Abstract: In this paper,the variations of 10 kinds of extreme temperature indices were analyzed based on the daily minimum and maximum temperatures at Turpan Weather Station during the period of 1952-2013 by using the linear method,moving average,Mann-Kendall test,Morlert wavelet analysis and principal component analysis.The results are as follows:① Six indices including the maximum and minimum air temperatures and the summer days,hot and warm nights and warm days were all in an increase trend with rates of 0.07 ℃·(10a)^-1,1.31 ℃·(10a)^-1,2.15 d·(10a)^-1,5.15 d·(10a)^-1,5.65 d·(10a)^-1 and 2.04 d·(10a)^-1,while the four indices including the ice days,frost days,cold nights and cold days were all in a decrease trend with rates of -0.61 d·(10a)^-1,-5.49 d·(10a)^-1,-6.09 d·(10a)^-1 and -2.12 d·(10a)^-1,respectively; ② The results of mutation analysis showed that there was no mutation of extreme maximum temperature,and the mutation of extreme minimum temperature occurred in 1984,while the mutations of absolute index occurred in the end 1980s,early 1990s and early 21st century,and the mutations of relative index happened in the end 1990s and the early 21st century; ③ There were about 28-29 a main recycles of maximum and minimum air temperatures,and about 12-29 a main recycles of cold and warm nights with high variable ratios;④ The results of principal component analysis showed that the first principal component accounted for 50.63% of the variance contribution rate,and the minimum air temperature,hot nights,frost days,cold nights,warm nights,cold days and cold nights affected significantly by the temperature change in Turpan.In general,both the highest and lowest temperatures in Turpan were in an increase trend,the latter increased more significantly than the former.The warming index increased but the cold index decreased significantly,the temperature in Turpan was in an increase trend,the change trend of extreme temperature in Turpan was consistent with the that in whole China and Xinjiang,the rangeabilities of summer days,frost days and hot nights were higher than those in whole Xinjiang and the extreme temperature index in China.The Arctic Oscillation (AO) and urbanization process were the main factors affecting the extreme temperature anomaly in Turpan,the hot and cold fluctuations were mainly caused by the extreme temperature events,which had an impact on the crop growth and yield,regional development,economic structure,and plant diseases and insect pests as well as the human activities and social sustainable development.The results could provide the theoretical basis for the sustainable development of local agriculture and for preventing meteorological disasters in Turpan.Because of the shortage of research sites,in this paper the change of extreme temperature indexes was analyzed just from the time scale rather than the spatial scale.

Key words: extreme temperature index, variation trend, Mann-Kendall test, Morlert wavelet analysis, Turpan City, Xinjiang