Characteristics Of Atmosphere Temperature Change And Monitoring Analysis Of Typical Extreme Weather In Xinjiang

This paper focused on the trends of air temperature in the troposphere and the lower stratosphere(500hPa-50hPa)and surface air temperature over the Tarim basin from 1980 to 2018,and the reasons for the reversal trends of air temperature over the basin were reasonably explained from the angle of ozone variation.For the study of extreme weather in Xinjiang,selecting two snowstorms in Urumqi as typical examples,using satellite inversion products from AIRS and HYSPLIT backward trajectory tracking algorithm,the sources and transport paths of cold mass,warm mass and water vapor in the two processes were monitored and analyzed,and the key factors affecting the intensity and duration of snowstorms were discussed in terms of water vapor allocation.Based on the studies above,the following conclusions could be drawn:(1)Since 1997,the air temperature in the troposphere and the lower stratosphere(500hPa-50hPa)over the Tarim basin had a reversal trend.From 1980 to 1997,the lower stratosphere showed an obvious cooling trend and the troposphere showed a warming trend.From 1998 to 2018,the cooling trend of the lower stratosphere had changed into a warming trend,and the warming trend of the troposphere had weakened significantly,and there were even cooling trends in autumn and winter.(2)The total ozone over the Tarim basin also showed a reversal trend around 1997,and the reversal trend was most significant in winter.The reversal trend of total ozone over the basin indicated that stratospheric ozone is in recovery.(3)By analyzing the correlation between air temperature at different levels and total ozone over the Tarim basin,it was found that there existed a positive correlation between stratospheric temperature and total ozone,and a negative correlation between tropospheric temperature and total ozone.It can be inferred that the recovery of stratospheric ozone was an important reason for the reversal trend of air temperature over the Tarim basin since 1997.(4)By analyzing the monitoring results of two extreme snowstorms,it could be found that the water vapor affecting snowstorms in northern Xinjiang mainly came from the Black Sea,Caspian Sea,Aral Sea,Lake Balkash and the Arabian Sea;cold mass mainly came from Nordic region and Siberia;the sources and transport paths of warm mass were generally consistent with water vapor.(5)During the process of extreme snowstorm in Urumqi on Dec 10-12,2015,continuous transport of water vapor from the Arabian Sea is the key reason for the unprecedented intensity of the snowstorm.By comparing the two snowstorms,it could be found that sufficient and sustained water vapor replenishment was an important factor to determine the intensity and duration of snowstorms.