Impact of Land Use and Cover Change in the Semi-arid Regions of China on the Temperature in the Early 21st Century

The impacts of land use and cover change (LUCC) in the early 21st century on the temperature in the semi-arid regions of China were simulated using the WRF model. Determining the contribution rate of regional-scale LUCC on climate warming can improve and deepen our understanding of climate change attribution, which can in turn provide an important scientific basis for climate warming mitigation through the regulation of human activity. The simulated results show that the three main types of LUCC phenomena in the semi-arid regions, including farmland expansion, afforestation, and grassland restoration, all appear to have had negative effects on local-scale surface air temperature. Farmland expansion resulted in a decrease in local annual mean temperature by 0.11℃, with the summer and winter values being 0.39℃ and 0.06℃, respectively. Afforestation reduced local annual mean temperature by 0.33℃, with winter witnessing stronger cooling than summer (0.24℃ and 0.15℃, respectively). Grassland restoration resulted in a decrease in local annual mean temperature by 0.41℃, with the values for summer and winter being 0.58℃ and 0.51℃, respectively. The influence of LUCC on the minimum temperature was more than the maximum temperature; moreover, the diurnal temperature range increased, mainly due to the decrease in minimum temperature. The local temperature changes caused by LUCC were comparable with the grid-scale background temperature changes, while the impact of LUCC on the regional average temperature was negligible. On the one hand, the share of LUCC grids was small; while on the other hand, the positive and negative effects in the process of regional averaging offset each other. Therefore, the influence of actual LUCC on temperature was mainly limited to the local scale.