近30a河东地区极端气温时空变化

利用61个气象站1988—2017年逐日最高气温、最低气温和平均气温资料,采用线性倾向估计、Mann-Kendal检验、滑动t以及相关分析方法,对河东地区极端气温事件的时空变化特征进行研究,结果表明:①河东地区近30 a日最高气温的极大(小)值、日最低气温的极大(小)值、年平均最高(低)气温、夏日日数、热夜日数、暖昼(夜)日数、气温日较差、暖日持续日数、生物生长季呈现增大(加)趋势,霜冻日数、冰冻日数、冷昼(夜)日数、冷日持续日数呈现减小(少)趋势;②暖指数的变暖幅度大于冷指数,昼指数的变暖幅度大于夜指数,陇东高原地区变暖幅度最大,甘南高原地区变暖幅度最小;③多数指数的突变点在20世纪90年代中后期和21世纪初期;④多数极端气温指数与经度和海拔高度显著相关,河东地区极端气温指数的变化与区域性增暖有密切联系。

Spatiotemporal Change of Extreme Temperature in the Hedong Region in Recent 30 Years

Themethods of linear regression, Mann-Kendal test, sliding T-test and correlationanalysis were used to analyze the spatiotemporal variation of extremetemperature events in the Hedong region based on the daily temperature(maximum, minimum and average) data from 61 meteorological stations in thestudy area during the period of 1988-2017. The resultsshowed that: ①In recent 30 years, thedaily maximum and minimum temperature values, annual mean maximum and minimumtemperature values, summer duration, tropical nights, warm days, warm nights, dailytemperature range, warm-day duration and growing season were in an increasetrend. Whereas the frost days, ice days, cold days, cold nights and cold-dayduration were in a decrease trend; ② The change ranges of warming indices were obviously higher thanthose of cold ones. The warming ranges of diurnal indices were higher thanthose of nocturnal ones. The warming range was the highest in the Loess Plateauin east Gansu Province but the lowest in the Gannan Plateau; ③ Abrupt change of the most temperature indices occurred in the mid-1990sand early 21st century; ④ Most extreme temperatureindices were closely related to the longitude and altitude. The variation ofextreme temperature indices in the Hedong region was closely related to the regionalwarming.