冬季热带中东太平洋海温变化对广西大雾日数的影响  

The impact of winter sea surface temperature change in the central eastern tropical Pacific on the number of heavy fog days in Guangxi

作　　者：覃皓 郑凤琴 孙崇智 QIN Hao;ZHENG Fengqin;SUN Chongzhi(Guangxi Zhuang Autonomous Region Meteorological Observatory,Nanning 530022,China;Guangxi Zhuang Autonomous Region Climate Center,Nanning 530022,China;Guangxi Zhuang Autonomous Region Meteorological Service Center,Nanning 530022,China)

机构地区：[1]广西壮族自治区气象台,广西南宁530022 [2]广西壮族自治区气候中心,广西南宁530022 [3]广西壮族自治区气象服务中心,广西南宁530022

出　　处：《气象与环境学报》2024年第1期79-87,共9页Journal of Meteorology and Environment

基　　金：广西重点研发计划项目(桂科AB20159013);中国气象局创新发展专项项目(CXFZ2022J029)共同资助。

摘　　要：利用1979—2020年广西80站逐日大雾资料、Hadley中心海表面温度资料以及NCEP/NCAR再分析资料,结合相关分析、合成分析以及信息流因果理论,分析了冬季热带中东太平洋海温变化对广西大雾日数的影响。结果表明:冬季热带中东太平洋海温是广西雾日数的显著影响源,海温偏高(偏低)一定程度上导致了广西冬季大雾天气多发(少发)。冬季热带中东太平洋海温偏暖,引起上空上升运动异常,减弱了沃克环流,导致热带西太平洋出现下沉异常。热带西太平洋下沉异常导致局地负的加热异常,从而在热带西太平洋北侧菲律宾一带对流层低层激发出反气旋异常。广西在菲律宾异常反气旋西北侧的西南风影响下,一方面动力上使得近地面层偏北冬季风风速减小,有利于大雾形成和维持;另一方面使得南海至西北太平洋一带维持显著的异常反气旋水汽环流,有利于南海水汽向华南输送,使得广西上空整层水汽通量辐合增强,对流层低层绝对湿度增大,水汽逐渐饱和,近地面层结稳定度增强,为大雾形成提供有利条件,最终导致雾日增多。冬季热带中东太平洋海温偏冷时则形势大致相反,广西大雾少发。Using daily heavy fog data from 80 stations in Guangxi from 1979 to 2020,sea surface temperature data from the Hadley Centre,and NCEP/NCAR reanalysis data,and employing correlation analysis,composite analysis,and information flow causality theory,this study analyzed the impact of winter sea surface temperature change in the central eastern tropical Pacific on the number of heavy fog days in Guangxi.The results show that the winter sea surface temperature in the central eastern tropical Pacific is a significant source of influence on the number of fog days in Guangxi,with higher(lower)temperatures contributing to more(fewer)heavy fog events in winter.Higher sea surface temperature in the central eastern tropical Pacific causes abnormal rising motions aloft,weakening the Walker Circulation and leading to abnormal descending motions over the tropical western Pacific,resulting in locally negative heating anomalies,and in turn triggering anomalous anticyclones in the lower troposphere around the Philippines to the north of the tropical western Pacific.Under the influence of the southwest winds on the northwest side of the anomalous anticyclone over the Philippines,Guangxi experiences a dynamic reduction in near-surface northerly winter monsoon wind speed,favoring the formation and maintenance of heavy fog.Furthermore,this situation makes a significant anomalous anticyclonic moisture circulation from the South China Sea to the northwest Pacific maintained,facilitating the transportation of moisture from the South China Sea to southern China,which enhances the entire atmospheric column′s moisture flux convergence over Guangxi,increases the absolute humidity in the lower troposphere,and generates gradually saturated the water vapor near the surface,and then enhances the stability of the near-surface layer,and provides favorable conditions for heavy fog formation,ultimately leads to an increase in foggy days.Conversely,lower winter sea surface temperatures in the central eastern tropical Pacific generally leads to the o

关 键 词：海温 反气旋异常 层结稳定度 

分 类 号：P461.2[天文地球—大气科学及气象学]