation,
American Meteorological Society, Ogden, UT, June 3-7, pp. 35, 2002.

Reid, J. S., D. L. Westphal, J. Livingston, D. S. Savoie, H. B. Maring,
P. Pilewskie, and D. Eleuterio, The vertical distribution of dust
transported into the Caribbean during the Puerto Rico Dust Experiment*,
Geophys. Res. Lett*., (in press), 2002.

Revercomb H.E., D.D. Turner, D.C. Tobin, R.O. Knuteson, W.F. Feltz, B.
Balsley, J. Barnard, J. Bösenberg, S. Clough, D. Cook, R. Ferrare, J.
Goldsmith, S. Gutman, R. Halthore, B. Lesht, J. Liljegren, H. Linné, J.
Michalsky, V. Morris, W. Porch, S. Richardson, B. Schmid, et al., The
Atmospheric Radiation Measurement (ARM) Program's Water Vapor Intensive
Observation Periods: Overview, accomplishments, and future challenges.
*Bull. Amer. Meteor. Soc.* (submitted), 2001.

Russell, P. B., and J. Heintzenberg, An overview of the ACE 2 Clear Sky
Column Closure Experiment (CLEARCOLUMN), *Tellus B*, *52*, 463-483,
2000.

Russell, P. B., P. V. Hobbs, and L. L. Stowe, Aerosol properties and
radiative effects in the United States east coast 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.

Russell, P. B., B. Schmid, J. Redemann, J. M. Livingston, R. W.
Bergstrom, P. Pilewskie, et al., Airborne sunphotometer studies of
aerosol properties and effects, including closure among satellite,
suborbital remote, and in situ measurements, 8th Scientific Assembly of
IAMAS, Innsbruck, Austria, 10-18 July 2001a.

Russell, P. B, F. P. J. Valero, P. J. Flatau, M. Bergin, B. Holben, T.
Nakajima, P. Pilewskie, R. Bergstrom, B. Schmid , J. Redemann, J.
Livingston, et al., Overview of ACE-Asia Spring 2001 Investigations on
Aerosol Radiative Effects and Related Aerosol Properties, Fall AGU
Meeting, San Francisco, 10-14 December 2001b.

Russell, P. B., J. Redemann, B. Schmid, R. W. Bergstrom, J. M.
Livingston, et al., Comparison of aerosol single scattering albedos
derived by diverse techniques in two North Atlantic experiments, *J.
Atmos. Sci.,* *59*, 609-619, 2002a.

Russell, P.B., et al., Overview of ACE-Asia Spring 2001 Investigations
on Aerosol-Radiation Interactions, *Abstracts*, 11^th^ Conference on
Atmospheric Radiation, American Meteorological Society, Ogden, UT, June
3-7, p. 8, 2002b.

Schmid, B., J. J. Michalsky, R. N. Halthore, M. C. Beauharnois, L. C.
Harrison, J. M. Livingston, P. B. 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*., *17*, 2725-2728, 1999.

Schmid, B., J. M. Livingston, P. B. Russell, et al., 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*, *52*, 568-593, 2000.

Schmid B., et al., Comparison of columnar water-vapor measurements from
solar transmittance methods. *Applied Optics,* *40*, 1886-1896, 2001.

Schmid B., J. Redemann, P. B. Russell, P. V. Hobbs, D. L. Hlavka, M. J.
McGill, B. N. Holben, E. J. Welton, J. Campbell, O. Torres, R. A. Kahn,
D. J. Diner, et al., Coordinated airborne, spaceborne, and ground-based
measurements of massive, thick aerosol layers during the dry season in
Southern Africa, *J. Geophys. Res*., accepted, 2002.

Stamnes, K., S.-C. Tsay, W. Wiscombe and K. Jayaweera, A numerically
stable algorithm for discrete-ordinate-method radiative transfer in
multiple scattering and emitting layered media, *Appl Opt 27*,
2502-2509, 1988.

Strawa A.W., R. Castaneda, T. Owano, D. S. Baer, and B. A. Paldus, The
measurement of aerosol optical properties using continuous wave cavity
ring-down techniques, submitted to *J. Atmos. Oceanic. Tech.*, 2002.

