Spatio-temporal variation of extreme temperature in different climatic regions of the world and its large-scale atmospheric circulation mechanism

Under global warming, the frequent occurrence of extreme temperature events (ETE) poses a serious threat to ecological security and sustainable socio-economic development. Understanding the spatial and temporal variation of extreme temperatures and their driving factors across multiple climate regions is a core scientific question in climate research. Using ERA5 reanalysis data and 88 atmospheric circulation indices, this study applies the Köppen-Geiger climate classification system to examine the evolution of ETE across 13 global land climate zones from 1951 to 2024 and assesses their relationship with atmospheric circulation through a multi-method framework combining trend analysis, correlation testing, and the Geodetector model. The results showed: (1) extreme warm events increased in most regions, whereas extreme cold events declined. (2) Spatial heterogeneity in ETE was evident. The cold spell duration index (CSDI) increased across large areas of Eurasia. The decline rates of frost days (FD) and icing days (ID) in high-latitude climate zones exceeded those in other regions. The increasing rates of extreme temperature value indices (TNn, TNx, TXn, and TXx) were higher in mid-high-latitude climate zones than those in low-latitude region. (3) The Northern Hemisphere Subtropical High Area Index (NHSHA), North American Polar Vortex Area Index (NAPVA), Antarctic Oscillation Index (AAO), and Asian Polar Vortex Intensity Index (APVI) exerted significant effects on global extreme temperature changes. (4) Interactions among atmospheric circulation factors produced nonlinear enhancement or two-factor enhancement effects on ETE. The explanatory power of paired atmospheric circulation variables (q=0.26–0.84) was 3%–67% higher than that of single variables (q=0.06–0.79). This study strengthens the understanding of extreme temperature dynamics from a multi-scale feedback perspective and provides a scientific basis for developing region-specific climate adaptation strategies.