Likelihood of concurrent climate extremes and variations over China

Abstract

Extreme climate events such as droughts and heat waves exert strong impacts on ecosystems and human well-being. Estimations of the risks of climate extremes typically focus on one variable in isolation. In this study, we present a method to examine the likelihood of concurrent extreme temperature and precipitation modes at the interannual scale, including compound cool/dry and cool/wet events during the cold season as well as compound hot/dry and hot/wet events during the warm season. A comparison of changes in the likelihood of such joint climate extremes was then conducted between the first (1961-1987) and second (1988-2014) halves of the full observed records. Our findings indicate a decrease in the occurrence probability for most concurrent modes over much of China, despite positive shifts found over southwestern and northeastern parts of China for the compound hot/dry events in the warm season. We further examined changes in likelihood related to these four compound climate extremes between the historical observed period (1961-2014) and the future period (2021-2080) based on climate model simulations with the RCP8.5 scenario. Our results show widespread increases in the occurrence probability for wintertime cool/dry and summertime hot/dry and hot/wet events over most parts of China but with different magnitudes, while much of China may experience declining likelihood of the wintertime cool/wet extremes in the future.