HR: 14:40h
AN: B43H-05    [Abstracts]
TI: Global climate model simulations with a realistic representation of irrigation
AU: * Lobell, D
EM: dlobell@llnl.gov
AF: Lawrence Livermore National Lab, 7000 East Ave, Livermore, CA 94550,
AU: Bala, G
EM: bala@llnl.gov
AF: Lawrence Livermore National Lab, 7000 East Ave, Livermore, CA 94550,
AU: Mirin, A
EM: mirin@llnl.gov
AF: Lawrence Livermore National Lab, 7000 East Ave, Livermore, CA 94550,
AU: Phillips, T
EM: phillips14@llnl.gov
AF: Lawrence Livermore National Lab, 7000 East Ave, Livermore, CA 94550,
AU: Maxwell, R
EM: maxwell5@llnl.gov
AF: Lawrence Livermore National Lab, 7000 East Ave, Livermore, CA 94550,
AU: Rotman, D
EM: rotman1@llnl.gov
AF: Lawrence Livermore National Lab, 7000 East Ave, Livermore, CA 94550,
AB: Sensitivity studies with global and regional climate models have shown that replacing existing land cover with irrigated land can cause significant changes in climate. To provide a more realistic assessment of irrigation's influence, we performed a series of irrigation experiments with the Community Atmosphere Model (CAM). An irrigation fraction was computed for each grid cell based on FAO irrigation maps, and this fraction of agricultural area was then irrigated in the cell throughout an AMIP simulation (1980-1999). This experiment and a control simulation were performed both at 2-degree and half-degree spatial resolutions, with the latter aimed at resolving land use within heterogeneous areas such as California. Results are presented for changes in temperature, precipitation, humidity, runoff, and other variabiles. In addition, we evaluated whether irrigation reduced the bias of climatologies when compared to observed climate over the AMIP time period. Finally, we investigate the factors leading to regional differences in the response of climate to irrigation.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0439 Ecosystems, structure and dynamics (4815)
DE: 1622 Earth system modeling (1225)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1632 Land cover change
SC: Biogeosciences [B]
MN: 2007 Fall Meeting