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Proposal GC03-086 to the National Oceanic and Atmospheric AdministrationOffice of Global Programs

1100 Wayne Avenue, Suite 1210, Silver Spring, MD 20910-5603Program Element: Aerosol-Climate Interactions Program (ACIP)

Attn: Dr. Joel Levy, 301-427-2089 x111, [email protected]

Quantification of aerosol radiative effects by integrated analyses ofairborne measurements, satellite retrievals, and radiative transfer models

Lead Principal Investigator:

Philip B. Russell Date

Research Scientist, Atmospheric Chemistry and Dynamics BranchEarth Science Division

NASA Ames Research Center, Moffett Field, CA 94035-1000Telephone: 650-604-5404. Fax: 650-604-6779

[email protected]

Co-Principal Investigators:

Prong A: Peter Pilewskie, NASA Ames Research Center (Tel. 650-604- 0746,[email protected])

Prong B: Beat Schmid, Bay Area Environmental Research Institute (Tel. 650-604-5933,[email protected])

Prong C: Jens Redemann, Bay Area Environmental Research Institute (Tel. 650-604-6259,[email protected])

Institutional Representative:

David Peterson DateActing Chief, Earth Science Division

NASA Ames Research CenterTelephone: 650-604-5899. Fax: 650-604-3625

[email protected]

Budget requested from NOAA ($K):Period Prong A

AerosolAbsorption

UsingFlux

Divergence

Prong BExtinctionClosure,

IncludingSatellite

Validation

Prong CRegionalForcingUsing

Satellite andSuborbital

Total

March 1, 2003 - February 28, 2004 00.0 000.0 00.0 00.0March 1, 2004 - February 28, 2005 00.0 000.0 00.0 00.0March 1, 2005 - February 28, 2006 00.0 000.0 00.0 00.0

Three Year Total 00.0 000.0 00.0 00.0

NOAA_ACIPProp020703d.doc ii 3:25 PM,7/3/02

TABLE OF CONTENTS

LIST OF ACRONYMS ii

ABSTRACT 1

1. RESULTS FROM PRIOR RESEARCH 2

2. PROPOSED RESEARCH(STATEMENT OF WORK) 42.1 Problem Identification, Overall

Objectives, Relevance, andMethodology 4

2.2 Prong A. Aerosol Absorption UsingFlux Divergence 6

2.3 Prong B. Extinction Closure,Including Satellite Validation 10

2.4 Prong C. Regional Forcing UsingSatellite and Suborbital Results 14

2.5. Proposed Tasks and Timetable 162.6. 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 AirborneTracking Sunphotometer

ACE Aerosol CharacterizationExperiment

ACIP Aerosol-Climate InteractionsProgram

AERONET Aerosol Robotic NetworkAOD Aerosol Optical DepthARM Atmospheric Radiation

MeasurementARESE ARM Enhanced Shortwave

ExperimentATSR Along Track Scanning RadiometerAVHRR Advanced Very High Resolution

RadiometerCCRI Climate Change Research

InitiativeCERES Clouds and the Earth’s Radiant

Energy SystemCFORS Chemical Weather FORecasting

SystemCIRPAS Center for Interdisciplinary

Remotely Piloted AircraftStudies

CRD Cavity Ring-DownCRYSTAL-FACE

Cirrus Regional Study of TropicalAnvils and Cirrus Layers -Florida Area Cirrus Experiment

CTM Chemical Transport ModelCW Continuous WaveCWV Column Water VaporDISORT DIScrete Ordinates Radiative

TransferDOE Department of EnergyEOS Earth Observing SystemESA European Space AgencyGMS Geostationary Meteorological

SatelliteGOCART Global Ozone Chemistry Aerosol

Radiation TransportGOES Geostationary Operational

Environmental SatelliteINDOEX Indian Ocean ExperimentIOP Intensive Observation PeriodJOSS Joint Office for Scientific StudiesMATCH Model of Atmospheric Transport

and CHemistryMISR Multi-angle Imaging Spectro-

RadiometerMODIS Moderate-resolution Imaging

SpectroradiometerNAAPS Navy Aerosol Analysis and

Prediction SystemNACIP National Aerosol-Climate

Interactions ProgramNAS National Academy of SciencesNIR Near Infra-RedONR Office of Naval ResearchPRIDE Puerto RIco Dust ExperimentSAFARI Southern African Regional

Science InitiativeSeaWiFS Sea-viewing Wide-Field-of-view

SensorSGP Southern Great PlainsSSA Single Scattering AlbedoSSFR Solar Spectral Flux RadiometerTARFOX Tropospheric Aerosol Radiative

Forcing ObservationalExperiment

TOMS Total Ozone MappingSpectrometer

UCAR University Corporation forAtmospheric Research

NOAA_ACIPProp020703d.doc 1 3:25 PM 7/3/02


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 InstituteJens Redemann, Bay Area Environmental Research Institute

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

Abstract. Aerosols are potentially importantagents of climate change, but their impacts oncurrent and future climate are very uncertain.Three prominent reasons for this uncertaintyare: (1) Aerosol effects on radiative fluxes,clouds and hydrology are critically dependenton light absorption by aerosols as a function ofwavelength and aerosol type; however, thisabsorption is currently uncertain, becauseaerosols are highly variable, differentmeasurement techniques often disagree, andsome techniques can change the ambientaerosol. (2) Aerosol effects are equallydependent on the distribution of extinction(solar beam attenuation) in space, time, andwavelength, but extinction derived from in situmeasurements and other techniques (includingsatellite retrievals) often disagrees withmeasured solar beam attenuation. (3) Satelliteshave great potential to reduce uncertainties inaerosol effects, but limitations or uncertaintiesin satellite results require supplementing and/orvalidating them with other information.

We propose integrated analyses to address theabove three problems in a coordinated manner.Our objectives are to: (A) Advance thetechnique of determining wavelength-dependentaerosol absorption using radiative fluxdivergence by comparing flux-divergenceresults for a variety of aerosols to results fromother techniques and applying the flux-divergence technique to climatically significantaerosols. (B) Assess the consistency (closure)between solar beam attenuation measured byairborne sunphotometer and derived from insitu, lidar, and satellite methods. (C) Assessregional aerosol radiative forcing by combiningsatellite and suborbital inputs in state-of-the-artradiative transfer models.

We will analyze data sets from fieldexperiments in which vertically resolved

measurements of radiative flux, solar beamattenuation, and aerosol physical-chemical-optical properties are coordinated with satellitemeasurements of Earth-atmosphere reflectedradiation. The data sets are from ACE-Asia(Spring 2001) and the planned DOE SGPAerosol IOP (May 2003; see list of acronyms onp. ii). We will attack the above problems usingthree highly coordinated prongs, each led by aCo-PI and focused on one of the aboveobjectives. Prong A (Aerosol Absorption UsingFlux Divergence) will use measurements bySolar Spectral Flux Radiometers (SSFRs) toobtain wavelength-dependent aerosol absorptionand will combine absorption withsimultaneously measured optical depths from anAmes Airborne Tracking Sunphotometer(AATS) to obtain wavelength-dependent single-scattering albedo (SSA). Results from ACE-Asia and SGP Aerosol IOP data sets will becompared to simultaneous measurements ofabsorption and SSA by other techniques. ProngB (Extinction Closure) will compare extinctionfrom (i) AATS-measured solar beamattenuation, (ii) in situ physical-chemical-opticalmeasurements on the same aircraft, (iii) lidarand (iv) various satellites. Prong C (RegionalForcing Assessments by Combining Satelliteand Suborbital Results) will use advancedsatellite data sets and address one of the world’smost climatically significant aerosols—theAsian Pacific plume of mineral dust, soot,organics, sulfates, and sea salt.

The proposed research will benefit the generalpublic and the scientific community by reducingthe uncertainties about aerosol effects onclimate cited by the National Academy ofSciences (NAS) analysis of key questions inclimate change science and by the White Paperof the National Aerosol-Climate InteractionsProgram (NACIP).



1. RESULTS FROM PRIOR RESEARCH

As required by the Instructions for SubmittingProposals (http://www.ogp.noaa.gov/c&gc/ao/2003/propinstruction.htm), this sect ionsummarizes, in two pages, results of eachrelevant research project during the last 3years. More extensive descriptions of selectedresults and their relevance to the proposedresearch are given in Sections 2.2-2.4.

