东北冷涡背景下的强对流天气具有局地性强、预报难度大的特点,冷空气的入侵往往对强对流天气的触发具有指示性意义。本文利用加密自动气象站地面观测数据、欧洲中期天气预报中心(European Center for Medium-Range Weather Forecasts,EC...东北冷涡背景下的强对流天气具有局地性强、预报难度大的特点,冷空气的入侵往往对强对流天气的触发具有指示性意义。本文利用加密自动气象站地面观测数据、欧洲中期天气预报中心(European Center for Medium-Range Weather Forecasts,ECMWF)的ERA5(ECMWF Reanalysis v5)再分析资料及风廓线雷达资料,分析2016年6月30日和2020年8月3日2次冷涡强降水天气的形势及动力、热力特点,重点对比分析了2次过程的干侵入特征。这2次强降水过程地面均为蒙古气旋配合,从地面至高空动力条件较好。降水发生前,上午天空晴好,对流层中高层有冷空气渗透,近地层湿度大,形成上干冷、下暖湿的不稳定层结。强降水发生前,中层干区自西向东侵入,高层高位涡区向下伸展,增强对流不稳定发展,中层位涡接近1×10^(-6)m^(2)·K·s^(-1)·kg^(-1)可以作为进入强降水时段的指标。干侵入指数呈偶极分布特征,可反映干冷空气和暖湿空气的相互作用,暴雨常发生在干侵入指数的密集带。当中高层干侵入指数正值区向中低层发展时,触发不稳定能量的释放,干侵入指数对强降水的落区及暴雨的增幅有较好的指示意义。展开更多
利用常规观测资料、NCEP/FNL再分析资料、多普勒雷达资料等,对2023年8月16日厦门市的雷暴天气进行分析,结果表明:此次雷暴天气发生在冷涡后部西北气流中,高低空温度差动平流加强了不稳定层结,高CAPE值和0~6 km弱垂直风切下,在阵风锋与...利用常规观测资料、NCEP/FNL再分析资料、多普勒雷达资料等,对2023年8月16日厦门市的雷暴天气进行分析,结果表明:此次雷暴天气发生在冷涡后部西北气流中,高低空温度差动平流加强了不稳定层结,高CAPE值和0~6 km弱垂直风切下,在阵风锋与海风锋碰撞区域形成脉冲风暴,具有爆发性强对流的典型特征。触发的新生对流沿着海风锋自东北向西南发展加强给闽南地区带来较大范围、较长时间的强降水天气;通过此次雷暴个例分析可知,沿海地区的预报员加强地面辐合线推移和演变的监测,一定程度上可以提前判断出多条辐合线碰撞触发新生对流,由此对此类强对流天气提前作出预报决断。Using conventional observation data, NCEP/FNL reanalysis data, Doppler radar data, etc., an analysis was conducted on the thunderstorm weather in Xiamen on August 16, 2023. The results showed that the thunderstorm occurred in the northwest airflow behind the cold vortex, and the high and low altitude temperature differential advection strengthened the unstable stratification. Under high CAPE values and weak vertical wind shear of 0~6 km, a pulse storm was formed in the collision area between the gust front and the sea breeze front, with typical characteristics of explosive strong convection. The newly triggered convection develops and strengthens along the sea breeze front from northeast to southwest, bringing large-scale and long-term heavy precipitation weather to the southern Fujian region. Through the analysis of this thunderstorm case, it can be seen that forecasters in coastal areas can strengthen monitoring of the movement and evolution of ground convergence lines, which can, to some extent, predict in advance the collision of multiple convergence lines triggering new convection, and thus make forecast decisions for such severe convective weather in advance.展开更多
文摘东北冷涡背景下的强对流天气具有局地性强、预报难度大的特点,冷空气的入侵往往对强对流天气的触发具有指示性意义。本文利用加密自动气象站地面观测数据、欧洲中期天气预报中心(European Center for Medium-Range Weather Forecasts,ECMWF)的ERA5(ECMWF Reanalysis v5)再分析资料及风廓线雷达资料,分析2016年6月30日和2020年8月3日2次冷涡强降水天气的形势及动力、热力特点,重点对比分析了2次过程的干侵入特征。这2次强降水过程地面均为蒙古气旋配合,从地面至高空动力条件较好。降水发生前,上午天空晴好,对流层中高层有冷空气渗透,近地层湿度大,形成上干冷、下暖湿的不稳定层结。强降水发生前,中层干区自西向东侵入,高层高位涡区向下伸展,增强对流不稳定发展,中层位涡接近1×10^(-6)m^(2)·K·s^(-1)·kg^(-1)可以作为进入强降水时段的指标。干侵入指数呈偶极分布特征,可反映干冷空气和暖湿空气的相互作用,暴雨常发生在干侵入指数的密集带。当中高层干侵入指数正值区向中低层发展时,触发不稳定能量的释放,干侵入指数对强降水的落区及暴雨的增幅有较好的指示意义。
文摘利用常规观测资料、NCEP/FNL再分析资料、多普勒雷达资料等,对2023年8月16日厦门市的雷暴天气进行分析,结果表明:此次雷暴天气发生在冷涡后部西北气流中,高低空温度差动平流加强了不稳定层结,高CAPE值和0~6 km弱垂直风切下,在阵风锋与海风锋碰撞区域形成脉冲风暴,具有爆发性强对流的典型特征。触发的新生对流沿着海风锋自东北向西南发展加强给闽南地区带来较大范围、较长时间的强降水天气;通过此次雷暴个例分析可知,沿海地区的预报员加强地面辐合线推移和演变的监测,一定程度上可以提前判断出多条辐合线碰撞触发新生对流,由此对此类强对流天气提前作出预报决断。Using conventional observation data, NCEP/FNL reanalysis data, Doppler radar data, etc., an analysis was conducted on the thunderstorm weather in Xiamen on August 16, 2023. The results showed that the thunderstorm occurred in the northwest airflow behind the cold vortex, and the high and low altitude temperature differential advection strengthened the unstable stratification. Under high CAPE values and weak vertical wind shear of 0~6 km, a pulse storm was formed in the collision area between the gust front and the sea breeze front, with typical characteristics of explosive strong convection. The newly triggered convection develops and strengthens along the sea breeze front from northeast to southwest, bringing large-scale and long-term heavy precipitation weather to the southern Fujian region. Through the analysis of this thunderstorm case, it can be seen that forecasters in coastal areas can strengthen monitoring of the movement and evolution of ground convergence lines, which can, to some extent, predict in advance the collision of multiple convergence lines triggering new convection, and thus make forecast decisions for such severe convective weather in advance.