Climate Evolution Characteristics of Eastern Tibetan Plateau for the Last 55 Years

According to the climate data from 1958 to 2012 of 50 meteorological offices in eastern Tibetan Plateau area,Using climate trend rate,cumulative departure method,Mann-Kendall mutation test,Morlet wavelet,Inverse distance weighting methods to analyze the trend,characteristics and spatial distribution of monthly average air temperature,precipitation,sunshine hours and wind speed in eastern Tibetan Plateau in recent 55 years. Results indicates that: 1 The annual average air temperature showed a significant rising trend at the rate of 0. 25 ℃ ·( 10a)-1,annual total precipitation showed a significant rising trend at the rate of 6. 24 mm·( 10a)-1,annual sunshine hours showed a significant decreasing trend at the rate of-15. 24( 10a)-1,average wind speed showed a significant decreasing trend at the rate of-0. 06 m·s-1·( 10a)-1in eastern Tibetan Plateau in recent 55 years.On the whole,the eastern Tibetan Plateau climate present a clear trend of warm-wet,but the direction and the rate of the regional climate change has obvious difference affected by the different natural environment. For example,the climate in southern Gansu,presents an obvious warm and dry phenomenon. 2 Annual average air temperature occurred significant elevated in 1993 in eastern Tibetan Plateau,annual precipitation occurred significant rising in1984,annual average wind speed and sunshine time occurred significant decrescence in 1992 and 2001,respectively. 3 The first primary change cycle of annual average air temperature,precipitation,sunshine hours and wind speed is about 13 years. The climate change cycle of the eastern Tibetan Plateau has a strong consistency. It is of great help to the predict of climate change in eastern Tibetan Plateau. 4 In eastern Tibetan Plateau,the average air temperature showed a increase trend gradually from northwest to southeast in space,its changing trend is given priority to increasing. Annual precipitation showed a increase trend gradually from northwest to southeast,its changing trend is given priority to increasing. Annual sunshine hours showed a decreasing trend gradually from northwest to southeast,its changing trend is given priority to decreasing. The spatial change trend of average wind speed is complex relatively,the change tendency is given priority to decreasing,but its spatial distribution is not obvious.