A parameterization scheme of distributed hydrological model to reflect the elevation influences in the Jinshajiang River basin.

Yangwen Jia, Jiajia Liu, Cunwen Niu, Zuhao Zhou, Hao Wang, Jiasheng Jia

Thursday 2 july 2015

12:57 - 13:00h at Central America (level 0)

Themes: (T) Water resources and hydro informatics (WRHI), (ST) Catchment hydrology, Poster pitches

Parallel session: Poster pitches: 11H. WRHI - Catchment

To reflect the spatial heterogeneity of the hydrological parameters, the parameterization scheme of most distributed hydrological models is realized by subdividing a study area into numerous computational units (i.e., hydrological response units, HRU) in terms of land cover, soil type and sub-catchment etc., in each of which uniform parameter values are assumed. This kind of parameterization is a planar parameterization scheme just considering the heterogeneity in horizontal direction, without reflection of the heterogeneity impacts at vertical direction. However, in high mountain areas, vegetation ecosystem, hydro-meteorology, soil and topography etc. are highly influenced by elevation. In other word, elevation is a vital factor influencing the parameterization. Thus, a new three-dimensional parameterization scheme is proposed to reflect the elevation influences, i.e., the value of height and other correlative factors are used to estimate the value of hydrological parameters, such as depression depth of land surface, leaf area index (LAI), slope, soil thickness and other parameters. An application is performed to test the effect of the three-dimensional parameterization scheme, in which the distributed hydrological model named water and energy transfer processes in large river basins (WEP-L) is adopted for the improvement, and the Jinshajiang River Basin (with an elevation difference of 5100m between the river source and the river outlet) in the southwest of China is taken as the study area. The application results indicate that the newly-suggested parameterization scheme can rationally depict the vertical heterogeneity of hydrological parameters, and it also obviously improved the simulation results of river flows and evapotranspiration by a comparison with the original model.