甘肃河东地区近30年季节极端气温指数变化与环流影响

Seasonal Variation Characteristics of Extreme Temperature Index and Its Influence on Circulation in Hedong Area of Gansu Province in the Past 30 Years

基于1988-2017年61个气象站点逐日气温数据,分析了甘肃河东地区近30年各季节极端气温指数的时空变化特征,并分析了ENSO和AO对河东地区极端气温指数的影响。结果表明:近30年河东地区处于变暖态势中,各季节气温日较差(DTR)、暖夜日数(TN90p)、暖昼日数(TX90p)均呈增加趋势,冷夜日数(TN10p)、冷昼日数(TX10p)均呈减少趋势。甘南高原极端气温指数在各区中变化最显著,春季是各极端指数变化最显著的季节,也是河东地区DTR变化趋势不同于全国的影响因素。DTR于1992年突变后增加,平均气温于1996-1997年发生突变,其余极端气温指数于1997年突变,极端气温指数在其自身以及平均气温突变年份前后的变化反映了区域变暖的态势。El Ni?o影响河东地区冬季DTR的增加,La Ni?a影响冬季TX10p日数增加,AO正相位时河东地区夏季高温事件更易发生。

Based on the daily temperature data of 61 meteorological stations from 1988 to 2017,the spatial and temporal variation characteristics of the seasonal extreme temperature index in Hedong region of Gansu province in the past 30 years were analyzed,and the influence of ENSO and AO on the extreme temperature index in Hedong region was analyzed. The results showed that in the past 30 years,the daily temperature range(DTR),the number of warm night days(TN90p)and the number of warm day days(TX90p)in each season increased,while the number of cold night days(TN10p)and the number of cold day days(TX10p)decreased. The change of extreme temperature index in Gannan Plateau is the most significant among different regions,and Spring is the season with the most significant change of each extreme index,which is also an important factor that makes the variation trend of DTR in Hedong region different from that in the whole country. The DTR increased after the abrupt change in 1992,the average temperature changed in 1996-1997,and the rest of the extreme temperature index changed in 1997. The changes of the extreme temperature index before and after the abrupt change in itself and the mean temperature year reflected the trend of regional warming. El Ni?o affects the increase of DTR in winter,La Nina affects the increase of TX10p days in winter in Hedong region,and high temperature events are more likely to occur in summer in Hedong region when AO is in positive phase.