HR: 14:50h
AN: H23F-05    [Abstracts]
TI: Timescales of Land Surface Hydrology
AU: * Wang, A
EM: ahwang@atmo.arizona.edu
AF: Department of Atmospheric Sciences, The University of Arizona, 1118 E. 4th St., P.O. Box 210081, Tucson, AZ 85721 United States
AU: Zeng, X
EM: zeng@atmo.arizona.edu
AF: Department of Atmospheric Sciences, The University of Arizona, 1118 E. 4th St., P.O. Box 210081, Tucson, AZ 85721 United States
AB: The hydrological cycle between the atmosphere, vegetation, and soil is important but the temporal structure and persistence of water stored in the vegetation and soil are complicated. In our recent work (Wang et al. 2004), we have investigated the temporal variation and vertical structures of vegetation and soil in response to precipitation forcing. A simplified interactive model has been developed that includes the basic physical processes of land surface hydrology. A theoretical framework has also been developed to analyze the timescales of land surface hydrology in both the one-layer bucket model and the current three-layer model. It is found that different water reservoirs of the vegetation-soil system have different timescales. Precipitation forcing is mainly concentrated on short timescales, but it can cause long timescale disturbances in the soil moisture of root zone. Furthermore, this timescale increases with increasing soil depth and is also strongly influenced by soil properties. It is also found that the inherent timescale determined by the ratio of the field capacity to the potential evapotranspiration is only a first-order approximation for the response timescale of each land surface component. Furthermore, comparison of this three-layer model with the one-layer bucket model indicates that their timescales of evapotranspiration are quite different although those of soil moisture itself do not differ much. This suggests the need to consider the vertical structure in land surface hydrology reservoirs and in climate study. References: Wang, A., and coauthors, Timescales of land surface hydrology, J. Hydromet., Submitted, 2004.
DE: 3322 Land/atmosphere interactions
DE: 3309 Climatology (1620)
DE: 1833 Hydroclimatology
DE: 1866 Soil moisture
DE: 1620 Climate dynamics (3309)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting