摘要
利用国家气候中心提供的1958—2013年756个台站的逐日降水资料,定义了“弱台风大暴雨”事件,并对其发生的时间和空间分布特征进行统计分析,初步揭示了有利于“弱台风大暴雨”发生的大气异常环流特征。结果表明:“弱台风大暴雨”降水事件主要发生于5—10月,但初秋的10月该事件发生的占比最高;“弱台风大暴雨”降水事件发生次数在20世纪80年代中期后有明显的增加,整体呈现3~5a的周期振荡,盛夏(7—8月)是“弱台风大暴雨”降水事件的最多发生时段;空间上,初夏(5—6月)事件分布面积最小,盛夏最广;有利于“弱台风大暴雨”降水事件多发的大气环流场主要是在北极涛动正位相异常环流背景下,中纬度西风带较为稳定平直,有利于中纬度大气类环球遥相关型定常波列的持续稳定,使得东亚地区维持的高压异常环流有利于北方冷空气南下,与热带气旋带来的暖湿气流交汇;同时,西太平洋副热带高压的偏弱有利于登陆我国的台风停留时间增加以及水汽的源源不断输送,水汽的主要来源是北太平洋西南侧和南海、孟加拉湾等热带季风区。
This paper uses the daily precipitation data of 756 observation stations from 1958 to 2013 provided by National Climate Center of China Meteorological Administration to define “weak typhoon heavy rainfall event”(WTHRE).The spatial-temporal distribution of the frequency of WTHRE is statistically analyzed and anomalous atmospheric circulation favorable for WTHRE is investigated as well.The results are listed as follows.1) WTHRE occurs mostly from May to October, but its proportion in all precipitation events is the highest in October.2) The number of WTHRE increases significantly after the mid-1980s, presenting a periodic oscillation of three to 5 years.The midsummer (from July to August) is the main period of WTHRE.3) Spatially, the coverage area of WTHRE is the smallest in early summer (from May to June) and the biggest in midsummer.4) The favorable atmospheric circulation for WTHRE is under the anomalous circulation background of the positive phase of Arctic Oscillation, therefore, the mid-latitude westerly is relatively stable and straight, which is in favor of a continuous stable stationary wave train of circum-global teleconnection pattern in the middle latitude causing the anomalous high in East Asia.The maintenance of anomalous high in East Asia, which is favorable for the southward of cold air, meets the warm and humid air brought by tropical cyclones to form precipitation.5) At the same time, the weakening of the western Pacific subtropical high is beneficial to increase typhoon s duration of stay in China and sustain water vapor transport.The water vapor mainly comes from the tropical monsoon region such as the southwest side of the North Pacific, the South China Sea, and the Bay of Bengal.
作者
张希帆
黄菲
许士斌
王国复
ZHANG Xifan;HUANG Fei;XU Shibin;WANG Guofu(Key Laboratory of Physical Oceanography (Ocean University of China) of Ministry of Education, Qingdao 266100, China;Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266100, China;Ningbo Collaborative Innovation Center of Nonlinear Hazard System of Ocean and Atmosphere, Ningbo University, Ningbo 315000, China;National Climate Center, China Meteorological Administration, Beijing 100081, China)
出处
《海洋气象学报》
2019年第3期11-18,共8页
Journal of Marine Meteorology
基金
国家重大科学研究计划项目(2015CB953904)
国家自然科学基金项目(41575067)
关键词
时空分布
弱台风
大暴雨
台风降水
spatial-temporal distribution
weak typhoon
heavy rainfall
typhoon precipitation