Turner, D.D., R.A. Ferrare, L.A. Heilman, W.F. Feltz, and T. Tooman,
Automated retrievals of water vapor and aerosol profiles over Oklahoma
from an operational Raman lidar, *J. Atmos. Oceanic. Tech*., 19, 37-50,
2002.

Uno, I*.,* M. Chin, W. Collins, P. Ginoux, P. Rasch, G. R. Carmichael,
and J. J Yienger, ACE-Asia chemical transport modeling overview, *EOS
Trans. AGU*, 82 (47), Fall Meet. Suppl., Abstract A22A-0101, 2001.

Wang, J., R. C. Flagan, J. H. Seinfeld, H. H. Jonsson, D. R. Collins, P.
B. Russell, B. Schmid, J. Redemann, J. M. Livingston, S. Gao, D.A. Hegg,
E.J. Welton, and D. Bates, Clear-column radiative closure during
ACE-Asia: Comparison of multiwavelength extinction derived from particle
size and composition with results from sunphotometry J. Geophys. Res.,
submitted, 2002a.

Wang, J, S. A. Christopher, J. S. Reid, H. B. Maring , D. L. Savoie , B.
N. Holben, J. M. Livingston, P. B. Russell and S-K. Yang, GOES-8
retrieval of dust aerosol optical thickness over the Atlantic Ocean
during PRIDE, *J. Geophys. Res.*, submitted, 2002b.

Welton, E. J., Voss, K. J., Gordon, H. R., H. Maring, Smirnov, A.,
Holben, B., Schmid, B., Livingston, J. M., Russell, P. B., et al.,
Ground-based lidar measurements of aerosols during ACE 2: Instrument
description, results, and comparisons with other ground-based and
airborne measurements. *Tellus B 52*, 636-651, 2000.

Welton, E. J., J. R. Campbell, J. D. Spinhirne, and V. S. Scott,
\"Global monitoring of clouds and aerosols using a network of
micro-pulse lidar systems \", in Lidar Remote Sensing for Industry and
Environmental Monitoring, U. N. Singh, T. Itabe, N. Sugimoto, (eds.),
Proc. SPIE, 4153, 151-158, 2001.

Xu, J., M.H. Bergin, R. Greenwald, P.B. Russell, Direct aerosol
radiative forcing in the Yangtze delta region of China: observation and
model estimation, *J. Geophys. Res.*, submitted, 2002.

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

Dr. Philip Russell will be Lead Principal Investigator. As such, he will
supervise the work, lead the planning, and participate in the analyses,
as well as selected presentations and publications. He will be
responsible for the completion of the work within budget and schedule.
Drs. Peter Pilewskie, Beat Schmid and Jens Redemann will be Co-PIs for
Prongs A, B, and C, respectively, each responsible for leading his
respective prong and coordinating it with the others. Dr. Robert
Bergstrom will play key roles in Prongs A and C, including leading and
facilitating the use of his radiative transfer model to (i) derive
single scattering albedos from SSFR and AATS measurements and (ii)
calculate regional radiative forcings. Ames will furnish additional
personnel necessary to accomplish the research.

**(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, 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 Teams for NASA's Earth Observing System
Inter-Disciplinary Science (EOS-IDS) and the Asian Pacific Regional
Aerosol Characterization Experiment (ACE-Asia) of the International
Global Atmospheric Chemistry (IGAC) Project.

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

Previously, Mission Scientist for ACE-Asia C-130 flights addressing
aerosol-radiation interactions. Co-coordinator for the CLEARCOLUMN
component of IGAC's Second Aerosol Characterization Experiment (ACE-2).
Coordinator for IGAC's Tropospheric Aerosol Radiative Forcing
Observational Experiment (TARFOX). Member, Science Teams for SAGE II and
SAGE III (satellite sensors of stratospheric aerosols, ozone, nitrogen
dioxide, and water vapor). Member, Science Team for Global Aerosol
Climatology Project (GACP).

