山西省夏季极端高温的时空变化及特征分析

Spatio-temporal variation and characteristic analysis of extreme high temperature in summer during 1971-2020 in Shanxi Province

利用山西省67个国家气象观测站1971-2020年夏季6~8月的日最高气温数据,依据百分位法计算、统计得到山西省夏季极端高温阈值、强度和天数,并通过反距离加权法、克里金法、薄盘光滑样条法插值得到山西省夏季极端高温阈值、强度的空间变化规律,评价了极端高温综合强度;在此基础上通过Theil⁃Sen法分析了山西省夏季最高气温的变化规律,并通过Mann⁃Kendall法对最高气温进行突变检验。结果表明:1971-2020年山西省夏季极端高温阈值变化范围为29.4~37.7 ℃,强度为30.2~38.4 ℃,自北向南递增;1971年以来山西省夏季极端高温天数为5.8~8.0 d·a^(-1),晋南>晋北>晋中,晋西>晋东,1997年前及2011年前后极端高温综合强度较弱,而1997-2011年及2011-2020年极端高温综合指数变化幅度加大,极端性整体增强;山西省夏季最高气温整体呈显著上升,平均上升速率为0.3℃·10 a^(-1),晋北、晋中和晋南上升速率分别为0.3 ℃·10 a^(-1)、0.3 ℃·10 a^(-1)和0.2 ℃·10 a^(-1);突变检验结果表明晋北和晋中区域最高气温突变发生时间为20世纪90年代末,晋南区域突变发生在2000年左右。研究结果对未来山西省、华北地区及全国极端高温的预测、极端高温影响评估及对策提出具有重要意义。

The temporal and spatial variation characteristics of threshold value,strength and frequency of extreme high temperature in summer(June to August)of Shanxi Province were calculated and counted by percentile method,and interpolated by the methods of Inverse Distance Weight,Kriging and Anuspline based on the data of daily the maximum temperature from 67 national meteorological observational stations in Shanxi Province from 1971 to 2020.On this base,the comprehensive strength of extreme high temperature was evaluated.The study further analyzed the long­term trend of the maximum temperature with the method of Theil­Sen,and the mutation test of the maximum temperature was conducted by Mann­Kendall test.The study results showed that the threshold values and strength of extreme high temperature were 29.4~37.7 ℃ and 30.2~38.4 ℃ respectively with an increase trend from north to south in summer of Shanxi Province from 1971 to 2020.In the past 50 years,frequency of extreme high temperature in summer was 5.8~8.0 d·a^(-1),which was higher in the southern Shanxi than that in the middle and north of Shanxi and that in the western Shanxi was higher than that in the eastern Shanxi.The comprehensive intensity of extreme high temperature before 1997 and around 2011 was weak,but the amplitude and extremity overall increased from 1997 to 2011 and from 2011 to 2020.The maximum temperature in most areas of Shanxi Prov­ince showed a significant increase trend,with an average rate of 0.3 ℃·10 a^(-1) in summer during 1971-2020.The increase rate of the maximum temperature in the northern,middle and southern Shanxi were 0.3 ℃·10 a^(-1),0.3 ℃·10 a^(-1) and 0.2 ℃·10 a^(-1),respectively.The maximum temperature change abruptly in late 1990 s in the north and center of Shanxi,and the mutation occurred around the year of 2000 in southern Shanxi Province.The study results are of great significance to the prediction of extreme high temperature,impact assessment and the proposal of countermeasure in Shanxi Province,North China and the whole country in the future.