CAJ | 학술논문

2010年6月中国南方发生持续性强降水，其强度与2008年6月相当，超过近年来其他年份。但是，与2008年6月相比，2010年6月对流层中低层低值系统活动在青藏高原至长江中下游地区异常频繁，副热带高压（副高）位置异常偏西、强度偏强，导致低层异常风场辐合区及强降水区域相对偏北。分析2010年6月14-24日中国南方连续出现的4次持续性强降水过程，发现南亚高压、对流层中层的中纬度槽脊和西太平洋副高以及低层切变线和东移低涡是造成持续性强降水的主要天气系统。利用 WRF模式对2010年6月强降水过程实施显式对流集合模拟试验，在控制试验重现观测到的地面降水和天气系统特征的基础上，在敏感性试验中将青藏高原的地表短波反照率修改为1．0，对比两组模拟试验的结果表明：控制试验中青藏高原的地表感热加热作用使得高原及其周边地区的大气温度发生变化，相应的热成风平衡调整使得对流层低层至高层大气环流和天气系统特征发生显著变化，增强了中国南方的持续性降水。200 hPa 青藏高原西部形成反气旋性环流异常，东部形成气旋性环流异常，青藏高原东部南下的冷空气加强，中国南方辐散增强；500 hPa 青藏高原北部的脊加强，中国东部的槽加深，副高西北侧的西南风明显增强，从青藏高原向下游传播的正涡度也显著加强；850 hPa 的低涡强烈发展并逐步东移，华南沿海的西南低空急流更为强盛，导致降水区的水汽辐合、上升运动及降水强度都增强。
2010년6월중국남방발생지속성강강수，기강도여2008년6월상당，초과근년래기타년빈。단시，여2008년6월상비，2010년6월대류층중저층저치계통활동재청장고원지장강중하유지구이상빈번，부열대고압（부고）위치이상편서、강도편강，도치저층이상풍장복합구급강강수구역상대편북。분석2010년6월14-24일중국남방련속출현적4차지속성강강수과정，발현남아고압、대류층중층적중위도조척화서태평양부고이급저층절변선화동이저와시조성지속성강강수적주요천기계통。이용 WRF모식대2010년6월강강수과정실시현식대류집합모의시험，재공제시험중현관측도적지면강수화천기계통특정적기출상，재민감성시험중장청장고원적지표단파반조솔수개위1．0，대비량조모의시험적결과표명：공제시험중청장고원적지표감열가열작용사득고원급기주변지구적대기온도발생변화，상응적열성풍평형조정사득대류층저층지고층대기배류화천기계통특정발생현저변화，증강료중국남방적지속성강수。200 hPa 청장고원서부형성반기선성배류이상，동부형성기선성배류이상，청장고원동부남하적랭공기가강，중국남방복산증강；500 hPa 청장고원북부적척가강，중국동부적조가심，부고서북측적서남풍명현증강，종청장고원향하유전파적정와도야현저가강；850 hPa 적저와강렬발전병축보동이，화남연해적서남저공급류경위강성，도치강수구적수기복합、상승운동급강수강도도증강。
Persistent severe rainfall occurs over southern China during June 2010,with a magnitude being comparable to June 2008 and exceeding the other recent years.The June of 2010 is characterized by frequent occurrences of low-value systems in the middle- and low- troposphere from the Qinghai-Tibet Plateau to the lower reaches of the Yangtze River,and the significant-ly intensified West Pacific subtropical high (WPSH),leading to more northward located low-level anomalous wind convergence and rain bands compared to June of 2008.Analyzing the four successive persistent severe rainfall events over southern China during 14-24 June 2010,it is found that the South Asian high,the middle-latitude trough and ridge and the WPSH in the mid-dle troposphere,as well as the shear lines and eastward-moving vortices in the lower troposphere are the main synoptic systems inducing the persistent severe rainfall.Moreover,an ensemble of convection-permitting simulations (CTL)is carried out using the WRF model for these rainfall events in June 2010.The ensemble mean successfully reproduces the observed evolutions of precipitation and weather systems.Another ensemble of simulations (SEN)with the surface albedo over the Tibetan Plateau and its southern slope being changed artificially to one,otherwise it is identical to CTL,is carried out.Comparison between CTL and SEN suggests that the surface sensible heating of the Tibetan Plateau in CTL significantly effects the temperature dis-tributions over the plateau and its surroundings and the thermal wind adj ustment consequently changes atmospheric circulations and properties of synoptic systems from the lower to upper troposphere,which significantly intensifies the persistent severe precipitation over southern China.Specifically,at 200 hPa,anticyclonic and cyclonic anomalies are formed over the western and eastern plateau,respectively,which enhances the southward cold air intrusion along the eastern plateau and intensifies the di-vergence over southern China;at 500 hPa,the ridge over the northern plateau and the trough over eastern China are strength-ened,the southwesterly flows along the northwestern side of the subtropical high are intensified,and the positive vorticity propagation from the plateau to the downstream is also enhanced significantly;and at 850 hPa,the low-pressure vortices strongly develop and move eastward while the southwesterly low-level j et over the South China coasts is intensified as shown in CTL,leading to stronger water vapor convergence and upward motion over the precipitation region.