Previously, Editor-in-Chief (1994-95) and Editor (1993, 1996),
*Geophysical Research Letters*. Chair, American Meteorological Society
Committee on Laser Atmospheric Studies (1979-82). Member, AMS Committee
on Radiation Energy (1979-81). Member, National Research Council
Committee on Army Basic Research (1979-81).

Previously, Project Scientist, Small High-Altitude Science Aircraft
(SHASA) Project to develop the Perseus A Remotely Piloted Aircraft (RPA,
1992-94). 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).

NASA Exceptional Service Medal (1988, for managing
Stratosphere-Troposphere Exchange Project). NASA Space Act Award (1989,
for invention of Airborne Autotracking Sunphotometer). Member, Phi Beta
Kappa and Sigma Xi.

**SELECTED PUBLICATIONS (from 94 peer-reviewed papers)**

Russell, P. B., et al., Comparison of aerosol single scattering albedos
derived by diverse techniques in two North Atlantic experiments, *J.
Atmos. Sci.,* *59*, 609-619, 2002.

Russell, P. B., and J. Heintzenberg, An overview of the ACE-2 Clear Sky
Column Closure Experiment (CLEARCOLUMN), *Tellus B 52*, 463-483, 2000.

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, 1999.

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.

Russell, P. B., et al. 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., et al. 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., L. Pfister, and H.B. Selkirk, \"The tropical experiment
of the Stratosphere-Troposphere Exchange Project (STEP): Science
objectives, operations, and summary findings, *J. Geophys. Res.*, *98*,
8563-8589, 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., et al., Satellite and correlative measurements of the
stratospheric aerosol: III. Comparison of measurements by SAM II, SAGE,
dustsondes, filters, impactors, and lidar, *J. Atmos. Sci.*, *41*,
1791-1800, 1984.

**(b) Peter Pilewskie**

**Abbreviated Curriculum Vitae**

NASA Ames Research Center

MS 245-4, Moffett Field CA 94035-1000

**Education:**

B.S., Meteorology, Pennsylvania State University, 1983

M.S., Atmospheric Science, University of Arizona, 1986

Ph.D., Atmospheric Science, University of Arizona, 1989

**Professional Experience:**

Radiation Group Leader, Atmospheric Physics Branch, NASA Ames Research
Center, 1994-present

Research Scientist, Atmospheric Physics Branch, NASA Ames Research
Center, 1989-1994

Research Assistant, Institute of Atmospheric Physics, University of
Arizona, 1983-1989

**Professional Activities:**

Member, Atmospheric Radiation Measurement (ARM) Enhanced Shortwave
Experiment (ARESE) II Science Team

Member, Solar Radiation and Climate Experiment (SORCE), 1999-present

Member, Triana Science Team, 1998-present

Member, Global Aerosol Climatology Program (GACP), 1998-present

Member, Atmospheric Radiation Measurement Program (ARM) Science Team,
1997-present

Member, International Global Atmospheric Chemistry (IGAC), Focus on
Atmospheric Aerosols, Direct Aerosol Radiative Forcing Activity,
1995-1999

Member, First International Satellite Cloud Climatology Program (ISCCP)
Regional Experiment, Phase III (FIRE III) Science Team, 1994-present

# Science Team Leader, International Global Aerosol Program (IGAP), Radiative Effects of Aerosols, 1993

**Professional Honors:**

NASA Exceptional Scientific Achievement Medal, 1997

NASA Group Achievement Award, FIRE Phase II Science and Operations Team,
1997

NASA Ames Honor Award, Scientist, 1995

**Selected Recent Publications:**

Pilewskie, P., J. Pommier, R. Bergstrom, W. Gore, S. Howard, M.
Rabbette, B. Schmid, P.V. Hobbs, and S.C. Tsay, Solar spectral radiative
forcing during the South African Regional Science Initiative. *J.
Geophys. Res*. accepted, 2002.

Pilewskie, P., R. Bergstrom, M. Rabbette, J.Pommier, and S. Howard,
Cloud solar spectral spectral irradiance during ARESEII. *J. Geophys.
Res*. submitted, 2002.

