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Airborne Sunphotometer Measurements of Aerosol Optical Depth and Water Vapor in ACE-Asia and Their Comparisons to Correlative MeasurementsIn the Spring 2001 phase of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia), the 6-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) operated on 15 of the 19 research flights of the NCAR C-130, while its 14-channel counterpart (AATS-14) flew successfully on all 19 research flights of the CIRPAS Twin Otter. ACE-Asia studied aerosol outflow from the Asian continent to the Pacific basin. It was designed to integrate suborbital and satellite measurements and models to reduce the uncertainty in calculations of the climate forcing due to aerosols. AATS-6 and AATS-14 measured solar beam transmission at six and 14 wavelengths (380-1021 and 354-1558 nm, respectively), yielding aerosol optical depth (AOD) spectra and columnar water vapor (CWV). Vertical differentiation in profiles yielded aerosol extinction spectra and water vapor concentration. In this paper, we plan to present examples of the following, preliminary findings that are based in part on our airborne sunphotometer measurements: (1) The wavelength dependence of sunphotometer-derived AOD and extinction indicates that supermicron dust was often a major component of the aerosol, frequently extending to high altitudes. The percentage of full-column AOD (525 nm) that Jay above 3 km was typically 34+/-13%. In contrast, the analogous percentage of columnar water vapor was only 10+/-4%; (2) Initial comparison studies between AOD data obtained by AATS-6 and AATS-14 during coordinated low-level flight legs show agreement well within the instruments' error bars; (3) Aerosol extinction has been derived from airborne in situ measurements of scattering (nephelometers) and absorption (particle soot/ absorption photometer, PSAP) or calculated from particle size distribution measurements (mobility analyzers and aerodynamic particle sizers). Comparison with corresponding extinction values derived from the Ames airborne sunphotometer measurements shows good agreement for the vertical distribution of aerosol layers. However, the level of agreement in absolute magnitude of the derived aerosol extinction/optical depth varied among the aerosol layers sampled; (4) Initial comparisons of sunphotometer and satellite-derived AOD using SeaWiFS, MISR and AVHRR show promising results. We also plan to include comparisons with MODIS and TOMS: (5) Initial comparisons of sunphotometer-derived AOD and aerosol extinction profiles with lidars in Tokyo and on a ship show reasonable agreement.
Document ID
20020072959
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Schmid, B.
(Bay Area Environmental Research Inst. Sonoma , CA United States)
Redemann, J.
(Bay Area Environmental Research Inst. Sonoma , CA United States)
Livingston, J.
(SRI International Corp. Menlo Park, CA United States)
Russell, P.
(NASA Ames Research Center Moffett Field, CA United States)
Hegg, D.
(Washington Univ. Seattle, WA United States)
Wang, J.
(California Inst. of Tech. Pasadena, CA United States)
Kahn, R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Hsu, C.
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Masonis, S.
(Washington Univ. Seattle, WA United States)
Murayama, T.
(Tokyo Univ. of Mercantile Marine Japan)
Hipskind, R. Stephen
Date Acquired
August 20, 2013
Publication Date
January 1, 2002
Subject Category
Environment Pollution
Meeting Information
Meeting: AGU Western Pacific Geophysics Meeting
Country: New Zealand
Start Date: July 9, 2002
End Date: July 12, 2002
Sponsors: American Geophysical Union
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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