摘要
利用Weather Research and Forecasting(WRF)中尺度数值模式,结合常规观测资料、地面加密自动气象站资料、云迹风等资料较好地模拟了2006年6月10日严重影响浙江的一次强飑线演变过程,得到了与实况比较接近的飑线中尺度特征,结果表明:强对流活动与边界层内的中尺度辐合有密切联系,除了雷暴出流在其前沿形成的阵风锋外,还模拟得到了宁波东部地区的中尺度气流辐合线(简称宁东辐合线);宁东辐合线呈现出明显的西干东湿、东侧上湿下干和弱的稳定层结特征,其存在阻挡了边界层顶强不稳定的东传;在宁东辐合线东侧的山谷地带,近地面形成一个尺度仅为10～20km的中尺度垂直闭合环流,该环流导致地面弱的东风气流又反过来加强了宁东辐合线。当之前已存在的雷暴出流形成的阵风锋辐合线与宁东局地辐合线相遇时,形成一条新的阵风锋,边界层之上的湿度显著增强,强不稳定得到逐步释放,加剧了对流的爆发,天气现象进一步加重。
A mesoscale numerical mode named Weather Research and Forecasting（WRF）was utilized to simulate a squall line occurring on 10 June 2006 which severely impacted Zhejiang Province by using conventional observational data,mesonet data,and cloud motion wind data.The results showed that the mesoscale convergence line/zone in the boundary layer was associated with organized strong convection.There was a simulated mesoscale convergence line in eastern Ningbo besides that a gust front formed by forward outflow and lay in front of the squall line.The local convergence line in eastern Ningbo,which prevented the eastward propagation of strong instability at the top of the boundary layer,could be characterized by a weak stable stratification and that it is drier in the west and wetter in the east.In addition,a mesoscale closed vertical circulation with about 10-20-km scale generated near the surfaceto the east of the local convergence line.In reverse,the vertical circulation prompted weak easterly flow to enhance the local convergence line.It produced a new gust front when the existing gust front and the local convergence line met,which could intensify humidity at the top of the boundary layer and release strong instability gradually.Especially in the front of the new gust front,it resulted in intensification of upward movement and breaking out of strong convection.
出处
《大气科学》
CSCD
北大核心
2010年第6期1127-1140,共14页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金资助项目40975021
中国气象科学研究院灾害天气国家重点实验室重点项目2008LASW-A03
关键词
数值模拟
同化
飑线
暴雨
阵风锋
中尺度辐合线
numerical simulation
assimilation
squall line
heavy rainfall
gust front
mesoscale convergence line