ACE-2 and ACE-Asia Aerosol RadiativeEffect Studies Using AirborneSunphotometer, Satellite and In-SituM e a s u r e m e n t s . N O A A AwardNA02AANRG0129, NASA RTOP 622-96-00-57-01, 5/2000-4/2003, $466,100. This awardsupported (a) Acquisition and use of satellitedata to plan ACE-Asia approaches, includingselection of areas most favorable to measuringaerosol radiative effects with least interferenceby clouds; (b) Preliminary optical modeling ofthe complex aerosols expected in ACE-Asia,by building on models developed for sulfate,carbonaceous, and mineral dust aerosolsstudied in TARFOX, ACE-2, and PRIDE; (c)Comparison of aerosol absorption derived byflux-change and other techniques in TARFOXand ACE-2; (d) Contributions to the Scienceand Implementation Plan for ACE-Asia 2001;(e) Development and testing of sunphotometricwater vapor analysis techniques for ACE-Asia;(f) Mission Scientist duties for ACE-Asia C-130 flights addressing aerosol-radiationinteractions; (g) Calibrations, integration, testflights, and measurements using the 6-channelAmes Airborne Tracking Sunphotometer(AATS-6) on the C-130 in ACE-Asia Spring2001; (h) Intercomparisons, validations, andclosure analyses combining the AATS-6 datawith satellite and other suborbital data; and (i)Aerosol radiative effect calculations thatcombine satellite and suborbital inputs. Resultsare described in four journal publications ledby our team (Redemann et al., 2001a;Bergstrom et al., 2002a; Russell et al., 2002;Schmid et al., 2001), plus several others wecoauthored (e.g., Ingold et al., 2000; Kiedron etal., 2000; Revercomb et al., 2001; Wang et al.,2002a). Our AATS-6 ACE-Asia data set hasbeen 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 fromUCAR-JOSS. These data are being used inmany ongoing studies that have been reportedat numerous conferences (e.g., Chin et al.,2001; Livingston et al., 2001; Redemann et al.,2001b,c; Russell et al., 2001a,b; Kuzmanoski etal., 2002). Selected results are summarized inSections 2.2-2.4 of this proposal.

Solar Spectral Flux, Optical Depth, WaterVapor, and Ozone Measurements andAnalyses in the ACE-Asia Spring 2001Intensive Experiment. Office of NavalResearch Award N0001401F0183, NASARTOP 622-96-00-56-79, 11/2000-9/2002,$163,900. This award supported measurementsand analyses of solar spectral fluxes and directbeam transmissions in support of the ACE-Asia Spring 2001 Intensive Experiment.Spectral fluxes (300-1700 nm at 10 nmresolution) were measured by zenith and nadirviewing Solar Spectral Flux Radiometers(SSFRs) on the CIRPAS Twin Otter.Simultaneously and on the same aircraft, directbeam transmissions were measured in 14narrow bands (354-1558 nm) by AATS-14.The AATS-measured beam transmissions wereanalyzed to derive aerosol and thin-cloudoptical depth at 13 wavelengths, plus columnwater vapor overburden. The data were used tosupport the overall goals of ACE-Asia, withemphasis on determining the net solar radiativeforcing of East Asian/West Pacific aerosols,quantifying the solar spectral radiative energybudget in the presence of elevated aerosolloading, supporting satellite algorithmvalidation, and providing tests of closure within situ measurements. Our AATS-14 ACE-Asia data set has been archived and madeavailable to the user community (see above forlink). Results are described in Wang et al.(2002a), in numerous ACE-Asia conferencepresentations, and in many papers beingdrafted for the ACE-Asia special issue of J.Geophys. Res. Selected results are shown inSections 2.2-2.4.

Improved Exploitation of Field Data Sets toAddress Aerosol Radiative-Climatic Effects


and Development of a Global AerosolClimatology. NASA RTOP 622-44-75-10,10/98-9/02, $675,000. This award supportedtasks on (a) Airborne sunphotometer opticaldepth data quality checks, (b) Mixed aerosoloptical modeling, (c) Automated sizedistribution retrievals, (d) Size distributioncomparisons and closure studies, (e) Watervapor/aerosol interactions and satelliteretrievals, and (f) Flux change/radiative forcingstudies. These tasks were accomplishedprimarily by analyses of data sets fromTARFOX and ACE-2. Results are described in10 journal publications led by the Amessunphotometer-satellite team (Bergstrom andRussell, 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 etal., 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. N A S ARTOP 291-01-91-45, 2/1999-12/2002,$675,000. This award supported modeling andintegrated analyses of suborbital and satellitedata to address impacts of biomass smokes,Asian and African soil dust, and othertropospheric aerosols and water vapor on theEarth’s radiation budget. Research focusedprimarily on analysis of data from threeinternational multiplatform field campaigns:PRIDE, SAFARI 2000, and ACE Asia. Datafrom airborne sunphotometers and otherairborne and surface remote and in situmeasurements were combined in closurestudies to test and improve models of complexmulticomponent tropospheric aerosols and theirinteractions with water vapor and radiation.Pre-campaign modeling and algorithmdevelopment focused on providing realtimeanalysis and display capabilities useful forstudies of aerosol evolution and mass budgets,including flight planning and direction. Duringand after campaigns suborbital data and modelswere used to validate satellite measurements ofaerosols and water vapor. They were then usedto supplement the satellite data with otherinformation needed for studies of aerosolphysicochemical evolution and radiative-climatic effects. In particular, satellite maps ofaerosol properties were combined withsuborbital data in radiative transfer models to

assess aerosol effects on radiation balance andheating 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; Levyet 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 andVariability of the Direct Spectral RadiativeForcing by Atmospheric Aerosols. NASARTOP 622-44-76-10, 10/1998-9/2002,$348,000. This award supported the analysis ofhyperspectral solar flux measurements fromvarious flight missions to determine the directradiative forcing by aerosols. Three journalmanuscripts were submitted, describing resultsfrom PRIDE and SAFARI 2000 (Bergstrom etal., 2002b; Pilewskie et al., 2002a,c). Selectedresults are summarized in Section 2.2.

Retrieval of Ice-Water Content Using Near-Infrared Remote Sensing. DOE AtmosphericRadiation Measurement Program, SolicitationNotice 99-16, NASA RTOP 622-43-00-56-33,10/1999-9/2002, $230,000. This awardsupported the use Solar Spectral FluxRadiometer (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 fluxspectra measured above and below cloud canbe used to derive cloud optical and physicalproperties which are in agreement with in situmicrophysical measurements. See also Section2.2.4.

Measurement of Solar Spectral Irradiancein Support of CRYSTAL. NASA RTOP 622-44-76-10, 10/2001-9/2002, $437,000. Thisaward supported measurements by SolarSpectral Flux Radiometers (SSFRs) andbroadband infrared radiometers on two aircraft(ER-2 and Twin Otter) in the Cirrus RegionalStudy of Tropical Anvils and Cirrus Layers -Florida Area Cirrus Experiment (CRYSTAL-FACE, July 2002), including sensorpreparation, modification, calibration,integration, flight operation, and initial datareduction. Complete data analysis,presentation, and publication are planned forFY 2003-2004.


2. PROPOSED RESEARCH(STATEMENT OF WORK)

2.1 Problem Identification, OverallObjectives, Relevance, and Methodology

Aerosol effects on atmospheric radiation posemajor uncertainties in understanding past andpresent climates and in predicting the futureclimate. These uncertainties, and strategies forreducing them, have recently been emphasizedby the National Academy of Sciences’ analysisof key questions in climate change science(NAS, 2001). Recent experiments designed toreduce these uncertainties (e.g., TARFOX,ACE-2, INDOEX, PRIDE, SAFARI-2000,ACE-Asia) have produced important advancesbut in the process have posed remainingquestions that must be answered (Russell et al.,1999a; Raes et al., 2000; Russell andHeintzenberg, 2000; Ramanathan et al., 2001,2002; Levy, 2002c). These remainingquestions have guided the research prioritiesand strategies articulated by the NationalAerosol-Climate Interaction Program (NACIP)and in turn by NOAA’s Aerosol-ClimateInteractions Program (ACIP). For example,NACIP and ACIP (Ramanathan et al., 2002;Levy, 2002a,b) emphasize the importance ofabsorbing aerosol components (including blackand organic carbon and mineral dust) both indirectly affecting Earth-atmosphere radiationbudgets and in determining aerosol-cloudinteractions and regional hydrology. Aerosolabsorption deposits solar energy that wouldhave warmed Earth’s surface into atmosphericlayers aloft. There it can shorten cloudlifetimes by causing them to “burn off”(Ackerman et al., 2000). Absorbing aerosolscan also inhibit cloud formation in severalways. The reduction in surface heatingdecreases evapotranspiration, and thecombination of increased heating aloft andreduced heating below weakens the convectivemotions that drive much cloud formation.Thus aerosol absorption can affect regionalhydrology in addition to radiative forcing.Quantifying these effects requires aquantitative description of the vertical,regional, and temporal distributions of aerosolabsorption across all wavelengths whereabsorbed energy is significant.