Pilewskie, P., R. Bergstrom, J. Reid, H. Jonsson, S. Howard, and
J.Pommier, J. Livingston, and P. Russell. Solar radiative forcing by
Saharan dust during the Puero Rico Dust Experiment. *J. Geophys. Res*.
submitted, 2002.

Reid, J. S., D. L. Westphal, J. Livingston, D. S. Savoie, H. B. Maring,
P. Pilewskie, and D. Eleuterio, The vertical distribution of dust
transported into the Caribbean during the Puerto Rico Dust Experiment*,
Geophys. Res. Lett*., in press, 2002.

Rabbette , M. and P. Pilewskie, Multivariate analysis of solar spectral
irradiance measurements. *J. Geophys. Res*., 106, D9, 9685-9696, 2001.

Rabbette , M. and P. Pilewskie, Principal component analysis of Arctic
solar irradiance spectra. *J. Geophys. Res*. in press, 2002.

Pilewskie, P., M. Rabbette, 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.* **25**, 137, 2000.

**(c) Beat Schmid**

**Abbreviated Curriculum Vitae**

Bay Area Environmental Research Institute

560 Third Street West, Sonoma, CA 95476

## Education

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

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

## Professional Experience

[Bay Area Environmental Research Institute]{.underline}, Sonoma, CA
(1997-Present): Senior Research Scientist

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

[University of Bern]{.underline}, Switzerland (1989-1997): Postdoctoral
Researcher (1995-1997)

## Scientific Contributions

-   9 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~.

-   Participated with the NASA Ames Airborne Sun photometers in ACE-2
    (North Atlantic Regional Aerosol Characterization Experiment, 1997),
    SAFARI 2000 (Southern African Regional Science Initiative; 2000),
    and ACE-Asia (Asian Pacific Regional Aerosol Characterization
    Experiment; 2001). Extensive comparison of results (closure studies)
    with other techniques: lidar, optical particle counters,
    nephelometers, and satellites.

-   Participated with the NASA Ames Airborne Sun photometers in the US
    Dept. of Energy, Atmospheric Radiation Measurement (ARM) program
    integrated Fall 1997 and Fall 2000 intensive observation periods in
    Oklahoma. Led sun photometer intercomparison. Extensive comparison
    of water vapor results with radiosondes, microwave radiometers,
    lidar, and Global Positioning System.

-   Participated with NASA Ames Cavity Ringdown instrument in Reno
    Aerosol Optics Study (June, 2002).

## Scientific Societies/Editorships

-   Associate Editor, *Journal of Geophysical Research* (2002- )

-   Member, American Geophysical Union and American Meteorological
    Society

## Selected Publications (from 20 published or in press, plus 8 recently submitted)

Schmid B., et al., Coordinated airborne, spaceborne, and ground-based
measurements of massive, thick aerosol layers during the dry season in
Southern Africa, *J. Geophys. Res.,* accepted, 2002.

Livingston, J. M., et al., incl, B. Schmid, Airborne sunphotometer
measurements of aerosol optical depth and columnar water vapor during
the Puerto Rico Dust Experiment, and comparison with land, aircraft, and
satellite measurements, *J. Geophys. Res.*, submitted, 2002.

Wang, J., et al., incl, B. Schmid, Clear-column radiative closure during
ACE-Asia: Comparison of multiwavelength extinction derived from particle
size and composition with results from sunphotometry J. Geophys. Res.,
submitted, 2002.

Pilewskie, P., et al., incl, B. Schmid, Solar Spectral Radiative Forcing
During the South African Regional Science Initiative, *J. Geophys.
Res.*, submitted, 2002.

Schmid B., et al., Comparison of columnar water-vapor measurements from
solar transmittance methods. *Applied Optics,* Vol. 40, No. 12,
1886-1896, 2001.

Schmid, B., et al., 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 52, 568-593, 2000.

Schmid B., et al., Comparison of Aerosol Optical Depth from Four Solar
Radiometers During the Fall 1997 ARM Intensive Observation Period,
*Geophys. Res. Lett*., *26*(17), 2725-2728, 1999.

