Abstract:Based on the data series of the annual mean, highest, and lowest temperatures and annual day numbers for 8 kinds of extreme weather events from 1951 to 2007 in Wuhan City, the trend and the relationship between annual mean temperatures and the day numbers with extreme weather are analyzed. By introducing the Granger causality detection algorithm, the relationship between climatic warming and extreme weather events is studied. The results show that: (1) the increase rate of annual mean lowest temperature in Wuhan in recent 57 years is 0.45 ℃/10a, which is much higher than that of the annual mean highest temperature of 0.19 ℃/10a. It indicates that the climatic warming is mainly caused by nighttime temperature increasing. (2) The frequency of high temperature and muggy weather events increased with year. The increasing rate of muggy weather is 2.8 d/10a and more evident than high temperature. The frequency of thunderstorm, snow, low temperature, gale, and fog decreased evidently with year. The decrease rates of thunderstorm, fog and low temperature are much larger and are 3.0, 4.0 and 2.1 d/10a respectively. The decrease rates of gale and snow events are 1.8 and 1.5 d/10a. The fluctuation of rainstorm events is small. (3) The annual mean temperature is highly correlated with the extreme weather events at time periods 0 years (concurrent) or ±(1-2) years (leading or leg). (4) The Granger causality detection results show that the climatic warming is the causes for the muggy weather increasing, snow event decreasing, and the gale and low temperature decreasing. The existence of causality is very valuable for the forecast of extreme weather events.