The Driving Processes of Concurrent Hot and Dry Extreme Events in China

Abstract Subseasonal heatwave-driven concurrent hot and dry extreme events (HDEs) can cause substantial damage to crops, hence lives livelihoods. However, the physical processes that lead these devastating are not well understood. Based on observations reanalysis data for 1979–2016 over China, we show HDEs occur preferentially central eastern China (CEC) southern (SC), with a maximum of three per year along Yangtze Valley. The probability longer-lived potentially more damaging is larger in SC than CEC. Over key factors HDEs—positive anomalies surface air temperature evapotranspiration, negative soil moisture—begin two pentads before maximizing at peak HDEs. These south positive height anomaly 200 hPa, associated large-scale subsidence anomaly. CEC similar those SC, but begin one pentad peak. HDE frequency strongly related Silk Road pattern boreal summer intraseasonal oscillation. Positive phases suppressed oscillation increasing by about 35%–54% relative climatological mean. Understanding effects subseasonal seasonal atmospheric circulation variability, such as oscillation, important improve predictions China.