HR: 1340h
AN: A23A-0917    [Abstracts]
TI: The impact of deep convective cumulus clouds on surface, TOA, and atmosphere radiation budgets at the DOE ARM TWP and SGP sites
AU: * Xi, B
EM: baike@aero.und.edu
AF: University of North Dakota, Dept. of Atmospheric Sci., Grand Forks, ND 58201 United States
AU: Dong, X
EM: dong@aero.und.edu
AF: University of North Dakota, Dept. of Atmospheric Sci., Grand Forks, ND 58201 United States
AU: Wielicki, B
EM: b.a.wielicki@nasa.gov
AF: NASA Langlry Research Center, LARC, Hampton, VA 23606 United States
AU: Hu, y
EM: Y.HU@larc.nasa.gov
AF: NASA Langlry Research Center, LARC, Hampton, VA 23606 United States
AU: Benson, S
EM: sbenson@met.utah.edu
AF: University of Utah, Dept. of Meteorology, Salt Lake, UT 84112 United States
AU: Mace, J
EM: mace@met.utah.edu
AF: University of Utah, Dept. of Meteorology, Salt Lake, UT 84112 United States
AB: The surface, TOA, and atmosphere SW radiation budgets for deep convective clouds at the Department of Energy Atmosphere Radiation Measurement (ARM) Tropical Western Pacific (TWP) and Southern Great Plains (SGP) sites are studies using DOE ARM surface and NASA CERES SW flux measurements during March 2000-December 2004 period. A total of 111 cases for TERRA and 78 cases for AQUA over the TWP sites, and 78 cases for TERRA and 59 cases for AQUA over the SGP site are selected during the period. The surface data, including lidar-derived cloud-base height Zbase, radar-derived cloud-top height Ztop, and PSP-measured solar transmission (Tsfc), were averaged over a 2-hour period centered at the time of the NASA Terra and Aqua satellite overpass the ARM sites. The corresponding MODIS cloud properties, including effective cloud height Zeff, cloud optical depth, and TOA albedo RTOA, were averaged in a 1 x 1 degree box centered on the ARM sites. At the TWP sites, the averaged optical depth, TOA albedo, surface transmission, and atmospheric absorption are 54.7 (51.0), 0.60 (0.58), 0.16 (0.16), and 0.24 (0.27), respectively, during TERRA (AQUA) overpass. At the SGP site, they are 46.3 (53.9), 0.60 (0.60), 0.18 (0.17), and 0.22 (0.24), respectively, during TERRA (AQUA) overpass. The TOA albedo increase, surface transmission decreases with increasing optical depth, while it is almost no relationship between atmospheric absorption and cloud optical depth. A linear relationship (negative) between TOA albedo and surface transmission has been found. A sensitivity study has shown that atmospheric absorption tends to be constant (~0.24) for higher cloud optical depth (>50), and water vapor above and below clouds almost contributes nothing to it. With closely matched satellite and surface data, the averaged atmospheric absorptions from both observations and Fu-Liou calculations are the same (~0.24).
DE: 0321 Cloud/radiation interaction
DE: 3359 Radiative processes
DE: 3360 Remote sensing
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005