HR: 17:50h
AN: H24D-07    [Abstracts]
TI: Effects of water table dynamics on regional climate
AU: * Xie, Z
EM: zxie@lasg.iap.ac.cn
AF: Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, Beijing, 100029, China
AU: Yuan, X
EM: xyuan@mail.iap.ac.cn
AF: Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, Beijing, 100029, China
AU: Zheng, J
EM: jzheng@mail.iap.ac.cn
AF: Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, Beijing, 100029, China
AB: Water table is an important component of hydrologic cycle and its anomaly will result in variations of soil moisture, water and energy balances between the land surface and atmosphere, which will ultimately influence climate. In this work, we investigate the effects of water table dynamics on regional climate by implementing a groundwater model into the regional climate model RegCM3. Three-month integrations with the coupled model (named RegCM3-GW) and the original climate model RegCM3 show that dynamical representation of water table in regional climate model changes the surface heat and moisture fluxes through modifying the vertical profile of soil moisture. The differences of simulated surface fluxes between RegCM3-GW and RegCM3 result in different structures of the boundary layer. For instance, the soil moisture simulated by the RegCM3-GW is wetter than that by the RegCM3 over northern China, which enhances the evapotranspiration and then increases cloud cover. Although the net shortwave absorbed by the soil decreases due to increased cloud cover, this effect is obscured by the decrease in net longwave emission. Thus the net radiative energy flux simulated by the RegCM3-GW is larger than that by the RegCM3, which provides more energy for the heating and moistening of the planetary boundary layer and builds a shallower boundary layer, and ultimately increases the potential for convective instability. In a short, RegCM3-GW produces more accurate monthly precipitation amount and geopotential height for the boundary atmosphere over semiarid areas, and the moisture tend to transport from the northeast of China to northern China as compared with RegCM3 because of the changes of circulation.
DE: 1833 Hydroclimatology
DE: 1840 Hydrometeorology
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 3322 Land/atmosphere interactions (1218, 1631, 1843)
DE: 3355 Regional modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting