Spatio-temporal variations of extreme precipitation and its response to atmospheric circulation in different climate zones over the global land from 1951 to 2020

Under the combined influence of climate change and human activities, extreme precipitation events (EPEs) occur frequently, posing a severe threat to ecological security. Revealing the spatio-temporal differentiation laws of EPEs in multiple climate zones and these driving mechanisms is one of the core scientific issues in responding to climate change. Based on Fifth generation of ECMWF atmospheric reanalyses for climate(ERA5)data and 88 kinds of atmospheric circulation indices, a multi-method coupling framework was constructed by integrating trend analysis, correlation test and geographic detector model, for analyzing the evolution characteristics of EPEs in 13 climate zones around the world from 1951 to 2020 and their driving mechanisms of atmospheric circulation. Results showed that: (1) Consecutive dry days (CDD), consecutive wet days (CWD), and moderate rainy days (R10) in more than 50% of the global land all presented a downward trend. Annual total precipitation (PRCPTOT), the number of heavy rain days (R20), the heavy precipitation(R95p), the extremely heavy precipitation(R99p), the maximum daily precipitation (RX1day), and the 5-day maximum precipitation (RX5day) in more than 50% of the global land all presented an upward trend. (2) Spatial heterogeneity characteristics were significant. CDD showed an upward trend in a few regions of Asia and Africa, and PRCPTOT, R10, R20, R95p, R99p, RX1day and RX5day showed an upward trend in low latitudes, especially in tropical rainforest climate regions.(3)Northern Hemisphere Subtropical High Area Index (NHSHAI), Atlantic-European Polar Vortex Intensity Index (APVII), Pacific Polar Vortex Area Index (PPVAI) and East Pacific 850mb Trade Wind Index (EPTWI) have a wide impact on EPE changes in the global climate region. (4) Interactions between atmospheric circulation factors can lead to nonlinear amplification or two-factor enhancement effects on changes in extreme precipitation events. The synergistic explanatory power of two factors (q = 0.30–0.80) is 3%–68% greater than that of any single factor (q = 0.03–0.60). This study deepens the understanding of EPE dynamics from the perspective of multi-scale mutual feedback mechanisms, providing a scientific basis for formulating regional differentiated climate adaptation strategies.