Global precipitation system scale increased from 2001 to 2020

Abstract

How precipitation responds to global warming has drawn much interest from the scientific community. However, as one of the important properties of precipitation, changes in the precipitation system scale have rarely been studied. The latest retrospective merged satellite precipitation product has provided a great opportunity to investigate quasi-global precipitation system scale changes. This study uses the Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) data during 2001–2020 to investigate quasi-global precipitation system scale changes. Our results indicate that, generally, quasi-global precipitation system scales exhibit a significant increasing trend, which is more significant in winter and spring than that in summer and autumn over both hemispheres. The scale of nearly all precipitation systems over land regions has increased over the last two decades. In oceanic regions, precipitation system scales increase over tropical oceans but decrease over subtropical oceans. Medium-scale precipitation systems (100–1000 km) significantly increase in scale and decrease in frequency, while large-scale precipitation systems significantly increase in frequency, which both lead to a quasi-global increase in the precipitation system scale. Diagnostic investigation based on atmospheric analysis reveals that an increase in atmospheric stability tends to suppress local convective precipitation, while an increase in the total column water vapor could help maintain and enhance precipitation system scale, which jointly contribute to quasi-global precipitation system scale increase.