Application of Distributed Hydrological Model in the Asian Monsoon Tropic Region with a Perspective of Coupling with Atmospheric Models

抄録

Prediction of variations of global and regional hydrological cycles and their response to changes of climate and environment is an important topic. For this purpose, improving the ability of hydrological models has been in the direction of ever-increasing spatial scales. Owing to the highly nonlinear nature of hydrological processes and the high degree of variability of the spatial heterogeneity, distributed representation of spatial information and physical description of hydrological processes are necessary. It is also important to incorporate the regulation of water by infrastructures (e.g., large reservoirs) with the hydrological modeling to verify direct human influence on water resources. The GBHM (geomorphology based hydrological model) employs a flow interval-hillslope discretization scheme in the representation of hydrological processes using catchment geomorphologic properties. The GBHM can represent the characteristics of catchment landform properly and is flexible enough to describe other spatial variability, such as land cover and soil type. In the present study, GBHM was applied to the Chao Phraya basin in Thailand, in which the GEWEX Asian Monsoon Experiment in a tropic region (GAME-T) has been carried out since 1995, for investigating the applicability of this model to regional scale. The hydrological simulation has run from 1994 through 1995 with a drainage area of 110, 000 km². The reservoir (Bhumibol and Sirikit) operations were incorporated with the hydrological modeling. The simulated hydrographs at 16 locations, including two reservoirs, were compared with the river flow observations for evaluation of the model performance. The possibility of coupling GBHM with the atmospheric model is discussed in the paper.