Spatially compound and local extreme precipitation events: behaviors and trends

Spatially compound extreme precipitation events can result in more severe impacts than individual extremes, posing significant challenges to both human and natural systems. Understanding their spatial distribution and trends is crucial for developing effective mitigation and adaptation strategies. In this study, we analyze multiple datasets, including reanalysis datasets (ERA-5, MERRA-2) and gridded networks derived from meteorological station data, to investigate long-term trends in precipitation over land and oceans at global, regional, and gridded scales. Using fixed thresholds, we assess the joint occurrence of extreme precipitation events and examine how these events change relative to temperature in different regions. 

Our findings show that the proportion of areas affected by spatially compound extreme precipitation events has increased significantly, particularly in tropical and coastal regions. Moreover, the growth trend in areas experiencing co-occurring extreme precipitation exceeds the trend observed at individual pixel scales, highlighting that focusing solely on pixel-scale changes underestimates the full extent of natural disasters caused by extreme precipitation. This synthesis underscores the escalating risks of compound climate extremes under global warming, driven by the complex interplay of joint precipitation occurrences.