| (1)From the time change of Xinjiang region 56 a,the cold index of the extreme temperature index is a downward trend,and the warm index is an upward trend;the extreme index all show a slight upward trend;The overall trend is declining;(2)From the perspective of spatial variation,the relative index in the extreme temperature index is basically the same in the six climate regions in the north and south.In other extreme temperature indices,the northern Xinjiang cold index is larger than the southern Xinjiang region,and the warm index is in the northern Xinjiang.The mountain climate zone is larger than the southern Xinjiang mountain climate zone,but the southern Xinjiang basin climate zone is larger than the northern Xinjiang basin climate zone;the extreme cold index of the north and south Xinjiang is decreasing,the Tianshan north-south climate zone and the Tacheng zone are the most significant,and the extreme warming index is increasing.There is such a trend in both the north and the south,but the trend is not significant;(3)From the time change of Xinjiang region 56 a,except for the single-day maximum precipitation and the number of persistent droughts,the other indicators showed a downward trend,while the extreme precipitation changes were weak,and the change trend was obvious.There are only three indicators of R95 extreme precipitation,total precipitation on rainy days,and number of days of persistent drought.(4)From the perspective of spatial trends,the spatial difference of the extreme precipitation index is obvious.The extreme precipitation index has obvious differences in the climate zones of the northern and southern Xinjiang.The meteorological sites with higher rising tendency rate are mainly concentrated in the north and south climate regions of Tianshan and Yili,and the sites with lower decline tendency rate are mainly in the Ili River valley.(5)Comparative analysis of the extreme temperature event index,the extreme cold and warm index has different performances in different degrees of change,and the variation of the nightingale index also has different performances.Because the winter temperature increase is significantly greater than the summer,most of the cold index changes more than warm.The magnitude of the change in the index.(6)From the principal component analysis,the extreme temperature index is divided into three categories,the cumulative contribution rate of the first principal component reaches 79.8%,which accounts for 54.2% of the variance contribution rate,and theeigenvalues are also greater than 1.2;Correlation between extreme temperature indicesis analyzed in this paper.In general,only the correlation of the extremely low daily maximum temperature is weak,and the other indexes have a good correlation.(7)From the overall trend of Xinjiang,the extreme gas warming index is not related to the AO index,and the extreme temperature cold index and the AO index show a certain correlation.From the perspective of the north-south Xinjiang,the results of correlation analysis show that there is no correlation between the extreme temperature index and the AO index in southern Xinjiang;the northern Xinjiang region is more affected by the AO index.There was a significant positive correlation between TNn and TXn and AO index in the extreme temperature cold index.The correlation coefficients were 0.370*,0.397*,and there was a significant negative correlation between TN10 and TX10 and AO index.The correlation coefficients were-0.314*,-0.307*;the correlation between the extreme gas warming index and the AO index is not significant.(8)At the altitude point of view,the average value of the extreme precipitation indices decreases with increasing altitude;ENSO also has a certain impact on extreme precipitation.In the years of cold events,extreme precipitation is more,and ENSO events have a hysteresis effect on extreme precipitation.The extreme precipitation indices are well correlated and positively correlated(except for the number of days of persistent drought). |
PDF Full Text Request