Abstract: In arid and semi-arid regions, rainfall infiltration is the main source of groundwater recharge, and studying its recharge
mechanism is of great significance for the rational development and utilization of groundwater resources in the regions. Nowadays, the global climate warming is increasingly intensifying, causing changes in the spatiotemporal variability of rainfall and therefore groundwater recharge. However, the impact of climate warming on groundwater recharge in arid and semi-arid regions is still unclear. This study chose Yulin City, Shaanxi Province as the study area. An observation station was constructed to record meteorological data and soil moisture data at several depths. A one-dimensional unsaturated water flow model was established using HYDRUS-1D to simulate infiltration process and calculate potential groundwater recharge. The model was calibrated and validated with the observed soil moisture data. Based on the validated model, the mechanism of groundwater recharge in the study area under four climate warming scenarios, ssp1-2.6, ssp2-4.5, ssp3-7.0, ssp5-8.5, was systematically studied, and the potential groundwater recharge trend was predicted. Results show that, (1) The impact of climate warming on rainfall in the study area is relatively minor, but its impact on air temperature is more significant. The rainfall in the study area will slowly increase, and the trend of air temperature changes will vary with different climate warming scenarios; (2) The potential groundwater recharge will reduce in all scenarios except ssp1-2.6, the weakest climate warming scenario; (3) The potential groundwater recharge in the study area is less affected by the change in the rainfall, and more affected by the change in evapotranspiration intensity.

Key words: arid and semi-arid regions, potential groundwater recharge, climate warming, numerical model