Effect of Climate Change on NPP of Natural Vegetation in Xinjiang

Based on the temperature and precipitation data observed by 101 meteorological stations in Xinjiang during the period of 1961-2008,the NPP values are calculated using Zhou Guangsheng and Zhang Xinshi model,and the spatiotemporal variation of temperature,precipitation,NPP and their relations are analyzed using linear regression,Morlet wavelet analysis,Mann-Kendall abrupt test,correlation analysis and Kriging spatial interpolation method. The response of NPP to the change of annual temperature and precipitation in the future is discussed. The main results are as follows:( 1) The spatial distribution of temperature and precipitation was quite different from different regions of Xinjiang,as a whole,the temperature in south Xinjiang was higher than that in north Xinjiang,higher in the basins ( valleys) than that in the mountainous areas. Precipitation in the mountainous areas was higher than that in the basins ( valleys) ,higher in the western and northern parts of Xinjiang than that in the eastern and southern parts; ( 2) Climate became warmer and wetter in recent 48 years in Xinjiang,and the annual mean temperature,precipitation had the discontinuity ascension in 1972 and 1978,but the change rate is different in every areas,in general,the climate warming rate was large in northern Xinjiang than in southern Xinjiang and mountain area,precipitation increasing rate was large in northern Xinjiang and mountain area than in southern Xinjiang. The annual mean temperature and precipitation has had quasi -4 a,9 a,11 a,16 a and 23 a cyclical changes; ( 3) By the comprehensive affected of temperature and precipitation,the NPP is large in Tianshan mountain area than in northern and southern Xinjiang,and the NPP is increasing by the rate of 0. 118 t/( hm2·10 a) in recent 48 and there was mutability increase in 1978,and it exist 3 -4 a,6 -8 a,11 a and 16 a cyclical changes; ( 4) The result of pre-diction demonstrates that the wetting climate change will improve the natural vegetation NPP in Xinjiang in the fu-ture,but climate warming will have unfavorable effect on NPP. Holistic,under the precondition of other invariable factors,the NPP will be increased by 20% once the annual precipitation is increased by 10% ,and the NPP will be decreased by 4% -6% once the annual temperature is increased by 1 ℃. However,the response of NPP to climate change is different from different regions of Xinjiang.