HR: 17:05h
AN: A54B-04    [Abstracts]
TI: Effect of Aerosols on Surface Radiation and Air Quality in the Central American Region Estimated Using Satellite UV Instruments
AU: * Bhartia, P K
EM: pawan.bhartia@nasa.gov
AF: NASA Goddard Space Flight Center, Mail Code 613.3, Greenbelt, MD 20771, United States
AU: Torres, O
EM: torres@tparty.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Mail Code 613.3, Greenbelt, MD 20771, United States
AU: Krotkov, N A
EM: krotkov@tparty.gsfc.nasa.gov
AF: NASA Goddard Space Flight Center, Mail Code 613.3, Greenbelt, MD 20771, United States
AB: Solar radiation reaching the Earth's surface is reduced by both aerosol scattering and aerosol absorption. Over many parts of the world the latter effect can be as large or larger than the former effect, and small changes in the aerosol single scattering albedo can either cancel the former effect or enhance it. In addition, absorbing aerosols embedded in clouds can greatly reduce the amount of radiation reaching the surface by multiple scattering. Though the potential climatic effects of absorbing aerosols have received considerable attention lately, their effect on surface UV, photosynthesis, and photochemistry can be equally important for our environment and may affect human health and agricultural productivity. Absorption of all aerosols commonly found in the Earth's atmosphere becomes larger in the UV and blue wavelengths and has a relatively strong wavelength dependence. This is particularly true of mineral dust and organic aerosols. However, these effects have been very difficult to estimate on a global basis since the satellite instruments that operate in the visible are primarily sensitive to aerosol scattering. A notable exception is the UV Aerosol Index (AI), first produced using NASA's Nimbus-7 TOMS data. AI provides a direct measure of the effect of aerosol absorption on the backscattered UV radiation in both clear and cloudy conditions, as well as over snow/ice. Although many types of aerosols produce a distinct color cast in the visible images, and aerosols absorption over clouds and snow/ice could, in principle be detected from their color, so far this technique has worked well only in the UV. In this talk we will discuss what we have learned from the long-term record of AI produced from TOMS and Aura/OMI about the possible role of aerosols on surface radiation and air quality in the Central American region.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0360 Radiation: transmission and scattering
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly