Estimating the Distribution of the XAJ Model Parameters in Upper Yangtze River Basin.

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Yuanhao Fang, Xingnan Zhang, Bo Qu, Dazhong Xia

Thursday 2 july 2015

12:51 - 12:54h 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

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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 estimated by the calibration which will need high technology and more uncertainty may be 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 gradient,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.