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Radiative Flux Changes by Aerosols from North America, Europe, and Africa over the Atlantic Ocean: Measurements and Calculations from TARFOX and ACE-2Aerosol effects on atmospheric radiative fluxes provide a forcing function that is a major source of uncertainty in understanding the past climate and predicting climate change. To help reduce this uncertainty, the 1996 Tropospheric Aerosol Radiative Forcing Experiment (TARFOX) and the 1997 second Aerosol Characterization Experiment (ACE-2) measured the properties and radiative effects of American, European, and African aerosols over the Atlantic. In TARFOX, radiative fluxes and microphysics of the American aerosol were measured from the UK C-130 while optical depth spectra, aerosol composition, and other properties were measured by the University of Washington C-131A and the CIRPAS Pelican. Closure studies show that the measured flux changes agree with those derived from the aerosol measurements using several modelling approaches. The best-fit midvisible single-scatter albedos (approx. 0.89 to 0.93) obtained from the TARFOX flux comparisons are in accord with values derived by independent techniques. In ACE-2 we measured optical depth and extinction spectra for both European urban-marine aerosols and free-tropospheric African dust aerosols, using sunphotometers on the R/V Vodyanitskiy and the Pelican. Preliminary values for the radiative flux sensitivities (Delta Flux / Delta Optical depth) computed for ACE-2 aerosols (boundary layer and African dust) over ocean are similar to those found in TARFOX. Combining a satellite-derived optical depth climatology with the aerosol optical model validated for flux sensitivities in TARFOX provides first-cut estimates of aerosol-induced flux changes over the Atlantic Ocean.
Document ID
20020069112
Document Type
Preprint (Draft being sent to journal)
Authors
Russell, P. B. (NASA Ames Research Center Moffett Field, CA United States)
Hignett, P. (United Kingdom Meteorological Office United Kingdom)
Livingston, J. M. (SRI International Corp. Menlo Park, CA United States)
Schmid, B. (Bay Area Environmental Research Inst. San Francisco, CA United States)
Chien, A. (Symtech Corp. Moffett Field, CA United States)
Bergstrom, R. (Bay Area Environmental Research Inst. San Francisco, CA United States)
Durkee, P. A. (Naval Postgraduate School Monterey, CA United States)
Hobbs, P. V. (Washington Univ. Seattle, WA United States)
Bates, T. S. (National Oceanic and Atmospheric Administration Seattle, WA United States)
Quinn, P. K. (National Oceanic and Atmospheric Administration Seattle, WA United States)
Condon, Estelle
Date Acquired
September 7, 2013
Publication Date
September 7, 1998
Subject Category
Geophysics
Meeting Information
Fifth International Aerosol Conference(Edinburgh, Scotland)
Funding Number(s)
PROJECT: RTOP 622-44-10-10
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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