Changes in regional wet heatwave in Eurasia during summer (1979–2017)

Abstract Wet heatwaves can have more impact on human health than hot dry heatwaves. However, changes in these received little scientific attention. Using the ECMWF Reanalysis v5 reanalysis dataset, wet-bulb temperatures ( T w ) were used to investigate spatial-temporal variation of wet Eurasia for 1979–2017. defined as three day or longer periods when was above 90th percentile summer distribution and characterized by amplitude, duration frequency. Maximum values close 31 °C, occur Indus–Ganges plain, lower Yangtze valley, coasts Persian Gulf Red Sea. Significant positive trends frequency amplitude occurred over most though with regional variations. Changes heatwave (HWA) are largely driven mean . For a whole, increases temperature contribute six times relative humidity (RH) HWA. strong dependence climatological RH an increase 1% causing 0.2 °C arid regions, only increasing 0.1 humid regions. During Europe, parts Tibet, India, East Asia Arabian Peninsula both , dominant driver. part Russia, weak is mainly caused temperature. In Mediterranean Central Asia, has fallen reducing from general warming.