HR: 1340h
AN: H33C-1458    [Abstracts]
TI: Simulations of the Amazon Hydrologic Cycle Using a Coupled Land-Atmosphere General Circulation Model
AU: * Harper, A
EM: abharper@atmos.colostate.edu
AF: Colorado State University Department of Atmospheric Sciences, 1371 Atmospheric Science, Fort Collins, CO 80523-1371, United States
AU: Denning, S A
EM: denning@atmos.colostate.edu
AF: Colorado State University Department of Atmospheric Sciences, 1371 Atmospheric Science, Fort Collins, CO 80523-1371, United States
AU: Baker, I
EM: baker@atmos.colostate.edu
AF: Colorado State University Department of Atmospheric Sciences, 1371 Atmospheric Science, Fort Collins, CO 80523-1371, United States
AU: Branson, M
EM: mark@atmos.colostate.edu
AF: Colorado State University Department of Atmospheric Sciences, 1371 Atmospheric Science, Fort Collins, CO 80523-1371, United States
AU: Dazlich, D
EM: dazlich@atmos.colostate.edu
AF: Colorado State University Department of Atmospheric Sciences, 1371 Atmospheric Science, Fort Collins, CO 80523-1371, United States
AB: Land-atmosphere interactions have a profound effect on our weather and climate. Previous modeling studies have shown that these interactions are of particular importance in the Amazon Basin, where the predicted effects of climate change include reduced precipitation. Specifically, moisture fluxes from the land surface both affect and are affected by the large-scale circulation and precipitation. The rainforest is already fairly drought resistant, being able to withstand several months in a row with little to no rainfall. Understanding the mechanisms that allow this resistance is important for planning for the future climate. To study these interactions, we have coupled a land surface model (the Simple Biosphere Model – SiB3), to Colorado State University's General Circulation Model (BUGS5). In a previously coupled version of the models, rainfall gradually decreased in the Amazon Basin over a three-year period due to decreased moisture recycling, until the wet season was indistinguishable from the dry season. SiB3 includes improved representations of the vertical distribution of groundwater, more realistic root profiling and an improved response of the vegetation to drought stress. Results from multiyear runs show that these improvements allow the forest to function more realistically and that the representation of the Amazon hydrologic cycle is improved. Attention is paid to particular changes within the land surface model and their effects on the results.
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
DE: 1655 Water cycles (1836)
DE: 3322 Land/atmosphere interactions (1218, 1631, 1843)
DE: 3337 Global climate models (1626, 4928)
DE: 3354 Precipitation (1854)
SC: Hydrology [H]
MN: 2007 Fall Meeting