In its White Paper (Ramanathan et al., 2002)NACIP also emphasizes the need to quantifyaerosol properties and effects on a region-by-region basis and to represent these propertiesand effects accurately in models that calculate

aerosol radiative and climatic effects. The“new paradigm” of NACIP is to attack theaerosol-climate forcing problem from anobservational basis. NACIP stresses that asound observational basis requires combiningsatellite observations (the only mode for globalobservations of aerosols) with multi-platformmeasurements at the surface and within theatmosphere, including aircraft flights to mapthe vertical and horizontal variations of keyaerosol properties and effects. NACIP alsostresses the need to both quantify and reducethe uncertainties in both observations andmodel calculations.

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

1. Investigations that address limiting factorsin current in-situ measurement capabilitiesby using methods or instruments capable ofautonomous operation on light aircraft.Prime examples are methods to measureae roso l l i gh t abso rp t ion andintercomparisons of different instruments.

2. Spin-up of comprehensive light aircraft fieldmeasurements of the most radiativelyimportant aerosols, highly integrated withstate-of-the-art modeling.

3. Analyses of ACE-Asia data that stresssynergistic use of multi-disciplinary datasets, with emphasis on achieving closure onthe radiative impacts of Asian aerosolsobserved during the campaign.

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

A . Advance the technique of determiningwavelength-dependent aerosol absorptionusing radiative flux divergence bycomparing flux-divergence results for avariety of aerosols to results from othertechniques and applying the flux-divergencetechnique to climatically significantaerosols.

B . Assess the consistency (closure) betweensolar beam attenuation measured by airbornesunphotometer and derived from in situ,lidar, and satellite methods.


C. Assess regional aerosol radiative forcing bycombining satellite and suborbital inputs instate-of-the-art radiative transfer models.

Our proposed approach is to analyze data setsfrom field experiments in which vertically andhorizontally resolved measurements ofradiative flux, solar beam attenuation, andaerosol physical-chemical-optical propertiesare coordinated with satellite measurements ofEarth-atmosphere reflected radiation. The datasets, from ACE-Asia (Spring 2001) and theplanned DOE SGP Aerosol IOP (May 2003)are described more fully below. First wedescribe how the work would be organized andthe methods employed.

We plan to attack the above problems usingthree highly coordinated prongs, each led by aCo-PI (as listed on the cover page) and focusedon one of the above objectives.

Prong A. Aerosol Absorption Using FluxDivergence. Radiative flux is the flow ofradiant energy (diffuse plus direct) across asurface. The net (downwelling minusupwelling) flux at the top of a layer minus thenet flux at the bottom (i.e., the net fluxdivergence across a layer) is the energyabsorbed by the layer. Hence, flux divergencemeasurements are a direct way of determiningthe absorption by whatever is in anatmospheric layer, in its ambient state.Measuring flux divergence with fine spectralresolution allows the identification andsubtraction of gas absorption features, thusisolating the aerosol absorption. Perturbation orloss of aerosol particles by aircraft andinstrument inlet and filter effects is avoided. Asshown in Section 2.2, early publications fromPRIDE and SAFARI illustrate how Dr.Pilewskie’s Solar Spectral Flux Radiometers(SSFRs) yield wavelength-dependent aerosolabsorption, which, when combined with opticaldepths from an Ames Airborne TrackingSunphotometer (AATS) in a radiative transfermodel, yields wavelength-dependent single-scattering albedo (SSA). These techniques willbe applied to the ACE-Asia and SGP AerosolIOP data sets, and the results compared tosimultaneous measurements of absorption andSSA by other techniques.

Prong B. Extinction Closure, IncludingSatellite Validation. An important class ofextinction closure studies addresses thequestion: "Can in situ measurements of aerosolproperties account for the solar beamattenuation (extinction) by an aerosol layer orcolumn?" Measuring solar beam attenuationby an AATS on the same aircraft as in situsensors allows an exact match in the aerosollayers described by the attenuation and in situmeasurements. Such a match allows the best-defined comparison between attenuation and insitu results. As shown in Section 2.3, suchcomparisons have revealed important insightsabout aerosol sampling and inadvertentmodification in such previous experiments asTARFOX, ACE-2, and SAFARI. We will basethe proposed study of extinction closure on theACE-Asia and SGP Aerosol IOP data sets. Inaddition to comparisons to airborne in situmeasurements we will include comparisons tolidar extinction profiles and total columnaerosol optical depth (AOD) from varioussatellites and models (see Section 2.3).

Prong C. Regional Forcing Assessments byCombining Satellite and Suborbital Results.As amplified in Section 2.4, this prong will usethe general approach we applied to NorthAtlantic aerosols (Bergstrom and Russell,1999), but will extend it in many ways: byusing more advanced satellite and suborbitaldata sets and by applying it to the Asian-Pacificaerosol. This aerosol is one of the world’smost climatically significant because of itsgreat concentration, extent, and expectedgrowth (e.g., Huebert et al., 1999). It is alsoone of the most difficult to assess, because it isa complicated and varying mixture of manycomponents, including desert dust, a strongsoot component, organics, sulfates, and seasalt.

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

Data Set 1. ACE-Asia (Spring 2001). This setincludes measurements on the Twin Otteraircraft by SSFRs, AATS-14, and many in situsensors, plus measurements on the C-130aircraft by AATS-6 and many other sensors, allmade in coordination with satellite overpasses.The satellite data products includemultiwavelength aerosol optical depth (AOD)


from sensors such as MISR, MODIS,SeaWiFS, AVHRR, and others. Also useful inthe analyses will be the fields of AOD andother properties predicted by the chemical-transport models (CTMs) CFORS, GOCART,MATCH, and NAAPS (see list of acronyms onp. iii; see Section 2.3 for references describingmodels). The ACE-Asia campaign ended about1 year ago, and early presentations (e.g.,Redemann et al., 2001b,c) and journalmanuscripts (e.g., Wang et al., 2002a) havedemonstrated the outstanding quality and scopeof the data set. However, our current ACE-Asia analysis funding will end within a yearand will not cover the highly integratedanalyses proposed here. The ACE-Asia data setprovides a golden opportunity to extend theabovementioned PRIDE and SAFARI fluxdivergence analyses to one of the world’s mostclimatically significant aerosols—the AsianPacific plume of desert dust and pollution.

In addition to the satellite sensors mentionedabove, we plan to contribute to the validationof CERES data by furnishing ACE-AsiaAATS-6 and -14 data, and data-use advice, toDr. Sundar Christopher of the University ofAlabama in Huntsville. Dr. Christopher isproposing to NOAA ACIP an investigation thatwould, among other things, use biaxial scanmode CERES data to develop angular modelsfor estimating radiative fluxes and therebyreduce uncertainties in aerosol radiativeforcing.

Data Set 2. DOE SGP Aerosol IOP (May2003). Plans for this experiment, whichrecently received tentative approval from theARM Science Team Executive Committee,include measurements by SSFR, AATS-14,and many others. A significant advance will bemounting the up-looking SSFR on a stableplatform, which will reduce tilt effects andthereby extend the SSFR absorption analysesto smaller aerosol optical depths. This willextend the range of aerosol conditions to whichthe flux divergence technique can be applied.Dr. Beat Schmid (Co-PI) has been involved inthe planning of the May 2003 IOP and hasdeveloped an airborne payload based on theCIRPAS Twin Otter aircraft.

