Contribution of Moisture Recycling to Water Availability in China

Abstract

Moisture recycling is an integral component of the hydrological cycle, enhancing regional water availability by returning evaporated moisture as precipitation either locally or downwind. In China, characterized by uneven water resource distribution and regional water scarcity, understanding moisture recycling dynamics is crucial for sustainable water management. Our study quantified the contribution of moisture recycling to precipitation and water availability across China and its sub-regions during 2000–2022 using an atmospheric moisture tracking model. Results revealed that 59% of China's evapotranspiration (ET) was recycled within the region, contributing 299 mm/year to precipitation and 98 mm/year to water availability. Distinct spatial patterns emerged, with the highest ET contribution to precipitation and water availability in subtropical Central and South China (477 mm/year precipitation; 210 mm/year water availability) and the Qinghai-Tibet Plateau (355 mm/year precipitation; 121 mm/year water availability). Water availability exchanges through moisture transport between sub-regions were quantified, with Northeast China and subtropical Central and South China being net water availability recipients of 31 and 67 billion m³/year, respectively. The remaining sub-regions were net exporters, with tropical South China and Northwest China experiencing the largest net exports, amounting to −40 and −30 billion m³/year, respectively. The study not only advances our understanding of the hydrological dynamics in China but also offers critical insights for sustainable water management practices aimed at mitigating challenges posed by water scarcity and climate change. It highlights the significance of integrating moisture recycling considerations into water resource management strategies to enhance resilience against hydroclimatic variabilities.