王一娇, 张新主, 夏思悦. 湖南省暖季极端高温和降水复合事件特征分析[J]. 内江师范学院学报, 2023, 38(4): 47-52. DOI: 10.13603/j.cnki.51-1621/z.2023.04.010
    引用本文: 王一娇, 张新主, 夏思悦. 湖南省暖季极端高温和降水复合事件特征分析[J]. 内江师范学院学报, 2023, 38(4): 47-52. DOI: 10.13603/j.cnki.51-1621/z.2023.04.010
    WANG Yijiao, ZHANG Xinzhu, XIA Siyue. Temporal and spatial characteristics and correlation analysis of composite events of extreme heat and precipitation in warm season in Hunan Province[J]. Journal of Neijiang Normal University, 2023, 38(4): 47-52. DOI: 10.13603/j.cnki.51-1621/z.2023.04.010
    Citation: WANG Yijiao, ZHANG Xinzhu, XIA Siyue. Temporal and spatial characteristics and correlation analysis of composite events of extreme heat and precipitation in warm season in Hunan Province[J]. Journal of Neijiang Normal University, 2023, 38(4): 47-52. DOI: 10.13603/j.cnki.51-1621/z.2023.04.010

    湖南省暖季极端高温和降水复合事件特征分析

    Temporal and spatial characteristics and correlation analysis of composite events of extreme heat and precipitation in warm season in Hunan Province

    • 摘要: 基于湖南省1979-2021年暖季(5-9月)逐日降水和最高气温站点数据,通过百分位阈值法提取极端高温、极端降水和无降水事件,探讨极端降水与无降水前三天内的高温复合情况,并归类为暖湿事件和暖干事件,结合EOF和copula函数分析两类复合事件时空特征及极端气候因子间的相依结构特征.结果表明:(1)空间上,湖南省各站点复合事件都有发生,暖干事件的频数是暖湿事件的20多倍.对于暖湿事件,11.35%的极端降水事件前三天内都会发生极端高温,平均每年经历0.74次,其主要分布在西北山地和南岭山地;对于暖干事件,25.81%的无降水发生前三天内都会发生极端高温,其主要分布在洞庭湖平原地区、湖南东部、雪峰山与武陵山之间山谷地区.时间上,两类复合事件都呈增长趋势且都集中在6、7月份,尤其在2010年以来,增速最快且多出现在人口密集的城市群.(2)两类复合事件的时空异常特征表明:暖湿事件第一模态的空间分布表现为全场一致型,第二模态的空间分布表明湘中与湘北平原、谷地地区呈反相变化形式;暖干事件发生频数的第一模态表明湖南大部分地区和湘南地区呈反相变化形式,第二模态则显示了湘东部分与湘西山地呈反相变化.(3)湖南省最高气温与降水量之间具有较为明显的相关关系,且t-copula函数的相依结构结果验证其具体相关性.从联合概率分布来看,二者整体表现出负相关性,而从二者的t-copula概率密度函数图来看,其在极值方面具有较为明显的正相依性.

       

      Abstract: Based on the daily precipitation and maximum temperature data of warm season (May to September) from 1979 to 2021 in Hunan Province, the extreme high temperature, extreme precipitation and no precipitation events are extracted by percentile threshold method. The high temperature composite situation in the first three days of extreme precipitation and no precipitation is discussed and classified into warm wet events and warm dry events. The temporal and spatial characteristics of the two composite events and the dependent structure characteristics between extreme climate factors are analyzed by combined use of EOF and copula function. The results show that: (1) spatially, composite events have occurred at all observation stations in Hunan Province, with the concurrence of warm dry events 20 times bigger than that of warm wet events. For warm and humid events, 11.35% of extreme precipitation events will experience extreme high temperature within the previous three days, with an average of 0.74 times per year, which were mainly distributed in the northwest mountains and Nanling Mountains. For warm dry events, 25.81% of the extreme high temperature events occurred within three days before no precipitation occurred, which were mainly distributed in the Dongting Lake Plain, eastern Hunan, and the valley area between Xuefeng mountain and Wuling Mountain. In terms of time, both types of composite events show an increasing trend and are concentrated in June and July. Especially since 2010s, the fastest growth rate mostly occurs in densely populated urban agglomerations. (2) The spatio-temporal anomaly characteristics of the two types of composite events show that the spatial distribution of the first mode of warm and humid events is consistent in the whole field, and the spatial distribution of the second mode shows that the central Hunan and Northern Hunan plain and valley areas are reversed. The first mode of the occurrence frequency of warm dry events shows that most parts of Hunan and southern Hunan have an inverse change, while the second mode shows that the eastern part of Hunan and the western mountain have an inverse change. (3) There is an obvious correlation between the maximum temperature and precipitation in Hunan Province, and the dependence structure results of t-copula function verify the specific correlation: from the joint probability distribution, the two on the whole show a negative correlation, while from the t-copula probability density function diagram of the two, they have an obvious positive correlation in the extreme values.

       

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