2.2 Prong A. Aerosol Absorption Using FluxDivergence

The goals of this prong of the proposedresearch are to:

• Advance the technique of determiningwavelength-dependent aerosol absorptionusing radiative flux divergence, bycomparing flux-divergence results for avariety of aerosols to results from othertechniques and applying the flux-divergencetechnique to climatically significant aerosols.

• Provide results on wavelength-dependentabsorption and SSA of significant aerosoltypes to Prongs B and C and to thecommunity via summary data files,presentations and publications.

Several recent airborne intensive fieldcampaigns conducted to study the radiativeforcing of clouds and various types of aerosolshave included the measurement of solarspectral irradiance over flight profilesthroughout the troposphere and lowerstratosphere. These data provided the means todetermine the net spectral flux at variousatmospheric levels, from which spectral fluxdivergence and absorption were derived.Further analysis through radiative transfermodeling has been applied to derive aerosol orcloud droplet single scattering albedo. Theinitial successes of these measurements andanalyses provide the basis for expanding ourefforts toward the objectives described in thisproposal. In this section we describe themeasurement and modeling tools used andpresent some of our results from recent fieldstudies.

2.2.1 The Solar Spectral Flux Radiometer

The Solar Spectral Flux Radiometer (SSFR) isa moderate resolution flux (irradiance)spectrometer covering the wavelength range300-1700 nm. The SSFR uses an identical pairof Zeiss Monolithic Miniature SpectrometerModules (MMS-1 and MMS-NIR) forsimultaneous zenith and nadir viewing. TheMMS-1 has a flat-field, 366 mm-1 grating and aHamamatsu Si linear diode array detector. Wecontrol the MMS-1 module temperature to27±0.3º C. The MMS-NIR has a 179 mm-1 flat-


field grating with a 128-element InGaAs lineardiode array, thermoelectrically cooled to 0º C.Spectral resolution is 9 nm for the MMS-1 and12 nm for the MMS-NIR. The light collector isa scaled version of the optical collectordesigned by Crowther (1998). Tests of thedesign show a high degree of linearity withcosine of incidence angle to values as low as0.1. A water-free quartz hyperdome protectsthe light collector in flight. A high-gradecustom-made fiber optic bundle transmitsincident light to the two spectrometer inputslits. Data acquisition and control use a 226MHz 586 PC. Dynamic resolution is 15 bitsfull range; sampling resolution is ~3.25 nm.Spectral sampling is at ~1 Hz. Data is recordedon a 220 Mbyte PCMCIA flash memory card.

The SSFR is calibrated for wavelength, angularresponse, and absolute spectral power. Spectralcalibration is referenced to the HeNe laser lineat 632.8 nm, a temperature stabilized laserdiode line at 1298 nm, and several lines fromHg, Xe, and Ar lamps. Spectral powercalibration uses a NIST secondary standardlamp and a LI-COR Field Calibrator. The LI-COR units are fully enclosed devices suitablefor field use. In the field we calibrate the SSFRbefore and after flights using the same portableLI-COR devices to monitor SSFR stabilityduring the experiment.

Over most of the active spectral range theshort-term stability, or precision, is


Science Initiative (SAFARI 2000), affordingthe opportunity to apply the flux divergencetechnique to the biomass burning aerosols thatprevailed in that study. Figure 1 shows resultsfrom the 6 September flight, which includedtwo stacked level legs over Mongu, Zambia,during an intense haze episode. SSFRdownwelling and upwelling irradiance (flux)spectra are shown in Figure 1a; albedo spectra(ratios of upwelling to downwelling flux) are inFigure 1b, and aerosol optical depths measuredsimultaneously by AATS-14 from the sameaircraft are in Figure 1c. Note that the near-infrared albedo aloft (575 mb) is less than thatnear the surface (878 mb), suggesting verystrong absolute absorption by the massiveoptically thick haze layer present between thesetwo heights. Figure 2a shows the spectralabsorption for this layer. The solid curve istotal absorption; by interpolating across thevarious near-infrared gas absorption bands weestimate the aerosol contribution to theabsorption as depicted by the dashed curve.

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Figure 1. (a) Upwelling and downwelling fluxspectra from two SAFARI Convair-580 flightlegs on 6 September 2000. (b) Albedo spectrafrom the same legs. (c) Corresponding aerosoloptical depths from AATS-14 measurements.

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Figure 2. (a) Spectral flux divergence(absorption) between the highest and lowestflight legs in the 6 September flight profileover Mongu, Zambia. The dashed curverepresents the aerosol absorption “continuum.”(b) Fractional absorption from the same case.Red curves indicate the range of uncertainty.

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Figure 4. Measured (blue spectrum) andmodeled (red triangles) fractional absorptionfor a dust layer during the PRIDE case studyon 15 July 2000.

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Figure 5. (a) Measured (blue) and modeled(red) absorption spectra for the ACE-Asiaprofile flown on Twin Otter Flight RF07, 12April 2001. (b) Corresponding spectra offractional absorption. (c) AOD spectrameasured simultaneously on the same aircraft.

The fractional absorption in Figure 2a can becombined with the AOD in Figure 1c toestimate aerosol single scattering albedo usingthe radiative transfer model described above.The best-fit single scattering albedo thusobtained is shown in Figure 3 with thewavelength regions dominated by gaseous

absorption removed. The error bars for thesingle scattering albedo are estimated from theerror bars in the fractional absorption, shown inFigure 2b. These errors result primarily fromuncertainties in SSFR tilt during aircraft pitchand roll (see also below). The spectral slope ofthe aerosol SSA shows the decrease withwavelength expected for black carbon(Bergstrom et al., 2002a).

2.2.3.2 Dust Aerosol. Radiative profiles indust layers were acquired during the PuertoRico Dust Experiment (PRIDE) and the AsianPacific Aerosol Characterization Experiment(ACE-Asia). Following the methodologydescribed above, we used these to derive thespectral absorption in dust layers from whichaerosol radiative parameters could be derived.Figure 4 shows agreement between measuredand modeled dust absorption during PRIDE on15 July 2000.

Figure 5 shows spectra of absorption and AODmeasured simultaneously on an ACE-Asiaflight. The model calculations shown in Figure5 assumed a wavelength-independent SSA,which clearly underestimates absorption forwavelengths


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Figure 7. Derived dust single scattering albedofrom PRIDE (blue curve) and ACE-Asia (greencurve). Five aerosol models are shown forcomparison (Quijano et al., 2000; Ackermanand Cox, 1988)

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

2.2.4 Solar Absorption in Clouds, andRelationship to Aerosols

The NACIP White Paper (Ramanathan et al.,2002) emphasizes the need to elucidate themany aerosol-cloud interactions. As noted inSection 2.1, one such interaction is the“burning off” of clouds by aerosol absorption,and there are others relating to modifiedsurface evapotranspiration and atmosphericdynamics. Hence, there is a need to betterunderstand the relationships between aerosolabsorption and cloud properties. In thisconnection we note that the flux divergencemethod can be used to measure cloudabsorption and other properties as well asaerosol absorption. In fact, SSFRmeasurements have been used for this purposein the second ARM Enhanced ShortwaveExperiment (ARESE II). Recent results(Pilewskie et al., 2002b) show that SSFR fluxspectra measured above and below cloud canbe used to derive cloud absorption, mean

effective droplet radius, cloud optical depth,and cloud water path values that agree with insitu microphysical measurements within therange of instrumental uncertainty. In theproposed research we plan to explore thiscapability by selecting and analyzingappropriate cloud-aerosol cases in the ACE-Asia and SGP Aerosol IOP data sets.

2.3 Prong B. Extinction Closure, IncludingSatellite Validation

The goals of this prong of the proposedresearch are to:

• Assess the consistency (closure) betweensolar beam attenuation measured by airbornesunphotometer and derived from in situ,lidar, and satellite methods.

• Provide results, grouped by aerosolcondition, to Prongs A and C and to thecommunity via summary data files,presentations and publications.

An important class of extinction closure studiesaddresses the question: "Can in situmeasurements of aerosol properties account forthe solar beam attenuation (extinction) by anaerosol layer or column?" Such closure studieshave revealed important insights about aerosolsampling and inadvertent modification in suchprevious experiments as TARFOX (Hegg et al.,1997; Hartley et al. 2000), ACE-2 (Collins etal., 2000, Schmid et al., 2000) and SAFARI2000 (Magi et al., 2002). We will base thestudy of extinction closure on the ACE-Asiaand SGP Aerosol IOP data sets, and willinclude lidar extinction profiles and totalcolumn AOD from various satellites (as donefor SAFARI by Schmid et al., 2002) andmodels (see below).

Key is the measurement of aerosol opticaldepth and columnar water vapor with the AmesAirborne Tracking Sunphotometers, AATS-14and AATS-6 (e.g., Matsumoto et al., 1987).This is because inlet effects (e.g., loss orenhancement of large particles, shrinkage byevaporation of water, organics, or nitrates) andfilter effects are avoided. AATS-14 measuredthe transmission of the direct solar beam at 14


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Figure 8. Left panel: Aerosol optical depth profiles at 13 wavelengths from 354 to 1558 nmcalculated from AATS-14 measurements acquired during an aircraft ascent south of Korea on 17April 2001 during ACE-Asia. Right panel: Corresponding aerosol extinction profiles derived bydifferentiating 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 IOPthe instrument’s wavelength range is currentlybeing extended to 2138 nm. AATS-6 measuresat 6 discrete wavelengths between 380 and1020 nm. From the direct solar beamtransmission measurement we derive spectralaerosol optical depths AOD(λ), columnar watervapor, CWV, and columnar ozone. Flying atdifferent altitudes over a fixed location allowsderivation of AOD(λ) or CWV in a givenlayer. Data obtained in vertical profiles allowsderivation of spectral aerosol extinction Ea(λ)(see Figure ) and water vapor density ρw.

Measuring solar beam attenuation by an AATSon the same aircraft as in situ sensors allows anexact match in the aerosol layers described bythe attenuation and in situ measurements. Sucha match allows the best-defined comparisonbetween attenuation and in situ results. Anexample from ACE-Asia where the in situextinction is computed as the sum of scattering(from humidified nephelometry) and

absorption (PSAP instrument) is shown inFigure 9. Preliminary ACE-Asia resultsobtained from a partial data set from bothairborne platforms (Twin Otter and C-130)indicate that total layer AODs calculated fromthe combination of nephelometer and PSAPdata are 20% - 40% less than those fromAATS-6 or -14 measurements (Redemann etal., 2002). We propose a detailed analysis of allavailable ACE-Asia profiles includingstratification of the closure results with respectto aerosol types, relative humidity, flightpattern during profile and other factors. Figure10 shows an example result from an ACE-Asiaclosure study (Wang et al., 2002) thatcompares aerosol extinction from AATS-14with values calculated from Mie theory usingmeasured size distributions and composition(used to determine the complex refractiveindices). This study, now submitted to J.Geophys Res., is limited to four Twin Ottervertical profiles. We propose to conduct thesame type of analysis for as many C-130 andTwin Otter vertical profiles as possible.


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Figure 9. Aerosol optical depth (left) and extinction (right) profile at 550 nm measured byAATS-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 describedclosure analysis to the data expected from theMay 2003 SGP Aerosol IOP. This IOP willinclude airborne measurements of extinctionusing the relatively new Continuous WaveCavity Ring-Down (CW-CRD) technology(Strawa et al., 2002). Although the CW-CRDinstrument does sample aerosol through aninlet it directly measures in situ extinction,whereas typically in situ extinction is derivedfrom the sum of scattering and absorptionmeasured with two separate instruments(usually nephelometer and filter basedabsorption). Further advantages of the CW-CRD technique are the absence of filterartifacts, no heating of sample, no angulartruncation error, and no illumination errors.

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

During ACE-Asia considerable effort wasdevoted to coordinat ing aircraftmeasurements with satellite overpasses. The

list of sensors includes AVHRR, GMS-5,MISR, MODIS, SeaWiFS, TOMS andA T S R - 2 . Airborne sunphotometermeasurements flown along transects near theland or ocean surface in ACE-Asia provideaerosol optical depth spectra useful forvalidating products from most of thesesensors. At this point we have performedlimited comparisons with SeaWiFS (Figure11) and MISR. These indicate goodagreement between SeaWiFS and AATS-14 ifthe Hsu et al. (2002) algorithm is used. MISRcurrently tends to overestimate the AOD withrespect to AATS-14. Prompted by these earlycomparisons the MISR team became aware ofan instrument stray light problem, which iscurrently being addressed (R. Kahn, personalcommunication). In the framework of thisproposal we hope to complete comparisonswith all sensors listed above.

Finally we propose to use our ACE-AsiaAATS measurements to help validate aerosoltransport models such as CFORS (e.g., Uno etal., 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


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

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


Figure 12. (a) June-August mean AOD at 500 nm derived from AVHRR radiances by Husar etal. (1997). (b) 24h-average, cloud-free direct shortwave aerosol radiative forcing at thetropopause 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 inTARFOX and ACE-2. The choice of SSA shown here, ωa=0.9, is based on radiative fluxmeasurements; other measurements yielded larger SSA (ωa~0.92 to 0.98) (Russell et al., 2002a).Bergstrom and Russell (1999) show results for ωa=1 and ωa=0.9.

Figure 13. (a) April 2001 monthly mean AOD at 865 nm derived from SeaWiFS radiances usingthe algorithm of Hsu et al. (2002). (b) 24h-average, cloud-free direct shortwave aerosol radiativeforcing at the surface in Wm-2, derived from total aerosol optical depth shown in (a). Theradiative calculation assumes an aerosol model of dust over pollution aerosols. The relativeamounts of dust and pollution aerosols are adjusted pixel-by-pixel to force model Angstromexponent to equal the Angstrom exponent derived from the 4-wavelength SeaWiFS radiances byHsu et al. (2002).

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gradients. An initial comparison betweenGOCART and AATS-14 has been presented byChin et al. (2001).

2.4 Prong C. Regional Forcing Assessmentsby Combining Satellite and SuborbitalResults

Our first regional assessment of aerosolradiative forcing (Bergstrom and Russell,1999) combined single-wavelength seasonalAOD maps of the North Atlantic region withaerosol intensive properties derived from theTARFOX and ACE-2 field programs. TheAOD maps were derived by Husar et al. (1997)from AVHRR reflectances; an example isshown in Figure 12a. The aerosol intensiveproperties included optical depth wavelengthdependence across the solar spectrum, singlescattering albedo, hemispheric upscatterfraction, and relative vertical profile, allsynthesized from suborbital measurements byaircraft and ground sites (including lidars). Thesatellite and suborbital inputs were combinedin a radiative transfer model (Bergstrom et al.,2002b) to derive maps of cloud-free and all-skyradiative forcing; an example is shown inFigure 12b.

The goal of Prong C is to provide improvedassessments of regional radiative forcing byextending the approach of Bergstrom andRussell (1999) to include the greatly enhancedmeasurement capabilities of newer satellitesensors (e.g., SeaWiFS, MODIS, MISR,CERES) and new field campaign data. Forexample, the following satellite-derived aerosolproducts are available:

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

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

3 . Maps of absorbing aerosol index fromTOMS (http://toms.gsfc.nasa.gov/aerosols/aerosols.html)

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

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

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

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

A primary focus of Prong C will be the AsianPacific plume of desert dust and pollution,which is one of the world’s most climaticallysignificant aerosols. Initial studies on theradiative impact of Asian aerosols on the basisof SeaWiFS-derived measurements of aerosoloptical depth and Angstrom exponent, as wellas in situ data obtained during ACE-Asia, havebeen presented by Russell et al. (2002b).Figure 13a shows a map of the April 2001monthly mean aerosol optical depth at 865 nm,derived from SeaWiFS-measured radiancesusing the algorithm of Hsu et al. (2002). Usingthe map in Figure 13a in conjunction with thesatellite retrieved Angstrom parameter andassumptions regarding (i) the aerosol singlescattering albedo (and its wavelengthdependence); (ii) the asymmetry parameter(and its wavelength dependence) and (iii) thepartitioning of the relative contributions ofmineral dust and pollution-type aerosol to thetotal aerosol optical depth enables thecomputation of corresponding maps ofshortwave direct aerosol radiative forcing ofclimate at the surface or at the top of theatmosphere (TOA). An example for surfaceradiative forcing is shown in Figure 13b.

In computing the forcing in Figure 13b, wewere limited to taking the SeaWiFS-retrievedoptical depth and Angstrom exponent and thenapplying our own radiative transfer model. Inthis work we propose to utilize the results fromParts A and B above to improve our estimatesof the radiative forcing of aerosols in the ACE-Asia region. In particular, the results of thecolumn 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 ofaerosol absorption properties as measuredby the PSAP instruments aboard the NCARC-130 and the CIRPAS Twin-Otter;

2 . The vertical distribution of aerosolext inct ion from comparison ofsunphotometer- and in situ- derived aerosolproperties (cf. Figures 8-10);


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

This information will be combined with theobserved absorption results of Prong A(Section 2.2) to constrain the inputs to theradiative transfer model. For example, theaerosol observed during the ACE Asiacampaign was extremely complex mixture ofdust and urban pollution. Using the detailedradiative transfer model described in Section2.2.2, we will compute the effect of the multi-modal aerosol on the observed satelliteradiances. (The included multiple scatteringcode, DISORT, can compute radiances as wellas fluxes.)

To avoid the inconsistency in using one modelof aerosol radiative properties to convert thesatellite-measured radiances into aerosoloptical depth and a different model to convertthe aerosol optical depth to aerosol radiativeforcing, we also propose to collaborate with theteams of A. Higurashi (National Institute ofEnvironmental Studies, Ibaraki, Japan) and T.Nakajima (Univ. of Tokyo, Tokyo, Japan). Wewill work with them to develop an aerosolmodel for SeaWiFS measurements that will beused in both the conversion of satelliteradiances to AOD and in the conversion ofAOD to aerosol radiative forcing of climate.We will also perform sensitivity tests to assesshow changing aerosol model parameters affectsderived forcing, both when using the samemodel for both steps, and when using differentmodels in each step. This should enable us tomore accurately estimate the aerosol radiativeforcing and the associated uncertainties. Amajor objective will be to quantify and reducethe uncertainties in aerosol radiative-climaticeffects cited by NACIP (Ramanathan et al.,2002)

Initial comparisons between various satellitesensors (e.g., MODIS vs. SeaWiFS) indicateconsiderable differences in temporally-averaged fields of aerosol optical depth. Suchdifferences could be due to the complexinteraction of aerosols and clouds in thewestern Pacific region and the associatedcomplications in satellite cloud screeningalgorithms, or due to inadequate modeling ofthe mixtures of various aerosol types insatellite retrieval algorithms. Hence, as asecond element of this task, we propose tocompare the aerosol optical depth fields

derived from various satellite sensors (MODIS,SeaWiFS, MISR, AVHRR) as they are relevantto the calculation of regional mean aerosolradiative forcing of climate. Based on thecomparison of instantaneously measuredaerosol optical depth between suborbital andsatellite sensors proposed in Section 2.3, weexpect to aid in explaining any differencesfound between aerosol products from differentsatellite sensors.

2.5 Proposed Tasks and Timetable

For the funding requested in Section 3 we willprovide the necessary personnel, equipment,and facilities, and will perform the followingtasks.

2.5.1 Year One (March 1, 2003 - February28, 2004)

2.5.1.1 Task A1: Derive aerosol absorptionand SSA spectra for a representative variety ofaerosol types and conditions using the ACE-Asia Twin Otter SSFR and AATS-14 data sets.Assess uncertainties, taking into accountradiometer tilt and all other significant errorsources. Compare results to those from otherACE-Asia measurements and the literature forsimilar aerosols. Begin corresponding analysesfor the May 2003 SGP Aerosol IOP data set, tothe extent permitted by the state of datareduction for that experiment.

2.5.1.2 Task A2: Provide results of Task A1 toProngs B and C and to the community insummary data files, presentations andpublications.

2.5.1.3 Task B1: Perform extinction closurestudies for a representative variety of ACE-Asia aerosols by comparing extinction andoptical depth spectra and profiles measured byairborne sunphotometer to results fromairborne in situ, lidar, and satellite methods.Synthesize results in terms of uncertainties inkey parameters as a function of aerosol andsurface condition (e.g., over water vs. land) andmeasurement or retrieval type.

2.5.1.4 Task B2: Provide results of Task B1 toProngs A and C and to the community insummary data files and in presentations andpublications.

2.5.1.3 Task C1: Assess aerosol radiativeforcing for the ACE-Asia region by combiningsatellite and suborbital results, including those


from Prongs A and B. Quantify uncertaintiesvia sensitivity studies that combineuncertainties in input parameters withsensitivities of outputs to inputs. Devotespecial efforts to cloud effects, both on thesatellite retrievals and on radiative fluxchanges. Quantify the benefit of using aconsistent model in satellite retrievals and flux-change calculations.

2.5.1.4 Task C2: Provide results of Task C1 tothe community in summary data files and inpresentations and publications.

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

2.5.2.1 Task A3: Complete the publication ofthe ACE-Asia absorption results. Complete theanalysis, presentation, and publication of SGPAerosol IOP absorption results, including anassessment of the accuracy improvementresulting from the stabilized radiometerplatform. Synthesize the overall results interms of aerosol absorption and SSA spectrafor major aerosol types. Compare to results ofother measurements and previous studies,sorting results by aerosol type.

2.5.2.2 Task B3: Complete the publication ofthe ACE-Asia extinction closure results.Complete the analysis, presentation, andpublication of SGP Aerosol IOP results,including a synthesis of results in terms ofuncertainties in key parameters as a function ofaerosol and surface condition (e.g., over watervs. land) and measurement type, includingabsorption results of Prong A.

2.5.2.3 Task C3: Complete the publication ofthe ACE-Asia regional forcing results, and theanalysis, presentation, and publication of SGPAerosol IOP results. Include a synthesis ofresults in terms of satellite retrieval type,aerosol type, surface condition (e.g., over watervs. land) and cloud condition. Assessimplications for forcing by aerosol type in themajor aerosol-influenced regions of the world.Emphasize quantification and reduction of theuncertainties cited by NACIP (Ramanathan etal., 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 bysoot, Science, 288, 1042-1047, 2000.

Ackerman, S.A. and S.K. Cox: Shortwaveradiative parameterization of largeatmospheric aerosols: dust and water clouds.J. Geophys. Res., 93, 11063-11073, 1988.

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

Bergstrom, R. W., P. B. Russell, and P.Hignett, Wavelength dependence of theabsorption of black carbon particles:Predictions and results from the TARFOXexperiment and implications for the aerosolsingle scattering albedo, J. Atmos. Sci., 59,568-578, 2002a.

Bergstrom, R.W., P. Pilewskie, B. Schmid, andP.B. Russell, Comparison of measured andpredicted aerosol radiative effects duringSAFARI 2000, J. Geophys. Res., submitted,2002b.

Bucholtz, A., D. L. Westphal, and S. A.Christopher, The springtime radiative forcingof aerosols over the Eastern Asia/WesternPacific region, Paper P1.7, 11th Conf. Atmos.Rad., Amer. Meteor. Soc., Ogden, Utah, 3-7June 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 aerosolsfrom Asia and their radiative effects over theWestern Pacific: A 3-D model study forACE-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 Caribbeanduring PRIDE: Part 2. Transport, verticalprofiles, and deposition in simulations of insitu 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 situaerosol size distributions and clear columnradiative closure during ACE 2. Tellus B 52,498-525, 2000.

Collins, W. D., Effects of clouds on directradiative forcing by absorptive aerosols,


Paper 1.3, 11t h Conf. Atmos. Rad., Amer.Meteor. Soc., Ogden, Utah, 3-7 June 2002.

Crowther, B.G., The design, construction, andcalibration of a spectral diffuse globalirradiance meter. Ph.D. Thesis, University ofArizona, 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 propertiesand water vapor among ground and airbornelidars 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 satellitemeasurements of aerosol optical propertiesand 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 aerosolspatial distribution and optical propertiesover the Atlantic Ocean during a Europeanpollution 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 Surfacesand 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., andJonsson, H. Influence of humidity on theaerosol scattering coefficient and its effect onthe upwelling radiance during ACE-2. TellusB 52, 546-567, 2000.

Hartley, W. S., P. V. Hobbs, J. L. Ross, P. B.Russell and J. M. Livingston, Properties ofaerosols aloft relevant to direct radiativeforcing off the mid-Atlantic coast of theUnited States, J. Geophys. Res. 105, 9859-9886, 2000.

