Spatiotemporal variations of surface water and its response to climate change in global arid regions during 2000–2020

Surface water plays an essential role in the ecohydrological cycle, especially in water-scarce regions. Changes in surface water restrict social, economic, and agricultural development. However, the patterns and underlying causes of surface water changes over varying frequencies in global arid regions remain unclear. Thus, this study investigated the changes in surface water and the underlying causes using the trend analysis and Spearman correlation coefficient on the basis of multi-source remote sensing and climate datasets across global arid regions during 2000–2020. The surface water was divided into temporary surface water (TSW), seasonal surface water (SSW), and permanent surface water (PSW) by calculating the surface water inundation frequency. Considering that surface water may be influenced by precipitation in the upper basins, we analyzed the response of surface water area to climatic factors at the basin scale. The area of all surface water (ASW) increased dramatically in global arid regions from 2000 to 2020, increasing from 61.88×10 4 to 67.40×10 4 km 2 ; however, this increase was accompanied by a decrease in surface water inundation frequency. TSW increased by 55.46% relative to its area in 2000, with a net change rate of 3284.00 km 2 /a. Changes in surface water were predominantly observed in the Kyzylkum Desert in Central Asia, the Thar Desert in southwestern Asia, and the deserts in Oceania. Precipitation had a significant effect on SSW and TSW at the basin scale. The correlation between precipitation and SSW area can reach 0.808 in the Indus River Basin of the Thar Desert ( P <0.01). The findings provide a more comprehensive understanding of surface water variability in global arid regions, carrying significant practical implications for the scientific management of surface water at different frequencies.