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 Geosci. Remote. Sens*., 35(1),
172-182, 1997.

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. *J. Geophys. Res., 101*(D5), 9345-9358, 1996.

Schmid, B., and C. Wehrli, Comparison of Sun Photometer Calibration by
Langley Technique and Standard Lamp. *Appl. Opt.,* *34*(21), 4500-4512,
1995.

**(d) Jens Redemann**

**Abbreviated Curriculum Vitae**

Bay Area Environmental Research Institute, 560 Third Street West,
Sonoma, CA 95476

# PROFESSIONAL EXPERIENCE

  ------------------- ---------------- -----------------------------------
  Senior Research     BAERI, Sonoma,   April 1999 to present
  Scientist           CA               

  Research Assistant  UCLA, CA         May 1995 to March 1999

  Lecturer            UCLA, CA         Jan. 1999 to present

  Research Assistant  FU Berlin,       June 1994 to April 1995
                      Germany          
  ------------------- ---------------- -----------------------------------

# EDUCATION

+----------------------------------+-----------------------------------+
| Ph.D. in Atmospheric Sciences,   | > 1999                            |
| UCLA.                            |                                   |
+----------------------------------+-----------------------------------+
| M.S. in Atmospheric Sciences,    | > 1997                            |
| UCLA.                            |                                   |
+----------------------------------+-----------------------------------+
| M.S. in Physics, FU Berlin,      | > 1995                            |
| Germany.                         |                                   |
+----------------------------------+-----------------------------------+

# 

# RELEVANT RESEARCH EXPERIENCE

-   Principal Investigator for the participation of AATS-14 in the CLAMS
    (Chesapeake Lighthouse Aerosol Measurements for Satellites)
    satellite validation study (July 2001). Responsible for proposal
    writing, experiment design and instrument integration. Member of
    CLAMS Science Team.

-   Participated in the SAFARI-2000, ACE-Asia field experiments,
    investigating aerosol-climate interactions.

-   Developed a coupled aerosol microphysics and chemistry model to
    study the dependence of aerosol absorption and single scattering
    albedo on ambient relative humidity.