Hegg, D. A., J. Livingston, P. V. Hobbs, T.Novakov, and P. B. Russell, Chemicalapportionment of aerosol column opticaldepth off the Mid-Atlantic coast of the

United States, J. Geophys. Res, 102, 25,293-25,303, 1997.

Higurashi, A. and T. Nakajima, Aerosol typeclassification with SeaWiFS four-channelradiance data. Presented at AMS RadiationConference, Ogden UT, 3-7 June 2002.

Hsu, N. C., Tsay, S, Herman, J Holben, B,Comparisons of satellite retrieval of aerosolproperties from SeaWiFS and TOMS to theAERONET measurements, EOS Trans.AGU, 82 (47), Spring Meet. Suppl., AbstractA51B-03, 2002.

Huebert, B., et al., ACE-Asia ProjectProspectus, 30 December 1999. Available athttp://saga.pmel.noaa.gov/aceasia/prospectus2000/

Husar, R. B., J. M. Prospero and L. L. Stowe,Characterization of tropospheric aerosolsover the oceans with the NOAA advancedvery high resolution radiometer opticalthickness operational product, J. Geophys.Res., 102, 16,889–16,909, 1997.

Ingold, T., B. Schmid, et al., Modeled andempirical approaches for retrieving columnarwater vapor from solar transmittancemeasurements in the 0.72, 0.82 and 0.94-umabsorption 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 watervapor profiles during TARFOX, J. Geophys.Res., 105, 9903-9916, 2000.

Kiedron P., J. Michalsky, B. Schmid, et al., Arobust retrieval of water vapor column in dryArctic conditions using the RotatingShadowband Spectroradiometer. J. Geophys.Res., 106(D20), 24007-24016, 2001.

Kuzmanoski, M., G. Box, M. Box, P. Russell,B. Schmid, Aerosol properties frominternational field campaigns, 9th NationalConference, Australian Meteorological andOceanographic Society, University ofMelbourne, 18-20 February, 2002.

Levy, J., Aerosol-Climate Interactions Program- (ACIP), Program Announcement for Officeof Global Programs, National Oceanic andA t m o s p h e r i c A d m i n i s t r a t i o n,http://www.ogp.noaa.gov/c&gc/ao/2003/index.htm, 2002a.

Levy, J., Aerosol-Climate Interactions Program( A C I P ) H o m e P a g e ,http://www.ogp.noaa.gov/mpe/acip/index.htm, 2002b.


Levy, J., New findings highlight thesignificance of aerosols in the Earth’sClimate System, 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 theMODIS retrievals of dust aerosol over theocean during PRIDE, J. Geophys. Res.,submitted, 2002.

Livingston, J. M., et al. (w. B. Schmid, P. B.Russell), Shipboard sunphotometermeasurements of aerosol optical depthspectra and columnar water vapor duringACE 2 and comparison to selected land, ship,aircraft, and satellite measurements, Tellus B,52, 594-619, 2000.

Livingston, J.M., et al., ACE-Asia AerosolOptical Depth and Water Vapor Measured byAirborne Sunphotometers and Related toOther Measurements and Calculations, FallAGU Meeting, San Francisco, 10-14December 2001.

Livingston, J. M., et al., Airbornesunphotometer measurements of aerosoloptical depth and columnar water vaporduring the Puerto Rico Dust Experiment, andcomparison with land, aircraft, and satellitemeasurements, J. Geophys. Res., submitted,2002.

Kurucz, R.L., Synthetic infrared spectra, inInfrared 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 lightscattering, light absorption and singlescattering albedo during the dry, biomassburning season in southern Africa andcomparisons of in situ and remote sensingmeasurements of aerosol optical depths, J.Geophys. Res., submitted, 2002.

Matsumoto, T., P. Russell, C. Mina, W. VanArk, and V. Banta, Airborne trackingsunphotometer, J. Atmos. Ocean. Tech., 4,336-339, 1987.

McGill M., D. Hlavka, W. Hart, J. Spinhirne,S. Scott, and B. Schmid. The Cloud PhysicsLidar: Instrument Description and InitialMeasurement Results. Appl. Opt. 2002 (inpress).

Mlawer, E.J., et al., Radiative transfer forinhomogeneous atmospheres: RRTM, avalidated correlated-k model for thelongwave. J. Geophys. Res., 102, 4353-4356,1997.

National Academy of Sciences Committee onthe Science of Climate Change, ClimateChange Science: An Analysis of Some KeyQuestions, ISBN 0-309-07574-2, NationalAcademy Press (http://www.nap.edu), 2001.

Pilewskie P, Rabbette M, Bergstrom R,Marquez J, Schmid B, Russell PB, Thediscrepancy between measured and modeleddownwelling 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, etal., Solar spectral radiative forcing during theSouth African Regional Science Initiative. J.Geophys. Res. Accepted for publication,2002a.

Pilewskie, P., R. Bergstrom, M. Rabbette,J.Pommier, and S. Howard, Cloud solarspectral 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 radiativeforcing by Saharan dust during the PueroRico Dust Experiment. J. Geophys. Res.Submitted, 2002c.

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

Rabbette , M. and P. Pilewskie, Multivariateanalysis of solar spectral irradiancemeasurements. J. Geophys. Res., 106, D9,9685-9696 (2001).

Rabbette, M. and P. Pilewskie, Principalcomponent analysis of Arctic solar irradiancespectra. J. Geophys. Res. in press, 2002.

Raes, F., Bates, T., McGovern, F., vanLiedekerke, M., The Second AerosolCharacterization Experiment (ACE-2):general overview and main results. Tellus52B, 111-125, 2000.

Ramanathan, V, et al., Indian OceanExperiment: An integrated analysis of theclimate 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 InteractionsProgram (NACIP), A National ResearchImperative, White Paper, http://www-NACIP/ucsd.edu, 2002.

Rasch, P. J., and W. D. Collins, Estimatingnatural variability of Asian aerosols;Relationship of ACE-Asia to the 1990s, EOSTrans. 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, Retrievingthe vertical structure of the effective aerosolcomplex index of refraction from acombination of aerosol in situ and remotesensing measurements during TARFOX, J.Geophys. Res. 105, 9949-9970, 2000a.

Redemann, J., et al. (w. P. B. Russell), Casestudies of the vertical structure of theshortwave direct aerosol radiative forcingduring TARFOX, J. Geophys. Res., 105,9971-9979, 2000b.

Redemann, J., P.B. Russell, and P. Hamill,Dependence of aerosol light absorption andsingle scattering albedo on ambient relativehumidity for sulfate aerosols with blackcarbon cores, J. Geophys. Res., 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 aerosoloptical depth and columnar water vaporduring ACE-Asia, American Association forAerosol Research Annual Meeting, Portland,Oregon, 15-19 October 2001b.

Redemann, J., B. Schmid, P. Russell, J.Livingston, et al., Towards a determination ofaerosol radiative effects in the Pacific Basintroposphere based on aerosol extinction andoptical depth closure studies aboard theNCAR C-130 in ACE-Asia, First ACE-AsiaData Workshop, Pasadena, CA, 29 October-1November 2001c.

Redemann, J., B. Schmid, J. M. Livingston, P.B. Russell, et al., Airborne SunphotometerMeasurements of Aerosol Optical Depth andWater Vapor in ACE-Asia and theirComparisons to Correlative Measurementsand Calculations, Abstracts, 11th Conferenceon 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 dusttransported into the Caribbean during thePuerto 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., TheAtmospheric Radiation Measurement (ARM)Program’s Water Vapor IntensiveObserva t ion Per iods : Overv iew,accomplishments, and future challenges.Bull. Amer. Meteor. Soc. (submitted), 2001.

Russell, P. B., and J. Heintzenberg, Anoverview of the ACE 2 Clear Sky ColumnClosure Experiment (CLEARCOLUMN),Tellus B, 52, 463-483, 2000.

Russell, P. B., P. V. Hobbs, and L. L. Stowe,Aerosol properties and radiative effects in theUnited States east coast haze plume: Anoverview of the Tropospheric AerosolRadiative 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 UnitedStates Mid-Atlantic coast: Comparison ofvalues calculated from sunphotometer and insitu data with those measured by airbornepyranometer, J. Geophys. Res., 104, 2289-2307, 1999b.

