Spatial-temporal Variations of Precipitation and Temperature in Tajikistan

This paper analyzes the spatial-temporal variations of precipitation and temperature using the data from46 meteorological stations from 1971 to 2013 based on the methods of EEMD,trends analysis and wavelet analysis.The results showed that: 1 In temporal variations,the annual precipitation and average temperature all have increasing trend,annual precipitation presented periodicities of 3 a,6 a,14 a and 27 a,and temperature presented periodicities of 3 a,7. 5 a,12-13 a and 32 a,respectively. 2 In spatial variations,the annual precipitation was significantly increased at the tendency rate of 15. 2 mm·( 10a)-1,and the distribution characteristics of average annual precipitation were gradually reduced from the central to the borders. The change trend of seasonal precipitation presented significantly difference,at the rate of-1. 7 mm·( 10a)-1( spring),1. 3 mm·( 10a)-1( summer),1. 1mm·( 10a)-1( autumn) and 4. 4 mm·( 10a)-1( winter),respectively. There was a decadal variation of precipitation: the annual precipitation was relatively low in the 1970 s,kept increasing in the 1980 s and 1990 s,and achieved the maximum in the 2000 s. The annual average temperature was significantly increased( average temperature tendency rate is 0. 26 ℃ ·( 10a)-1and the tendency rate gradually increased from the south to north. The seasonal average temperature all showed increasing trend and the order of increasing from stronger to weaker is winter,spring,autumn and summer. The temperature experienced a period of low-high-low-highin the decadal variations; the average temperature was relatively low in the 1970 s and 1990 s,relatively low in the eastern but high in the western in 1980 s,and relatively high in 2000 s,and the average temperature from 2000 to 2013( 0. 4-0. 7 ℃)is higher than that from 1971 to 2013. 3 The temperature and precipitation presents obvious resonance negative correlation in Tajikistan.