HR: 08:00h
AN: A51B-06    [Abstracts]
TI: Estimates of Shortwave Aerosol Forcing From the Data of Ground-Based Networks With Account of Coarse Particles
AU: * Rublev, A
EM: rublev@imp.kiae.ru
AF: Russian Research Center "Kurchatov Institute", Kurchatov sq.,1, Moscow, 123182, Russian Federation
AU: Gorchakova, I
EM: gor@omega.ifaran.ru
AF: Obukhov Institute of Atmospheric Physics, Pyzhevsky str., 3, Moscow, 119017, Russian Federation
AU: Udalova, T
EM: udalova@imp.kiae.ru
AF: Russian Research Center "Kurchatov Institute", Kurchatov sq.,1, Moscow, 123182, Russian Federation
AB: Beginning with approximately late 1990-th, a surplus (up to 0.1-0.2) in magnitudes of Single Scattering Albedo (SSA) for smoke and dust aerosols has been observed in comparison with the estimates of former years. According to the new data, shortwave aerosol forcing has changed its magnitude and even the sign. For example, as it was underlined in papers published in 2001-2002 by our colleagues from the NASA, a dust plume of the Saharan aerosol absorbs sunlight much less than it had been considered earlier. According to their estimates obtained on the basis of independent ground and space observations, the dust absorbs only 1-5 % of the incident solar radiation instead of 10-15 % as it was considered before. Such decrease in estimates of solar absorption can be attributed to the SSA value of dust aerosol which increased up to 0.95-0.98 in the visible spectrum. One of the possible explanations of this difference in the former and new results could be the incorrect account of optical properties inherent in coarse particles in the determination of aerosol parameters and in subsequent calculations of radiative fluxes. Coarse particles in combination with large optical thickness, typical for fire smokes and dust storms, require a modification of the existing algorithms for processing the data, received from ground-based measuring networks such as AERONET and USDA to provide stability of retrieval of aerosol optical and microphysical parameters. The existing methods of processing the measurements of these networks do not consider particles with radiuses greater than 15 mkm. Such modifications have been made using the analysis of the accessible simultaneous network data by CIMEL and MFRSR photometers. The obtained estimates of shortwave aerosol forcing show that the total solar radiation absorbed by the atmosphere and sandy surface during the storm is greater than it is in the quiet atmosphere. This result is in agreement with the "historic" data obtained, for example, during the USSR-US experiment in Tajikistan in 1989.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly