2005-2008年5、6月华南暖区暴雨与高、低空急流和南亚高压关系的统计分析  

STATISTICAL ANALYSIS OF THE RELATIONSHIP AMONG WARM SECTOR HEAVY RAINFALL,UPPER AND LOWER TROPOSPHERIC JET STREAM AND SOUTH ASIA HIGH IN MAY AND JUNE FROM 2005 TO 2008

作　　者：丁治英[1] 刘彩虹[1] 沈新勇[1] 

机构地区：[1]南京信息工程大学,气象灾害省部共建教育部重点实验室,江苏南京210044

出　　处：《热带气象学报》2011年第3期307-316,共10页Journal of Tropical Meteorology

基　　金：国家基础研究发展项目规划“973”2009CB421503);国家自然科学基金(40975037、40775033)共同资助

摘　　要：利用2005—2008年5月和6月的NCEP 1°×1°分析资料和气象台站常规气象资料,对我国华南地区的暖区暴雨进行了统计分析,并且以θse场与暖区暴雨的不同配置进行了分类,将华南暖区暴雨划分为三种类型,在分类的基础上进行了合成分析。统计及合成分析得出5月和6月的暖区暴雨有明显的差异:5月1型暖区暴雨出现最多,6月2型暖区暴雨出现最多,3型暖区暴雨仅发生于6月;5月暖区暴雨受高空急流的影响比较大,多发生于高空急流的右后方,离南亚高压脊线较远;6月形成暖区暴雨的高空急流较弱,暖区暴雨多发生在南亚高压脊线附近;5月形成暖区暴雨的南部系统相对稳定,而6月南部系统尺度变化较大。其相同点为:5、6月各类暖区暴雨多发生于850 hPa低空急流的后部(包括左后、右后),且均发生于850 hPa左右的南风辐合区中,因此低层南风辐合是产生暖区暴雨的重要机制之一,除6月1型暖区暴雨外,其他类暖区暴雨区的南侧中层均有干区配合。5、6月2型暖区暴雨相似度最大,1型暖区暴雨的相似度最小。The primary datasets used in this study comprise the U.S.National Centers for Environmental Prediction 1 °×1 ° reanalysis data and conventional surface data.A statistical analysis of warm-sector heavy rainfall in South China in May and June from 2005 to 2008 was performed.Based on the spatial distributions of the pseudo-equivalent potential temperature,warm-sector heavy rainfall was divided into three categories and the characteristics of each type of warm-sector heavy rainfall were investigated by means of composite analysis.It was found as follows.The first type of warm-sector heavy rainfall mainly occurs in May,the second type mainly appears in June,and the third type only occurs in June.Most of the warm-sector heavy rainfall occurs at the entry of the right rear portion of an upper-tropospheric jet axis and is far away from the South Asia High ridge line in May;it mainly occurs around the South Asia High ridge line in June,and the upper-tropospheric jet axis is farther north.A southern atmosphere circulation system which induces warm-sector heavy rainfall is relatively stable in May but may have large-scale changes in June.Warm-sector heavy rainfall mainly occurs in the convergence field back（including left rear and right rear） of the lower-tropospheric jet axis at 850 hPa,therefore forming a warm-sector heavy rainfall that is much more related to the convergence field of south wind in lower layers.There are always dry sectors at the middle levels at the south side of a warm rainstorm area expect the first type of warm-sector heavy rainfall in June.The second type of rainfall has much similarity while the first type has the minimum similarity in May and June.

关 键 词：天气学 统计特征 华南暖区暴雨分类 南亚高压 高空急流 低空急流 

分 类 号：P434.4[天文地球—大气科学及气象学]