基于MF-DFA的西安昼夜复合高温事件变化特征及影响因素  

Variation characteristics and its influencing factors of the compound hot extremes at daytime and nighttime in Xi’an City based on MF-DFA

作　　者：李双双[1,2] 王婷[1,2] LI Shuangshuang;WANG Ting(School of Geography and Tourism,Shaanxi Normal University,Xi’an 710119,Shaanxi,China;National Demonstration Center for Experimental Geography Education,Shaanxi Normal University,Xi’an 710119,Shaanxi,China)

机构地区：[1]陕西师范大学,陕西西安710119 [2]陕西师范大学地理国家级实验教学示范中心,陕西西安710119

出　　处：《干旱区地理》2022年第1期103-112,共10页Arid Land Geography

基　　金：国家自然科学基金(41877519,41701592)资助。

摘　　要：采用随机重排去趋势波动分析(MF-DFA)和极点对称模态分解法(ESMD),对1955—2019年西安市昼夜复合高温事件变化特征进行分析。结果表明:(1)气象站点迁移,造成对西安市极端高温变化趋势低估。其中,最高温原始数据与订正序列阈值相同;订正后,最低温阈值相对偏低0.2~0.5℃。(2)MF-DFA、90.0%和95.0%阈值方案识别高温事件年代变化具有相似性,而99.0%阈值和相对阈值方案是结论不确定性的主要来源。(3)在变化特征上,西安市昼夜复合高温事件兼顾3.3~3.8 a年际波动和趋势变化,20世纪80年代中期,昼夜复合高温天数呈现显著增多。(4)赤道西太平洋海温异常,可作为西安市昼夜复合高温预警的关键海区。即赤道西太平洋海温异常偏高时,往往对应西安市昼夜复合高温多发期,并指出南亚高压偏北、西太平洋副热带高压西伸,是影响西安市持续昼夜复合高温的环流机制。Improving research methods and regional adaptation measures depend on the refining of extreme weather processes.However,it is still a great challenge to refine the types of historical warming to more sophisticated extreme events.We identified three summertime hot extremes based on daily temperature(Tmax and Tmin)data obtained from 22 meteorological stations in Xi’an City,Shaanxi Province,China and the surrounding areas:independent hot days,independent hot nights,and compound hot extremes.The stochastic resort detrended fluctuation analysis(MF-DFA)and extreme-point symmetric mode decomposition(ESMD)were used to determine the variation of the compound hot extremes during the day and night in Xi’an City from 1955 to 2019.Meanwhile,the influencing factors of the annual fluctuation of the compound hot extremes during the day and night were analyzed.The results show that:(1)the highest temperature and threshold of the original data are the same as the homogenized data in Xi’an City.The threshold of the lowest temperature is relatively lower by 0.2-0.5℃after homogenization.As a result,the Xi’an station was relocated between urban areas and suburbs between 1959 and 2005,which resulted in an underestimation of the extreme temperature trend.(2)While the MF-DFA,90.0%,and 95.0%threshold schemes perform similarly well in identifying high temperature events,the 99.0%threshold and relative threshold schemes are the primary sources of uncertainty.(3)The interannual fluctuation and trend changes from 3.3-3.8 a were the compound hot extremes from 1955 to 2019.The number of compound hot extremes increased significantly in the mid-1980s,while the normal number of days and independent hot days decreased,and the number of independent hot nights and compound hot extremes increased.(4)The sea surface temperature(SST)anomaly in the equatorial western Pacific Ocean can be used as a key sea area for early warning of Xi’an City’s day and night combined high temperatures.The circulation analysis of the day-night composite high

关 键 词：气候变化 昼夜复合高温事件 厄尔尼诺 西安市 

分 类 号：P423[天文地球—大气科学及气象学]