Land-surface influences on precipitation characteristics in the wet Asian monsoon regions: A review integrating high-resolution satellite observations and convection-permitting climate modeling

This review examines how land-surface conditions influence precipitation characteristics across the Asian monsoon area, with a particular focus on “the wet Asian monsoon regions” in parts of Southeast, South, and East Asia. In these wet regions, the role of land–atmosphere interactions in modulating precipitation has long been considered minor, whereas land-surface effects have been more extensively investigated in semi-arid regions. Against this background, we reassess how land–surface conditions influence precipitation in monsoon climates by organizing the evidence within a physical hierarchy that highlights cross-scale linkages between the seasonal march of the monsoon, the diurnal precipitation cycle, and climate variability. Within this hierarchy, the Asian monsoon is characterized by a contrast between rainy and dry seasons, and its precipitation exhibits a robust diurnal cycle, one of the key processes examined in this review. Whereas many previous studies have often highlighted precipitation amounts and extremes, this review emphasizes more fundamental aspects such as precipitation intensity and frequency. These precipitation characteristics, observed globally by high-resolution satellite precipitation radars, have been extensively analyzed over the past two decades and are now more realistically simulated by convection-permitting climate models. This improved reproducibility enables process-oriented assessments of the sensitivity of precipitation characteristics to land-surface conditions and reveals that issues in convection-permitting climate modeling are not only technical but also scientific, providing important insights into the physical mechanisms of precipitation. Finally, we summarize the status and future directions of observational projects, which offer opportunities to integrate observational and modeling approaches and to advance understanding of precipitation characteristics of the Asian monsoon.