Changing structures of summertime heatwaves over China during 1961–2017  

作　　者：Ning AN Zhiyan ZUO 

机构地区：[1]State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China [2]Department of Atmospheric and Oceanic Sciences/Institute of Atmospheric Sciences,Fudan University,Shanghai 200438,China [3]Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science and Technology,Nanjing 210044,China

出　　处：《Science China Earth Sciences》2021年第8期1242-1253,共12页中国科学（地球科学英文版）

基　　金：supported by the National Key R&D Program(Grant No.2016YFA0601502);the National Natural Science Foundation of China(Grant Nos.41822503 and 41375092).

摘　　要：Despite the prevalence of artificial separation of daytime and nighttime hot extremes, they may actually co-occur or occur sequentially. Considering their potential lead-lag configuration, this study identified an entire heatwave period as consecutive days with either daytime or nighttime hot extremes and investigated the changes of the prevalence and sequence of daytime and nighttime hot extremes during heatwaves over China from 1961 to 2017. It was found that the majority(82%) of heatwaves were compound heatwaves that had both daytime and nighttime hot extremes exceeding the 90 th percentile-based thresholds, while only 7%(11%) were purely daytime(nighttime) heatwaves that contained only daytime(nighttime) hot extremes. During the entire periods of compound heatwaves, daytime hot extremes usually occurred one day or a few days before nighttime hot extremes, which was in accordance with the daily variations in radiation and meteorological conditions, such as the increasing surface humidity and cloud cover, and decreasing solar radiation during the entire heatwave periods. From 1961 to2017, compound heatwave numbers exhibited the sharpest increase with a statistically significant trend of 0.44 times decade-1, in contrast to an insignificant trend of 0.00 times decade-1 for purely daytime heatwaves and a significant trend of 0.09 times decade-1 for purely nighttime heatwaves. Within the compound heatwave periods, hot nights were starting earlier and ending later, and numbers of concurrent daytime-nighttime hot extremes increased significantly at 0.20 days decade-1. In particular,urban area were not only subject to increasingly more frequent and longer compound heatwaves, but also to more occurrences of concurrent daytime-nighttime hot extremes with more serious impact. This study provides instructions for researchers to customize and select appropriate heatwave indices.

关 键 词：Heatwaves Daytime-nighttime coupling URBANIZATION Meteorological conditions 

分 类 号：P423[天文地球—大气科学及气象学]