Analysis Of Characteristics Of Climate Change In Wuhan City From 1961-2012

In order to investigate the interannual and interdecadal and seasonal variation characteristics of the precipitation, average temperature, sunshine duration and average relative humidity in Wuhan city, analysis methods such as linear tendency analysis, moving average, variable coefficient, accumulative anomalies and Mann-Kendall mutation test are used in this paper, and based on these a simple analysis on the cause of climate change are made in Wuhan city, results are as follows:(1)The annual precipitation in Wuhan city in recent 52 years is fluctuating with a slightly increasing trend. Precipitation slightly increased in spring, summer and winter, while autumn was in a decrease trend. There was a rare rain period in 1960s and 1970s and a pluvial period in 1980s and 1990s. Both the annual precipitation and the average precipitation for four seasons have inter-decadal variations. At the same time, the anunual precipitation, spring precipitation and autumn precipitation don’t have mutation phenomenons, summer precipitation mutation occurred in 1979, and the winter precipitation mutation occurred in 1988 and lagged relatively.(2)The annual temperature in Wuhan city in recent 52 years shows a rising trend overall and the warm rate is higher than the whole country and Hubei province. The average temperature of four seasons shows a rising trend, which is the same to the annual temperature. Since the 1960s to 1980s, seasonal temperature and annual temperature didn’t changed too much, however, the temperature rose significantly since 1990s. Annual average temperature and autumn average temperature mutation both appeared in 1993, spring average temperature mutation occurred in 1994, summer average temperature mutation occurred in 1998, and winter average temperature mutation occurred in 1986.(3)Both annual sunshine duration and seasonal sunshine duration show a volatile downward trend in the whole 52 years,1960s to 1980s belongs to the period which have rich sunshine duration and period after 1980s belongs to fewer sunshine period. The decadal change of annual sunshine duration varied very definitely, during the whole research period, annual sunshine duration and seasonal average sunshine duration decreased in each decade, and coefficient of variation also have inter-decadal variations. Annual, spring and summer sunshine duration both haven’t mutation points, autumn sunshine duration mutation took place in 2007, winter sunshine duration mutation occurred in 1984.(4)Both annual and seasonal average relative humidity show a volatile downward trend in the whole 52 years, the downward trend was significant and drying characteristics was obvious especially after 1990s. There’s a downward trend between each decadal average relative humidity, the coefficient of variation of them keeps rising as a whole, and coefficient of variation for seasonal average relative humidity also varies in different decades. Annual, spring and winter average relative humidity didn’t have mutation points, summer average relative humidity mutation occured in 1998, autumn average relative humidity occured in 1978 and 1987.(5)The annual precipitation days shows a downward trend in the whole 52 years, while spring and autumn precipitation days changed as same as annual trend, the summer and winter increased slightly. The decadal average precipitation days in Wuhan city varied in 114.6d to 128.9d, the maxmum was in 1980s, the least was in the early of this century; precipitation days of four seasons and coefficient of variation are also different. The annual precipitation days mutation occured in 1998, spring precipitation days has three mutations points in 1980s, they are 1981,1985 and 1988, autumn precipitation days has several mutations years since 1960s to 1970s. Summer and winter precipitation days have no mutations points.(6)The climate change in Wuhan city was influenced by global climate change, and also related to its particular geographic feature, more importantly, the urban development has caused a significant impact on it. These factors lead to the rising of annual precipitation and average temperature, and also lead to the downward of annual sunshine duration and average relative humidity.