Russell, P. B., B. Schmid, J. Redemann, J. M.Livingston, R. W. Bergstrom, P. Pilewskie, etal., Airborne sunphotometer studies ofaerosol properties and effects, includingclosure among satellite, suborbital remote,and in situ measurements, 8th ScientificAssembly 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 ofACE-Asia Spring 2001 Investigations onAerosol Radiative Effects and Related


Aerosol Properties, Fall AGU Meeting, SanFrancisco, 10-14 December 2001b.

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

Russell, P.B., et al., Overview of ACE-AsiaSpring 2001 Investigations on Aerosol-Radiation Interactions, Abstracts , 11th

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 aerosoloptical depth from four solar radiometersduring the Fall 1997 ARM IntensiveObservation Period, Geophys. Res. Lett., 17,2725-2728, 1999.

Schmid, B., J. M. Livingston, P. B. Russell, etal., Clear sky closure studies of lowertropospheric aerosol and water vapor duringACE-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 columnarwater-vapor measurements from solartransmittance 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., Coordinatedairborne, spaceborne, and ground-basedmeasurements of massive, thick aerosollayers during the dry season in SouthernAfrica, J. Geophys. Res., accepted, 2002.

Stamnes, K., S.-C. Tsay, W. Wiscombe and K.Jayaweera, A numerically stable algorithmfor discrete-ordinate-method radiativetransfer in multiple scattering and emittinglayered 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 continuouswave cavity ring-down techniques, submittedto J. Atmos. Oceanic. Tech., 2002.

Turner, D.D., R.A. Ferrare, L.A. Heilman,W.F. Feltz, and T. Tooman, Automatedretrievals of water vapor and aerosol profilesover Oklahoma from an operational Ramanlidar, 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 modelingoverview, EOS Trans. AGU, 82 (47), FallMeet. 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 multiwavelengthextinction derived from particle size andcomposition with results from sunphotometryJ. 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 opticalthickness over the Atlantic Ocean duringPRIDE, 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 aerosolsduring ACE 2: Instrument description,results, and comparisons with other ground-based and airborne measurements. Tellus B52, 636-651, 2000.

Welton, E. J., J. R. Campbell, J. D. Spinhirne,and V. S. Scott, "Global monitoring of cloudsand aerosols using a network of micro-pulselidar systems ", in Lidar Remote Sensing forIndustry 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 inthe Yangtze delta region of China:observation and model estimation, J .Geophys . Res . , submitted, 2002.


4. STAFFING, RESPONSIBILITIES,AND VITAE

Dr. Philip Russell will be Lead PrincipalInvestigator. As such, he will supervise thework, lead the planning, and participate in theanalyses, as well as selected presentations andpublications. He will be responsible for thecompletion of the work within budget andschedule. Drs. Peter Pilewskie, Beat Schmid andJens Redemann will be Co-PIs for Prongs A, B,

and C, respectively, each responsible for leadinghis respective prong and coordinating it with theothers. Dr. Robert Bergstrom will play key rolesin Prongs A and C, including leading andfacilitating the use of his radiative transfermodel to (i) derive single scattering albedosfrom SSFR and AATS measurements and (ii)calculate regional radiative forcings. Ames willfurnish additional personnel necessary toaccomplish the research.

(a) Philip B. RussellAbbreviated Curriculum Vitae

B.A., Physics, Wesleyan University (1965, Magna cum Laude; Highest Honors). M.S. andPh.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 ofChicago and NCAR). Physicist to Senior Physicist, Atmospheric Science Center, SRIInternational (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-DisciplinaryScience (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 atmosphericresearch).

Previously, Mission Scientist for ACE-Asia C-130 flights addressing aerosol-radiationinteractions. Co-coordinator for the CLEARCOLUMN component of IGAC’s Second AerosolCharacterization Experiment (ACE-2). Coordinator for IGAC’s Tropospheric Aerosol RadiativeForcing Observational Experiment (TARFOX). Member, Science Teams for SAGE II and SAGEIII (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 CouncilCommittee on Army Basic Research (1979-81).

Previously, Project Scientist, Small High-Altitude Science Aircraft (SHASA) Project to developthe Perseus A Remotely Piloted Aircraft (RPA, 1992-94). Member, NASA Red Team on RemoteSensing and Environmental Monitoring of Planet Earth (1992-3). Leader, NASA Ames EarthScience Advanced Aircraft (ESAA) Team (1990-94).

NASA Exceptional Service Medal (1988, for managing Stratosphere-Troposphere ExchangeProject). NASA Space Act Award (1989, for invention of Airborne AutotrackingSunphotometer). 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 diversetechniques 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 ClosureExperiment (CLEARCOLUMN), Tellus B 52, 463-483, 2000.

Bergstrom, R. W., and P. B. Russell, Estimation of aerosol radiative effects over the mid-latitudeNorth 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 theUnited States Mid-Atlantic haze plume: An overview of the Tropospheric Aerosol RadiativeForcing Observational Experiment (TARFOX), J. Geophys. Res., 104, 2213-2222, 1999.

Russell, P. B., S. Kinne and R. Bergstrom, Aerosol climate effects: Local radiative forcing andcolumn closure experiments, J. Geophys. Res., 102, 9397-9407, 1997.

Russell, P. B., et al. Global to microscale evolution of the Pinatubo volcanic aerosol, derivedfrom 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: airbornetracking 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: anintroduction 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 PilewskieAbbreviated Curriculum VitaeNASA Ames Research Center

MS 245-4, Moffett Field CA 94035-1000

Education:

B.S., Meteorology, Pennsylvania State University, 1983M.S., Atmospheric Science, University of Arizona, 1986Ph.D., Atmospheric Science, University of Arizona, 1989

Professional Experience:

Radiation Group Leader, Atmospheric Physics Branch, NASA Ames Research Center, 1994-presentResearch Scientist, Atmospheric Physics Branch, NASA Ames Research Center, 1989-1994Research 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-presentMember, Triana Science Team, 1998-presentMember, Global Aerosol Climatology Program (GACP), 1998-presentMember, Atmospheric Radiation Measurement Program (ARM) Science Team, 1997-presentMember, International Global Atmospheric Chemistry (IGAC), Focus on Atmospheric Aerosols,

Direct Aerosol Radiative Forcing Activity, 1995-1999Member, First International Satellite Cloud Climatology Program (ISCCP) Regional Experiment,


Phase III (FIRE III) Science Team, 1994-presentScience Team Leader, International Global Aerosol Program (IGAP), Radiative Effects ofAerosols, 1993

Professional Honors:

NASA Exceptional Scientific Achievement Medal, 1997NASA Group Achievement Award, FIRE Phase II Science and Operations Team, 1997NASA 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 RegionalScience Initiative. J. Geophys. Res. accepted, 2002.

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

Pilewskie, P., R. Bergstrom, J. Reid, H. Jonsson, S. Howard, and J.Pommier, J. Livingston, andP. 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 PuertoRico 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, Thediscrepancy between measured and modeled downwelling solar irradiance at the ground:Dependence on water vapor. Geophys. Res. Lett. 25, 137, 2000.

(c) Beat SchmidAbbreviated Curriculum Vitae

Bay Area Environmental Research Institute560 Third Street West, Sonoma, CA 95476

EducationM.S. 1991 Institute of Applied Physics, University of Bern, SwitzerlandPh.D. 1995 Institute of Applied Physics, University of Bern, Switzerland

Professional ExperienceBay Area Environmental Research Institute, Sonoma, CA (1997-Present): Senior ResearchScientistUniversity of Arizona, Tucson, AZ (Oct. 1995 -Jan. 1996): Visiting ScientistUniversity of Bern, 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 aerosoloptical depth and size distribution, H2O and O3.

• Participated with the NASA Ames Airborne Sun photometers in ACE-2 (North AtlanticRegional Aerosol Characterization Experiment, 1997), SAFARI 2000 (Southern AfricanRegional 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 2000intensive 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 OpticsStudy (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 aerosoloptical depth and columnar water vapor during the Puerto Rico Dust Experiment, andcomparison 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: Comparisonof multiwavelength extinction derived from particle size and composition with results fromsunphotometry J. Geophys. Res., submitted, 2002.

Pilewskie, P., et al., incl, B. Schmid, Solar Spectral Radiative Forcin

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