Temporal and spatial variations of multivariate hot, dry and windy climate extremes in Northwest China

Abstract The simultaneous occurrence of extreme weather events such as high temperature, low humidity and strong wind speed can cause devastating impacts on the fragile environment and vulnerable ecosystem in arid Northwest China (NW). However, few studies investigate the multivariate compound hot, dry and windy extremes in NW. In this study, we investigate the temporal and spatial variations of the warm‐season trivariate hot, dry and windy (HDW) and bivariate hot and dry (HD), dry and windy (DW), hot and windy (HW) extremes in NW. From 1960 to 2019, we observed more compound HD, DW, HW and HDW days in the hyper‐arid Xinjiang and west Gansu in NW. Simultaneously, DW days, HW days and HDW days consistently declined at rates of −0.48, −0.88 and −0.42 day·10a−1, except for a discernible increasing rate of 0.56 day·10a−1 in HD days. Notably, trends in four multivariate compound extremes all experienced pronounced reversals from a declining to increasing trend in the 1990s. The higher probability of compound HD, DW and HW extremes contributed to a higher probability of HDW in Xinjiang province. Ultimately driven by the significantly rising temperature (0.21°C·10a−1, p < 0.01), four compound extremes suggested increased probability with the largest increase in compound HW probability from 1960–1989 to 1990–2019. Both the rising trends in the occurrence and the increased probability of four compound extremes highlight intense risks of compound extreme weather over NW in recent decades.