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Radiative Forcing Due to Enhancements in Tropospheric Ozone and Carbonaceous Aerosols Caused by Asian Fires During Spring 2008Simulations of tropospheric ozone and carbonaceous aerosol distributions, conducted with the Real-time Air Quality Modeling System (RAQMS), are used to study the effects of major outbreaks of fires that occurred in three regions of Asia, namely Thailand, Kazakhstan, and Siberia, during spring 2008. RAQMS is a global scale meteorological and chemical modeling system. Results from these simulations, averaged over April 2008, indicate that tropospheric ozone column increases by more than 10 Dobson units (DU) near the Thailand region, and by lesser amounts in the other regions due to the fires. Widespread increases in the optical depths of organic and black carbon aerosols are also noted. We have used an off-line radiative transfer model to evaluate the direct radiative forcing due to the fire-induced changes in atmospheric composition. For clear sky, the monthly averaged radiative forcing at the top of the atmosphere (TOA) is mostly negative with peak values less than -12 W/sq m occurring near the fire regions. The negative forcing represents the increased outgoing shortwave radiation caused by scattering due to carbonaceous aerosols. At high latitudes, the radiative forcing is positive due to the presence of absorbing aerosols over regions of high surface albedo. Regions of positive forcing at TOA are more pronounced under total sky conditions. The monthly averaged radiative forcing at the surface is mostly negative, and peak values of less than -30 W/sq m occur near the fire regions. Persistently large negative forcing at the surface could alter the surface energy budget and potentially weaken the hydrological cycle.
Document ID
20120007105
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Natarajan, Murali
(NASA Langley Research Center Hampton, VA, United States)
Pierce, R. Bradley
(National Environmental Satellite, Data, and Information Service Madison, WI, United States)
Lenzen, Allen J.
(Wisconsin Univ. Madison, WI, United States)
Al-Saadi, Jassim A.
(NASA Langley Research Center Hampton, VA, United States)
Soja, Amber J.
(National Inst. of Aerospace Hampton, VA, United States)
Charlock, Thomas P.
(NASA Langley Research Center Hampton, VA, United States)
Rose, Fred G.
(Science Systems and Applications, Inc. Hampton, VA, United States)
Winker, David M.
(NASA Langley Research Center Hampton, VA, United States)
Worden, John R.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 25, 2013
Publication Date
March 27, 2012
Publication Information
Publication: Journal of Geophysical Research - Atmospheres
Publisher: American Geophysical Union
Volume: 117
ISSN: 0148-0227
Subject Category
Geophysics
Report/Patent Number
NF1676L-13001
Funding Number(s)
WBS: WBS 281945.02.39.01.88
Distribution Limits
Public
Copyright
Other

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