-   Related airborne measurements using sunphotometers, lidar (light
    detection and ranging) systems and flux radiometers to in situ
    measurements of atmospheric (mineral dust) aerosols and gases and
    modeled the local radiative transfer in Earth's atmosphere.

```{=html}
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```
-   Specialized course work in atmospheric sciences, geophysical fluid
    dynamics, cloud physics, radiative transfer and remote sensing.

# HONORS / ORGANIZATIONS

+-----------------------------------------------------------+----------+
| Invited Speaker at the Atmospheric Chemistry Colloquium   | #### J   |
| for Emerging Senior Scientists (ACCESS V)                 | une 1999 |
+-----------------------------------------------------------+----------+
| Outstanding Student Paper Award, American Geophysical     | 1998     |
| Union - fall meeting                                      |          |
+-----------------------------------------------------------+----------+
| NASA Global Change Research Fellowship Awards             | 1        |
|                                                           | 996-1998 |
+-----------------------------------------------------------+----------+
| UCLA Neiburger Award for excellence in the teaching of    | 1997     |
| the atmospheric sciences                                  |          |
+-----------------------------------------------------------+----------+
| American Association for Aerosol Research, American       | since    |
| Geophysical Union                                         | 1997     |
+-----------------------------------------------------------+----------+

# SUMMARY OF BIBLIOGRAPHY (selection is appended)

8 peer-reviewed (6 senior-authored + 2 junior-authored), + 4 submitted
junior-authored journal articles. 21 senior-authored (33 total)
conference presentations.

# BIBLIOGRAPHY (Selection) 

Russell, P.B., J. Redemann, et al., Comparison of aerosol single
scattering albedos derived by diverse techniques in two North Atlantic
experiments, *J. Atmos. Sci.,* *59*, 609-619, 2002.

Redemann, J., P.B. Russell, and P. Hamill, Dependence of aerosol light
absorption and single scattering albedo on ambient relative humidity for
sulfate aerosols with black carbon cores, *J. Geophys. Res.*, *106*,
27,485-27,495, 2001.

Redemann, J., et al., 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, *J. Geophys. Res.* ,
*105*, 9949-9970, 2000.

Redemann, J., et al., Case studies of the vertical structure of the
direct shortwave aerosol radiative forcing during TARFOX, *J. Geophys.
Res., 105,* 9971-9979, 2000.

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., 103,* 23,287 - 23,298, 1998.

**(e) Robert W. Bergstrom**

### Abbreviated Currriculum Vitae

Bay Area Environmental Research Institute

560 Third Street West, Sonoma, CA 95476

**Education:**

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).

**Professional Experience:**

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). Co-Founder Legisoft (Software Company,
1984-1992). 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. Principal Investigator on
several Cooperative Agreements with NASA Ames Research Center.

# Selected Recent Publications

Bergstrom, R.W., P. Pilewskie, B. Schmid, P.B. Russell, Comparision of
measured and predicted aerosol radiative effects during SAFARI 2000,
accepted, *J. Geophys. Res.,* 2002.

Bergstrom, R. W., P. B. Russell, and P. Hignett, Wavelength dependence
of the absorption of black carbon particles: Predictions and results
from the TARFOX experiment and implications for the aerosol single
scattering albedo, *J. Atmos. Sci., 59,* 568-578, 2002.

Pilewskie, P. et al. (including R.W. Bergstrom), The Discrepancy between
measured and modeled downwelling solar irradiance at the ground:
Dependence on water vapor. *Geophys. Res. Lett., 25*, 137-14, 2000.

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

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.

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.

**5. CURRENT AND PENDING SUPPORT**

**5.1 Lead Principal Investigator, P. Russell**

+---------------+--------------+---------+-----------+-------+-------+
| **Short       | *            | **      | *         | **    | **Sta |
| Title**       | *Agency/Task | Investi | *Dollar** | Durat | tus** |
|               | No.**        | gator** |           | ion** |       |
|               |              |         | **Value** |       |       |
|               |              | *       |           |       |       |
|               |              | *Months |           |       |       |
|               |              | per     |           |       |       |
|               |              | Year**  |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+
| Global        | NASA RTOP    | 3       | \$175,000 | 10/1  | F     |
| Aerosol       |              |         | in FY02   | 998-9 | unded |
| Climatology   | 622-44-75-10 |         |           | /2002 |       |
| (GACP)        |              |         |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+
| ACE-2 &       | NOAA         | 2       | \$151,000 | 5/2   | F     |
| ACE-Asia      | Interagency  |         | in FY02   | 000-4 | unded |
| Aerosol       | Transfer of  |         |           | /2003 |       |
| Radiative     | Funds        |         |           |       |       |
| Effect        | N            |         |           |       |       |
| Studies       | A02AANRG0129 |         |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+
| Solar         | Office of    | 1       | \$58,000  | 11/2  | F     |
| Spectral Flux | Naval        |         | in FY02   | 000-9 | unded |
| & Optical     | Research     |         |           | /2002 |       |
| Depth in      | Award        |         |           |       |       |
| ACE-Asia      | N            |         |           |       |       |
|               | 0001401F0183 |         |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+
