Spatio-temporal Variations Of Temperature And Precipitation In Lop Nor Region During 1957~2017

The unique location and fragile habitat of the Lop Nor region make it sensitive to climate change.Environmental changes of the Lop Nor region not only directly affect on its own ecological environment,but also have an impact on the whole country or on the arid region of Asia.Therefore,the study of climate change in Lop Nor region can reflect the climate and environmental changes in the arid area to a certain extent,and it has far-reaching significance for protecting its fragile and sensitive ecological environment and scientific climate prediction.Based on the daily temperature and precipitation data of six meteorological stations around Lop Nor from 1957 to 2017,the spatial-temporal variation characteristics of temperature and precipitation in Lop Nor area have been analyzed by used of Linear regression,Polynomial fitting method,Moving average,Anomaly and Accumulated variance analysis,T-test and IDW.The main conclusions are as follows:(1)The temperature and precipitation in the Lop Nor region have shown an upward trend,and the annual mean temperature in the Lop Nor area increased slightly with the rate of 0.27°C/10 a.The annual precipitation is generally increasing with the rate of 2.04mm/10 a.The seasonal average temperature in this region had an evident uptrend,and the trend is most significant in winter,while appeared to have a sign of winter warm and cool summer.Spring precipitation contributes the most part to the annual precipitation.The chronological changes including the annual mean temperature and annual precipitation are an obvious increasing trend with the large rate of chronology in the period we studied,while sharp increase occurred since the 21 st Century.(2)Spatial variation characteristics of temperature and precipitation are that the spatial variation of temperature in Lop Nor area is the more significant: in the Turpan Basin is a high-value area,and in the Altun Mountains are the low-value areas;the significant temperature changes are mainly occurred in the Cheerchen River and the Peacock River Basin;after entering the 21 st Century,the temperature shows a trend of warming and spatial differentiation.(3)There is a significant difference in precipitation space.The annual precipitation has a high value center that is the Peacock River and the Cheerchen River Basin and a low-value center-Turpan area;the significant changes of precipitation are in the Kongque River and the Cheerchen River Basin;The annual precipitation changes most prominently occurred in the 1980 s and early 21 st Century;the rainy season precipitation is concentrated in the 1990 s and the early 21 st Century.(4)The extreme highest temperature and the lowest temperature both showed an upward trend,and the average rate of increase was 0.26 °C/10 a and 0.49 °C/10 a,respectively.The extreme minimum temperature rise had contributed the most part to the significant increase in temperature.The warm winters in Turpan,Hami,Dunhuang and Lenghu are obvious;the frequency of extreme high temperatures in the summer of Ruoqiang and Tieganlike is accelerated.The extreme precipitation in the Lop Nor region has concentrated in the 1970 s,1980s,and early 21 st Century;especially in the 21 st Century,the extreme precipitation cycle has been shortened to 2.3 years,and the frequency of extreme precipitation has increased.(5)The temperatures in the Lop Nor region showed a downward-upward trend,with the year of mutations concentrated in 1987(±2a)and 1996(±1a).Compared with temperature,the precipitation changes are more complicated and internal differences are significant.The annual precipitation is generally on the rise,but the difference in the year of the mutation is large: in Hami has mutations in 1986 and 1991;in Ruoqiang the mutation occurred in 1980 and 2004;in Tieganlike it changed in 1970 and 2013;in Dunhuang a mutation occurred in 1968.The precipitation in spring is generally on the rise.The year of the mutation is concentrated in the early 21 st Century.The variation of precipitation in summer is small.The years of mutation are concentrated in the early 1970 s and early 1980 s.The precipitation in autumn is generally decreasing-upward,and the year of mutation is concentrated in the early 21 st Century.The precipitation in winter generally showed a downward-upward trend,and the year of mutation was concentrated in the 1960 s and the early 21 st Century.