华南前汛期雨涝强、弱年的确定及其环流特征对比  

Determination of strong and weak rain-waterlogging years in pre-rainy season over South China and their circulation features comparison

作　　者：罗艳艳[1,2] 何金海[1] 邹燕[3] 孙蔡亮 

机构地区：[1]南京信息工程大学大气科学学院,南京210044 [2]莆田市气象局,福建莆田351100 [3]福建省气候中心,福州350001

出　　处：《气象科学》2015年第2期160-166,共7页Journal of the Meteorological Sciences

基　　金：福建省自然科学基金资助项目(2014J01146);福建省气象局青年科技专项(2013q16)

摘　　要：用区域性暴雨过程综合强度评估方法,在对1961—2010年华南前汛期逐场暴雨过程评估的基础上,通过定义华南区域雨涝强度指数(RWI),划分和确定了雨涝强、弱年,并对雨涝强、弱年的环流特征进行合成分析。结果显示:(1)RWI存在显著的年际变化和年代际变化特征。雨涝强度在1990s初以后呈现明显的增加趋势,雨涝强年明显增多。(2)雨涝强(弱)年,南亚高压偏南(北),副高位置偏西(东),欧亚中高纬500 h Pa位势高度差值场自西向东呈现+-+的波列分布,则有利(不利)于华南区域降水的发展和持续;(3)华南前汛期雨涝的强(弱)与大气低层来自华中—华南北部的偏北风输送加强(减弱)、高原东南侧的偏西风和经西太平洋—南海进入华南的西南风及水汽输送异常加强(减弱)有着密切的关系。而与来自孟加拉湾进入华南的偏南风及水汽输送强(弱)呈现反相关。(4)雨涝强(弱)年,冷空气活动频率较高(低),持续时间较长(短),强中心偏南(北)。且暖湿空气较早(晚)到达25°N地区,并在30°N以南地区维持时间较长(短),季风推进快(慢)。Based on the assessments on the heavy rainfall processes occurred in pre-rainy season o- ver South China from 1961 to 2010 by the regional rainfall intensity model, the strong（weak） rain-water- logging years were divided and labeled through defining the rain-water logging index （RWI）, and their circulation features were also compositely analyzed.Results show that： （1） RWI implies prominent inter- annual and inter-deeadal variation characteristics. In the early 1990s, the rain-waterlogging intensity ten- ded obviously to increase trend and the strong rain-waterlogging years also increased. （2） In strong （weak） rain-waterlogging years, the South Asia high extends southward （northward）, subtropical high extends farther westward（eastward） and the composite differences at 500 hPa height in mid-high latitude in Eurasia shows ＇ ＋ - ＋＇ （ - ＋ -） waveforms from west to east, which is all advantageous （ disadvanta- geous） to the development and continuity of rainfall in South China. （3） The strong （weak） rain-water-logging is intimately linked with the strengthening（weakening） northerly winds from Central China-north- ern South China in the low layer of atmosphere and the anomalous strengthening（weakening） of westerly wind from the southeastern plateau, southwesterly winds from western Pacific- South China Sea to South China, as well as water vapor transportation. （4）In strong（weak） rain-waterlogging years , cold air ac- tivity is active （inactive） and has longer （shorter） duration with more south （north） location of strong center, moreover warm air arrives at 25°N area earlier（ later）, its duration at further south of 30°N is longer（shorter） and the monsoon moves forward faster （slower）.

关 键 词：暴雨 华南前汛期 雨涝强度 强度指数 环流特征 合成分析 

分 类 号：P458.121[天文地球—大气科学及气象学]