Spatially varying effect of soil moisture-atmosphere feedback on spring streamflow under future warming in China

Abstract

Abstract Soil moisture–atmosphere feedback (SAF) is expected to accelerate warming in the future, but its influences on the terrestrial water cycle over non-traditional hotspots of land–atmosphere coupling (e.g., East Asia) remains elusive due to strong heterogeneity and uncertainties at model grid scales. Here we show robust evidence of the integral effects of SAF on streamflow under future warming across major river basins in China. Based on high-resolution hydrological modelings driven by CMIP6 simulations with/without land–atmosphere coupling, SAF is projected to significantly increase spring streamflow by 28–58% in mid-latitude China, but decrease it by 12–48% in other regions. Such contrary effects are attributed to the soil moisture-precipitation interaction, which causes spatially opposite changes in precipitation through thermodynamic (e.g., ascending/descending vertical motions) and thermal (e.g., weakened meridional water vapor transport) atmospheric adjustments. Our result highlights the importance of SAF in altering freshwater resources even in locations not typically considered to be SAF hotspots.