HR: 18:05h
AN: A54B-08    [Abstracts]
TI: Impact of Arctic Aerosols on Solar Radiation at the Surface: Modeled versus Measured
AU: * Shettle, E P
EM: shettle@nrl.navy.mil
AF: NRL, Remote Sensing Division Code 7227, Washington, DC 20375-5351, United States
AU: Stone, R S
EM: Robert.Stone@noaa.gov
AF: CIRES, University of Colorado, Boulder, CO 80309, United States
AU: Stone, R S
EM: Robert.Stone@noaa.gov
AF: NOAA/ESRL, 325 Broadway, Boulder, CO 80305, United States
AU: Andrews, E
EM: Betsy.Andrews@noaa.gov
AF: CIRES, University of Colorado, Boulder, CO 80309, United States
AU: Andrews, E
EM: Betsy.Andrews@noaa.gov
AF: NOAA/ESRL, 325 Broadway, Boulder, CO 80305, United States
AU: Anderson, G P
EM: Gail.Anderson@noaa.gov
AF: NOAA/ESRL, 325 Broadway, Boulder, CO 80305, United States
AU: Anderson, G P
EM: Gail.Anderson@noaa.gov
AF: AFRL/VSB, 29 Randolph Rd, Hanscom AFB, MA 01731, United States
AU: Dutton, E G
EM: Ellsworth.G.Dutton@noaa.gov
AF: NOAA/ESRL, 325 Broadway, Boulder, CO 80305, United States
AU: Stohl, A
EM: ast@nilu.no
AF: NILU, PO Box 100, Kjeller, 2027, Norway
AU: Fromm, M D
EM: mike.fromm@nrl.navy.mil
AF: NRL, Remote Sensing Division Code 7227, Washington, DC 20375-5351, United States
AU: Berk, A
EM: lex@spectral.com
AF: SSI, 99 S Bedford St, Burlington, MA 01803, United States
AB: Aerosols in the Arctic affect the disposition of solar radiation within the lower atmosphere and at the surface in complex ways, attenuating solar and terrestrial radiation directly, while interacting indirectly with clouds. Aerosol radiative impacts depend on their chemical, physical and optical properties as well as solar geometry and properties of the intervening atmosphere and surface. While the Arctic atmosphere is generally very clean, incursions of both natural and anthropogenic aerosols produce perturbations that vary latitudinally and seasonally. To make accurate climate assessments it is essential to quantify the radiative forcing by the different aerosol types relative to normally clean background conditions. With the complement of instruments now operating at the NOAA and DOE facilities near Barrow, Alaska, it is possible to characterize Arctic aerosols, infer their optical properties and evaluate their radiative impact on the surface-atmosphere system. Successful closure experiments have been conducted in which empirical results have been used to corroborate model simulations. The approach has been applied to estimate the direct radiative forcing by dust from Asia and by smoke from boreal forest fires. The dust event occurred in April 2002 when snow covered the surface, while the smoke event took place in July 2004 after the snow had melted; thus, permitting evaluations to be made over a range of surface and atmospheric conditions. Given the good agreement between the measured and modeled forcings, it then becomes possible to model the impact of similar aerosols over a wider range of ambient and solar conditions, including characterization of the radiation that most affects photo-chemical and photo-biological processes.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0360 Radiation: transmission and scattering
DE: 0365 Troposphere: composition and chemistry
DE: 3311 Clouds and aerosols
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly