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MODIS Observation of Aerosols over Southern Africa During SAFARI 2000: Data, Validation, and Estimation of Aerosol Radiative ForcingAerosol properties, including optical thickness and size parameters, are retrieved operationally from the MODIS sensor onboard the Terra satellite launched on 18 December 1999. The predominant aerosol type over the Southern African region is smoke, which is generated from biomass burning on land and transported over the southern Atlantic Ocean. The SAFARI-2000 period experienced smoke aerosol emissions from the regular biomass burning activities as well as from the prescribed burns administered on the auspices of the experiment. The MODIS Aerosol Science Team (MAST) formulates and implements strategies for the retrieval of aerosol products from MODIS, as well as for validating and analyzing them in order to estimate aerosol effects in the radiative forcing of climate as accurately as possible. These activities are carried out not only from a global perspective, but also with a focus on specific regions identified as having interesting characteristics, such as the biomass burning phenomenon in southern Africa and the associated smoke aerosol, particulate, and trace gas emissions. Indeed, the SAFARI-2000 aerosol measurements from the ground and from aircraft, along with MODIS, provide excellent data sources for a more intensive validation and a closer study of the aerosol characteristics over Southern Africa. The SAFARI-2000 ground-based measurements of aerosol optical thickness (AOT) from both the automatic Aerosol Robotic Network (AERONET) and handheld Sun photometers have been used to validate MODIS retrievals, based on a sophisticated spatio-temporal technique. The average global monthly distribution of aerosol from MODIS has been combined with other data to calculate the southern African aerosol daily averaged (24 hr) radiative forcing over the ocean for September 2000. It is estimated that on the average, for cloud free conditions over an area of 9 million square kin, this predominantly smoke aerosol exerts a forcing of -30 W/square m C lose to the terrestrial surface and -10 W/square m at the top of the atmosphere (TOA). While cooling the surface and Earth system, the difference of 20 W/square m is energy that heats the atmosphere.
Document ID
20020023593
Document Type
Conference Paper
Authors
Ichoku, Charles (NASA Goddard Space Flight Center Greenbelt, MD United States)
Kaufman, Yoram (NASA Goddard Space Flight Center Greenbelt, MD United States)
Remer, Lorraine (NASA Goddard Space Flight Center Greenbelt, MD United States)
Chu, D. Allen (NASA Goddard Space Flight Center Greenbelt, MD United States)
Mattoo, Shana (NASA Goddard Space Flight Center Greenbelt, MD United States)
Tanre, Didier (Centre National de la Recherche Scientifique Villeneuve d'Ascq France)
Levy, Robert (NASA Goddard Space Flight Center Greenbelt, MD United States)
Li, Rong-Rong (NASA Goddard Space Flight Center Greenbelt, MD United States)
Kleidman, Richard (NASA Goddard Space Flight Center Greenbelt, MD United States)
Lau, William K. M.
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Environment Pollution
Meeting Information
2001 Fall AGU Meeting(San Francisco, CA)
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.