Temporal And Spatial Distribution Of Humid Index Of Jilin Province In Recent 50 Years

Climate variation, including the distribution, the time evolution characteristics, cycles and abrupt changes of precipitation and temperature and the wet and dry climate changes of Jilin province in recent 50 years has been analyzed based on the daily precipitation and temperature data from 1958 to 2007 of 22 stations in Jilin Province by using statistical diagnosis such as the trend coefficient,EOF,REOF, wavelet transform, MK mutation testing etc..It is found that :1)Precipitation decreased gradually from southeast to northwest,it increased in the southeast and decreased in the northwest, precipitation increased in summer and autumn, declined in spring and winter it showed overall consistency, reversity in north and south ,east and west.2)Precipitation increased in the past 50 years, the climate trend rate is 10.5mm/10a, 2-3 years,5-6 years, 11-years cycles was shown, mutation was in 1983. mutations of four seasons occoured in the order of spring, summer , autumn and winter.3)The average temperature was higher in the southern than in the northern, and significantly increased in the last 50 years; the temperature increased allover Jilin Province from outside to inside.4)Climate trend rate of temperature was 0.33℃/ 10a, cycles were 3-5years and 10 years, mutation was in 1992. The temperature of winter increased most significantly, mutations of four seasons occoured in the order of spring, winter, summer and autumn.5)Distribution of potential evaporation roughly decreased from south to north, and from east to west, the annual average was 662mm. Potential evaporation was upward all but the trend coefficient was different in different parts and irregular distribution.6)Potential evaporation was upward among the 640-680mm ,the climate trend rate was 7.74mm/10a, cycle of 3-5 and 10 years were the most obvious, mutation occured in 1993.7)The humid index of Jilin Province increased unobviousiy, annual variation was relatively large the most humid year was 1986,the most dry year wsa 1958, the cycle was 3-5 and 10 years, mutations occurred between1979 and 1980.8)It was constantly changing that the boundary of humid and dry areas of Jilin before and after1980, wet area extented from the southeast to the northeast, north,and northwest to reach the middle area of Jilin Province at last, the largest mobile diameter was about 100km, the southern boundary of semi-arid-humid areas of the two periods dided significantly move, the northern moved to east a little after 1980, the maximum distance was about 15km,in a word the humid zone continued expanding and becoming more humid, semi-Arid area slightly expanded and becomed more dried .