HR: 08:00h
AN: H11G-01 INVITED     [Abstracts]
TI: Role of Groundwater Aquifers in the Climate System
AU: * Eltahir, E A
EM: eltahir@mit.edu
AF: Massachusetts Institute of Technology, Room 48-207, Cambridge, MA 02139
AU: Yeh, P J
EM: patyeh@hkucc.hku.hk
AF: The University of Hong Kong, Department of Civil Engineering, Pokfulam, Hong Kong Hong Kong
AB: The dynamic nature of groundwater storage has close linkage to land surface/vegetation/atmospheric processes, and thus weather and climate. However, the importance of groundwater as a hydrological and climatological variable has long been overlooked by the land surface modeling community. The availability of a multi-year comprehensive hydroclimatic dataset in Illinois has facilitated the characterization of the regional-scale hydroclimatology in Illinois by using the soil and atmospheric water balance approaches to quantify various water balance components including groundwater storage change. Based on the findings of the study, the roles that the regional-scale shallow unconfined aquifers play in the regional hydroclimatology can be summarized as follows: (1) Groundwater storage is a major water balance component whose storage change is as important as that of soil moisture at monthly or longer time scale. (2) The regional water table depth variation is highly correlated with streamflow in a strong nonlinear manner and explains 2/3 of the streamflow variance. (3) The unconfined aquifer amplifies the drought climatic anomalies and dissipates the flood anomalies, which results in the observed asymmetric response of the aquifers to the droughts and floods. (4) The unconfined aquifer supplies water to replenish the root-zone soil moisture, which helps maintain the observed high rate of summer evapotranspiration (~120 mm/month) in Illinois. The lessons learned from the Illinois study indicate that the storage change of the unconfined aquifer is comparable to that of soil moisture at the monthly and annual time scales, thus the representation of groundwater dynamics in land surface models (LSMs) is indispensable.
DE: 1829 Groundwater hydrology
DE: 1830 Groundwater/surface water interaction
DE: 1833 Hydroclimatology
SC: Hydrology [H]
MN: Fall Meeting 2005