大气科学学报
大氣科學學報
대기과학학보
JOURNAL OF NANJING INSTITUTE OF METEOROLOGY
2012年
1期
51-63
,共13页
中尺度对流系统%边界层辐合线%边界层冷池%干线
中呎度對流繫統%邊界層輻閤線%邊界層冷池%榦線
중척도대류계통%변계층복합선%변계층랭지%간선
mesoscale convective system%boundary layer convergence line%cold pool in the boundary layer%dryline
采用具有较高时空分辨率的地面观测资料以及WRF（Weather reasearch and forecasting）模式输出资料，分析了2009年6月29一-30日梅雨锋暴雨过程中两类不同的中尺度对流系统（rnesoscale convective system，MCS）边界层特征及边界层对两类MCS的触发维持机理，重点分析了海平面气压场特征、边界层冷池、干线及其在MCS中的影响。结果表明：两类中尺度对流系统的海平面气压特征存在着明显的差异，对流爆发阶段地面风场存在辐合线，再次激发阶段气压场呈“跷跷板”型的中尺度扰动，即由前置中低压和后置中高压组成，最强的对流带位于中低压和中高压之间的过渡区内；边界层辐合线是第一类中尺度对流系统（MCSl）维持的重要因素；MCSl爆发后边界层冷池生成，冷池前的冷出流与低层环境风产生的强辐合触发了第二类中尺度对流系统（MCS2）；存在于中低压和中高压之间的中尺度干线是MCS2的重要特点之一。
採用具有較高時空分辨率的地麵觀測資料以及WRF（Weather reasearch and forecasting）模式輸齣資料，分析瞭2009年6月29一-30日梅雨鋒暴雨過程中兩類不同的中呎度對流繫統（rnesoscale convective system，MCS）邊界層特徵及邊界層對兩類MCS的觸髮維持機理，重點分析瞭海平麵氣壓場特徵、邊界層冷池、榦線及其在MCS中的影響。結果錶明：兩類中呎度對流繫統的海平麵氣壓特徵存在著明顯的差異，對流爆髮階段地麵風場存在輻閤線，再次激髮階段氣壓場呈“蹺蹺闆”型的中呎度擾動，即由前置中低壓和後置中高壓組成，最彊的對流帶位于中低壓和中高壓之間的過渡區內；邊界層輻閤線是第一類中呎度對流繫統（MCSl）維持的重要因素；MCSl爆髮後邊界層冷池生成，冷池前的冷齣流與低層環境風產生的彊輻閤觸髮瞭第二類中呎度對流繫統（MCS2）；存在于中低壓和中高壓之間的中呎度榦線是MCS2的重要特點之一。
채용구유교고시공분변솔적지면관측자료이급WRF（Weather reasearch and forecasting）모식수출자료，분석료2009년6월29일-30일매우봉폭우과정중량류불동적중척도대류계통（rnesoscale convective system，MCS）변계층특정급변계층대량류MCS적촉발유지궤리，중점분석료해평면기압장특정、변계층랭지、간선급기재MCS중적영향。결과표명：량류중척도대류계통적해평면기압특정존재착명현적차이，대류폭발계단지면풍장존재복합선，재차격발계단기압장정“교교판”형적중척도우동，즉유전치중저압화후치중고압조성，최강적대류대위우중저압화중고압지간적과도구내；변계층복합선시제일류중척도대류계통（MCSl）유지적중요인소；MCSl폭발후변계층랭지생성，랭지전적랭출류여저층배경풍산생적강복합촉발료제이류중척도대류계통（MCS2）；존재우중저압화중고압지간적중척도간선시MCS2적중요특점지일。
By using the surface observational data at high spatial and temporal resolutions together with simulations of the Weather Research and Forecasting model, the characteristics of atmospheric boundary layer and mechanisms of two different types of MCSs（ mesoscale convective systems） which led to the Meiyu front rainstorm that occurred over the Yangtze River basin during 29-30 June 2009 are analyzed, focusing on sea level pressure field, boundary layer cold pool, dryline and its effect in MCS. The results show that there are obvious differences for the sea level pressure fields corresponding to the two distinct MCSs （referred as MCS1 and MCS2 ）. MCS1 corresponds to boundary layer convergence line while MCS2 is composed of a mesolow and a mesohigh which are located in front of and behind the severe convective zone, respectively. The severe convective zone occurred in the transition zone between the mesolow and mesohigh. The boundary layer convergence line is an important factor in maintainingMCS1. The convergence between the boundary outflow before the boundary layer cold pool caused by the developing process of MCS1 and lower-layer wind triggered MCS2. The mesoscale dryline in the transition zone was an important characteristic of MCS2.
