Impacts of meteorological factors and land use pattern on hydrological elements in a semi-arid basin

The allocation of water resources to meet both human wellbeing and environmental requirements is a critical challenge in a semi-arid landscape. Hydrological models are widely used to understand the influence mechanism of hydrological elements, which is helpful for optimizing water resources management. However, the spatial heterogeneity of hydrological dynamics has been largely omitted in prior studies, partly because it's difficult to correctly simulate the spatial distributions of hydrological elements due to roughly representing the surface biophysical parameters in the hydrological model. In this study, the Distributed Hydrological Soil Vegetation Model (DHSVM) was incorporated with the high-resolution remotely sensed leaf area index (LAI) data in a semiarid basin, located in the upstream of the Xar Moron River Basin, to explore the impacts of meteorological factors (i.e., air temperature, wind speed, relative humidity, shortwave radiation, and precipitation) and LAI on hydrological processes of forests, grasslands, and farmlands. Our results show that the spatial distribution of LAI slightly improves the accuracy of streamflow simulations and significantly promotes the model performance of spatial hydrological element simulations. For the area in study, precipitation, LAI, and relative humidity are the three major influential factors in the forest hydrological dynamics. The hydrological elements of grasslands and farmlands are mainly affected by shortwave radiation, relative humidity, air temperature, and LAI. Compared with grasslands and farmlands, LAI has greater negative influence on forest water availability. To mitigate the negative effects of drying and warming climate and promote ecosystems sustainability, the forest area should be converted into grassland while the native grassland should be maintained for soil water conservation.