典型厄尔尼诺期间台风降水δ18O变化分析:以2018年22号台风“山竹”为例  

Analysis on the variation of typhoon precipitation δ18O during typical El Nino event: A case study of Typhoon Mangkhut(2018)

作　　者：杨云月 许涛 罗翠榆 刘娟[3] 姜修洋[1,2] YANG Yunyue;XU Tao;LUO Cuiyu;LIU Juan;JIANG Xiuyang(School of Geographical Sciences,Fujian Normal University,Fuzhou 350007,China;Institute of Geography,Fujian Normal University,Fuzhou 350007,China;Institute of Environmental Research at Greater Bay,Guangzhou University,Guangzhou 511400,China)

机构地区：[1]福建师范大学地理科学学院,福建福州350007 [2]福建师范大学地理研究所,福建福州350007 [3]广州大学大湾区环境研究院,广东广州511400

出　　处：《热带海洋学报》2020年第4期34-41,共8页Journal of Tropical Oceanography

基　　金：国家自然科学基金项目(41672170);福建省自然科学基金项目(2017J01654)。

摘　　要：台风因其特殊的物理结构,带来的降雨有别于一般的暴雨事件,其降水稳定同位素组成与一般的大气降水事件也有较大的差异。本文根据2018年第22号台风"山竹"登陆前后广州、东莞两地气象资料和每小时间隔的降水样品收集,分析了此次台风在两地的降水稳定同位素变化特征及其影响因素。台风"山竹"影响期间,广州降水δ18O值变化范围为–5.7‰~–19.2‰,变化幅度达13.5‰,其平均值为–15.5‰;东莞降水δ18O值变化范围为–7.3‰~–20.0‰,变化幅度达12.7‰,平均值为–14.8‰;两地降水δ18O值均呈现为3个阶段倒U型的变化特征。受到蒸发作用的影响,两地台风前端和尾端的降水氧同位素值相对偏正,其中广州为–5.7‰~–9.3‰,东莞为–7.3‰~–8.1‰。两地台风中端的降水稳定同位素值极端偏负,δ18O值变化范围分别为–16.0‰~–19.2‰(广州)和–13.0‰~–20.0‰(东莞),是该地区迄今为止已报道的最为偏负的降水δ18O值。分析认为,在厄尔尼诺状态下生成的远源台风"山竹"强度增强,其内部具有更强的对流和水汽循环过程,导致降水δ18O值极端偏负。The rainfall caused by typhoon is different from the other precipitation event due to its unique physical structure. The stable isotope composition of typhoon precipitation is also quite different from that of a general precipitation event. Based on meteorological data before and after the landing of Typhoon Mangkhut(2018) in Guangzhou and Dongguan and stable isotope data of precipitation at hourly resolution, we analyzed the characteristics of the stable isotope variation of the typhoon precipitation and its influencing factors. During the influence of Typhoon Mangkhut, the δ18 O value of precipitation in Guangzhou ranged from –5.7‰~–19.2‰, with a variation of 13.5‰;and the average value was –15.5‰. The variation of δ18 O value in Dongguan was –7.3‰~–20.0‰, with a variation of 12.7‰;and the average was –14.8‰. The variations of δ18 O value of precipitation in the two places both showed the three-stage variation characteristics of inverted U-shape. Due to the influence of evaporation, the precipitation oxygen isotope values in the typhoon at the front and back were relatively positive in two places, of which Guangzhou was(–5.7‰~–9.3‰, and Dongguan was –7.3‰~–8.1‰. The stable isotope values of precipitation in the typhoon central area of the two places were extremely negative, ranging from –16.0‰ to –19.2‰(Guangzhou) and from –13.0‰ to –20.0‰(Dongguan), which were the most negative precipitation δ18 O values reported in this region so far. According to the analysis, the generated distant typhoon intensity was enhanced during the El Nino. Thus, the stronger convection and water-vapor circulation in Typhoon Mangkhut(2018) led to extreme negative δ18 O value of its precipitation.

关 键 词：台风“山竹” 降水δ18O 微物理过程 厄尔尼诺 

分 类 号：P732.3[天文地球—海洋科学]