Extreme Climatic Events in Southern Xinjiang in Recent 50 Years

The study is based on the statistics of daily precipitation,maximum temperature and minimum temperature gathered by 22 meteorological stations over Southern Xinjiang from1961 to 2008,and computed 20 extreme climatic indices,using the method of linear fitting to analyze temporal variability and spatial characteristics.The results are as follows:extreme precipitation and temperature indices significantly increase in Southern Xinjiang.Simple daily rainfall intensity index,annual total wet day precipitation,monthly maximum 1-day precipitation,monthly maximum 5-day precipitation and very wet days significantly increase by 0.79,59.9,4.52,7.56 and 23.32 mm/10 a, respectively;consecutive dry days shows a downward trend at rate of-2.39 d/10a; the extreme precipitation indices of the north of Southern Xinjiang(the strip in the Southern Tianshan mountains) increase dramatically,the next are the south and east,Tarim basin increases a little,the partial meteorological stations of the western show a weak downward trend;monthly minimum value of daily maximum temp,monthly minimum value of daily minimum temp, monthly maximum value of daily maximum temp,monthly maximum value of daily minimum temp,warm nights,warm days, summer days and diurnal temperature range show a rising trend;While the frost days,ice days,cold nights,cold days and cold spell duration days indicate a trend of decline,among them,the diurnal temperature range and cold nights reduce fluctuantly; cold days increases first and then decreases,while the warm nights and warm days are reversed,the cold spell duration days decreases first and then increases to peak, then declines.