摘要
随着全球变暖加剧,复合湿热天气在世界各地呈现显著加剧趋势,中国东部也是极端湿热事件的高发区。为更好了解中国复合湿热事件的变化特征,基于1961—2020年中国日最高湿球温度观测数据,利用趋势分析、小波功率谱分析和广义极值分布分析等方法,对中国日最高湿球温度的时空变化特征进行了深入分析。结果表明:1)1961—2020年中国日最高湿球温度平均值和最大值主要呈“南高北低”的分布特点,最大值高值区集中在中国南部和四川盆地。全国日最高湿球温度平均值呈增强趋势,最大值无明显的变化趋势。全国平均值有2~6 a尺度的周期震荡,全国最大值在多个时间段和时间尺度有短周期。2)全国极端湿热阈值分布与日最高湿球温度最大值比较类似,极端湿热强度呈现增强趋势,全国极端湿热频次也以0.098 d/a的速率增多。西北东部地区极端湿热强度增强幅度最大,但南方地区呈减弱趋势;西北东部、南方和东北地区极端湿热频次持续增多。3)多年一遇事件的阈值分布同样与最大值分布类似,多年一遇事件频次呈现显著的区域特征,多年一遇事件主要发生在四川盆地,其中西北东部地区显著增多,南方地区有减少趋势。
In recent years,the occurrence of compound humid-heat weather has been increasing worldwide due to global warming.These events predominantly affect subtropical coastal areas,posing significant threats to the environment,economy,and various other aspects.Eastern China,in particular,is highly susceptible to such extreme,compound humid-heat events.Neglecting the influence of humidity on high-temperature weather could lead to a serious underestimation of the associated hazard level.Given China s vast territory,the distribution and variation of humid-heat events can vary across different regions.In eastern China,a substantial population is exposed to perilous humid-heat conditions.Therefore,it is crucial to study the changing characteristics of humid-heat events in China.This study aims to explore the spatial-temporal changing patterns of compound humid-heat events across China from 1961 to 2020 using daily maximum wet-bulb temperature(WBT).WBT was calculated from daily relative humidity,daily maximum temperature,and daily mean pressure.Results indicated that:(1)Both the mean and maximal daily maximum WBT in China exhibit a similar spatial pattern,with warmer temperatures in the south and cooler temperatures in the north.The regions of southern China and the Sichuan Basin emerge as hotspots for maximal daily WBT.While the mean daily maximum WBT shows an upward trend,the maximal daily maximum WBT does not exhibit a significant trend.The mean daily maximum WBT generally exhibits a 2—6 year period,whereas the maximal daily maximum WBT has relatively shorter periods.Meanwhile,changes in mean daily maximal WBT and maximal daily maximum WBT vary across different regions of China.Both the mean daily maximum WBT and the maximal daily maximum WBT show a decreasing trend in eastern Xinjiang,while they both increase rapidly in eastern Northwest China.The mean daily maximum WBT increases slightly in southern China and eastern Northwest China,while the maximal daily maximum WBT increases in northeastern China and decreases in southern China.(2)The distribution of extreme humid-heat thresholds in China is similar to that of the daily maximum WBT.The intensity of extreme humid-heat events shows an increasing trend,while the frequency of such events increases at a rate of 0.098 d/a.The intensity of extreme humid-heat events has increased the most in eastern Northwest China,but it has shown a decreasing trend in southern China.However,the frequency of extreme humid-heat events has increased in most areas of China over the past 60 years.(3)The threshold distribution of the extreme events with return periods of 10(20)years in China is also similar to that of the maximum daily maximum WBT.Such events mainly occur in the Sichuan Basin,with a significant increase in the northwest and eastern regions of China and a decreasing trend in southern China.The measurement of relative humidity was changed to automatic methods in the early 21st century,and relative humidity decreased abnormally during the same period,which may be related to a sudden drop in eastern Xinjiang.Therefore,the homogenizing process for relative humidity data is necessary in future research.The findings of this study have significant implications for climate change policies.Improving our understanding of changes in humid-heat events in China can help us better respond to these climate-related disasters.
作者
张书惠
华维
陈活泼
ZHANG Shuhui;HUA Wei;CHEN Huopo(School of Atmospheric Sciences/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province/Engineering Laboratory of Meteorological Disasters Prediction and Early Warning of Sichuan Province,Chengdu University of Information Technology,Chengdu 610225,China;Nansen-Zhu International Research Centre,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China)
出处
《大气科学学报》
CSCD
北大核心
2024年第2期300-312,共13页
Transactions of Atmospheric Sciences
基金
国家自然科学基金资助项目(42088101,42075021)。
关键词
湿球温度
长期趋势
气候变化
小波分析
wet-bulb temperature
long-term trend
climate change
wavelet analysis
