Author(s): Xing-Nan Zhang; Yuan-Hao Fang; Bo Qu; Da-Zhong Xia
Linked Author(s): Xingnan Zhang
Keywords: Xin’anjiang model; Parameters estimation; GIS; Underlying surface indices
Abstract: Hydrological models are essential in assessing hydrological processes at both hillslope and watershed scale. The Xin’anjiang (XAJ) Model is a conceptually-based model which was developed on the basis of conception of hillslope hydrology. Although processes like evapotranspiration, runoff yield and routing are represented by generalization rather than physically-based partial differential equations, several parameters of the model have rigid physical definitions which can be estimated by characteristics of the watershed. Due to the lack of measurement and data, however, these parameters were mainly estimated by calibration which will need high technology and more uncertainty may been introduced into the model. Recently, benefiting from GIS and RS, data have been significantly improved in both the quantity and the quality. In this paper, the indices of the underlying surface of a watershed were derived firstly (e. g. the slope and aspect of hillside, roughness, soil, vegetation, etc. ), these indices were then employed to establish the relationships with the parameters on the basis of the physical definitions or the statistical analysis purely. By use of this approach, the overall performance of the XAJ model was much more robust than that of the calibration, and more suitable to be used in ungauged catchments.