| Composite     | NASA RTOP    | 1       | \$20,000  | 10/1  | Fu    |
| Data Analyses |              |         | in FY02   | 995-9 | nded. |
| for Pinatubo  | 621-45-51-10 |         |           | /2002 | FY03  |
| Volcanic      |              |         |           |       | re    |
| Aerosols for  |              |         |           |       | newal |
| SAGE II       |              |         |           |       | pro   |
|               |              |         |           |       | posed |
+---------------+--------------+---------+-----------+-------+-------+
| SAGE III      | NASA RTOP    | 1       | \$105,000 | 11/1  | Fu    |
| Science Team  |              |         | in FY02   | 990-9 | nded. |
|               | 229-10-32-00 |         |           | /2000 | FY    |
|               |              |         |           |       | 03-05 |
|               |              |         |           |       | re    |
|               |              |         |           |       | newal |
|               |              |         |           |       | pro   |
|               |              |         |           |       | posed |
+---------------+--------------+---------+-----------+-------+-------+
| Satellite-    | NASA RTOP    | 4       | \$236,000 | 2/20  | F     |
| Sunphotometer |              |         | in FY02   | 00-12 | unded |
| Studies of    | 291-01-91-45 |         |           | /2002 |       |
| Aerosol,...   |              |         |           |       |       |
+---------------+--------------+---------+-----------+-------+-------+

**5.2 Co-PIs and Co-I**

+---------------+---------------+----+-------+-------+--------+--------+
| **Short       | **Agency/Task | *  | *     |       |        |        |
| Title**       | No.\***       | *E | *Inve |       |        |        |
|               |               | nd | stiga |       |        |        |
|               |               | Da | tor-M |       |        |        |
|               |               | te | onths |       |        |        |
|               |               | ** | per   |       |        |        |
|               |               |    | Year/ |       |        |        |
|               |               |    | Level |       |        |        |
|               |               |    | of    |       |        |        |
|               |               |    | Eff   |       |        |        |
|               |               |    | ort** |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
|               |               |    | P.    | B.    | J.     | R.     |
|               |               |    |       |       |        |        |
|               |               |    | Pile  | S     | Re     | Ber    |
|               |               |    | wskie | chmid | demann | gstrom |
+---------------+---------------+----+-------+-------+--------+--------+
| Global        | NASA RTOPs    | 9/ | 5/42% | 3/25% | 3/25%  | 4/33%  |
| Aerosol       |               | 02 |       |       |        |        |
| Climatology   | 622-44-75-10, |    |       |       |        |        |
| (GACP, 2      |               |    |       |       |        |        |
| tasks,        | 622-44-76-10  |    |       |       |        |        |
| Russell,      |               |    |       |       |        |        |
| Pilewskie PI  |               |    |       |       |        |        |
| of 1 task     |               |    |       |       |        |        |
| each)         |               |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| Solar         | NASA RTOP     | 9/ | 6/50% |       |        |        |
| Spectral      |               | 02 |       |       |        |        |
| Irradiance in | 622-44-76-10  |    |       |       |        |        |
| CRYSTAL       |               |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| Ice-Water     | DOE           | 1  | 1/8%  |       |        |        |
| Content Using | Solicitation  | 2/ |       |       |        |        |
| Near-IR       | 99-16, NASA   | 02 |       |       |        |        |
|               | RTOP          |    |       |       |        |        |
|               | 62            |    |       |       |        |        |
|               | 2-43-00-56-33 |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| ACE-2 and     | NOAA          | 4/ |       | 2/17% | 2/17%  | 3/25%  |
| ACE-Asia      | Interagency   | 03 |       |       |        |        |
| Aerosol       | Transfer of   |    |       |       |        |        |
| Radiative     | Funds         |    |       |       |        |        |
| Effect        | NA02AANRG0129 |    |       |       |        |        |
| Studies       |               |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| Solar         | Office of     | 9/ |       | 1/8%  |        |        |
| Spectral Flux | Naval         | 02 |       |       |        |        |
| & Optical     | Research      |    |       |       |        |        |
| Depth         | Award         |    |       |       |        |        |
| Measurements  | N0001401F0183 |    |       |       |        |        |
| & Analyses in |               |    |       |       |        |        |
| ACE-Asia      |               |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| SAGE III      | NASA RTOP     | 9/ |       | 2/17% | 1/8%   |        |
| Science Team  |               | 02 |       |       |        |        |
|               | 229-10-32-00  |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+
| Satellite-    | NASA RTOP     | 1  |       | 4/33% | 6/50%  | 3/25%  |
| Sunphotometer |               | 2/ |       |       |        |        |
| Studies of    | 291-01-91-45  | 02 |       |       |        |        |
| Aerosol,      |               |    |       |       |        |        |
| Water Vapor   |               |    |       |       |        |        |
| and Ozone     |               |    |       |       |        |        |
+---------------+---------------+----+-------+-------+--------+--------+