利用常规气象观测资料、区域自动站资料、卫星云图和雷达产品及NCEP再分析资料,对2016年7月9日新乡暖区特大暴雨过程成因进行了综合分析。结果表明:该过程强降水持续时间长、强度大、分布不均匀、致灾严重,属暖区极端强降水,500 h Pa低...利用常规气象观测资料、区域自动站资料、卫星云图和雷达产品及NCEP再分析资料,对2016年7月9日新乡暖区特大暴雨过程成因进行了综合分析。结果表明:该过程强降水持续时间长、强度大、分布不均匀、致灾严重,属暖区极端强降水,500 h Pa低涡和700 h Pa切变线是其主要影响系统;台风外围东南暖湿气流在太行山迎风坡(新乡西部)辐合抬升使特大暴雨区上空长时间维持深厚湿层,500 h Pa低涡南压所携带的弱冷平流与低层暖平流在新乡上空叠加进一步增加了大气层结不稳定,为暴雨发生提供了水汽和位势不稳定条件;200 h Pa显著分流区"抽吸作用"、太行山地形抬升和中低层低涡和切变线使新乡上空出现深厚垂直上升运动是暴雨形成的动力机制;华北中南部大范围高湿环境、深厚暖云层和湿层以及异常偏低的自由对流高度和抬升凝结高度与中等偏强的对流有效位能,是导致新乡高降水效率的有利条件;新乡强降水中心由2个孤立的β中尺度对流系统(MβCS)合并造成,其系统内部若干低质心对流单体则由太行山东侧山前长时间维持的中尺度辐合系统产生;雷达反射率因子反映出低质心暖云降水回波特征,强回波列车效应明显,新乡特大暴雨由积云(对流)为主的积层混合降水回波长时间滞留造成。展开更多
An extremely heavy rainfall event occurred in Zhengzhou,China,on 20 July 2021 and produced an hourly rainfall rate of 201.9 mm,which broke the station record for China's Mainland.Based on radar observations and a ...An extremely heavy rainfall event occurred in Zhengzhou,China,on 20 July 2021 and produced an hourly rainfall rate of 201.9 mm,which broke the station record for China's Mainland.Based on radar observations and a convection-permitting simulation using the WRF-ARW model,this paper investigates the multiscale processes,especially those at the mesoscale,that support the extreme observed hourly rainfall.Results show that the extreme rainfall occurred in an environment characteristic of warm-sector heavy rainfall,with abundant warm moist air transported from the ocean by an abnormally northward-displaced western Pacific subtropical high and Typhoon In-Fa(2021).However,rather than through back building and echo training of convective cells often found in warm-sector heavy rainfall events,this extreme hourly rainfall event was caused by a single,quasi-stationary storm in Zhengzhou.Scale separation analysis reveals that the extreme-rainproducing storm was supported and maintained by the dynamic lifting of low-level converging flows from the north,south,and east of the storm.The low-level northerly flow originated from a mesoscale barrier jet on the eastern slope of the Taihang Mountain due to terrain blocking of large-scale easterly flows,which reached an overall balance with the southerly winds in association with a low-level meso-β-scale vortex located to the west of Zhengzhou.The large-scale easterly inflows that fed the deep convection via transport of thermodynamically unstable air into the storm prevented the eastward propagation of the weak,shallow cold pool.As a result,the convective storm was nearly stationary over Zhengzhou,resulting in record-breaking hourly precipitation.展开更多
文摘利用常规气象观测资料、区域自动站资料、卫星云图和雷达产品及NCEP再分析资料,对2016年7月9日新乡暖区特大暴雨过程成因进行了综合分析。结果表明:该过程强降水持续时间长、强度大、分布不均匀、致灾严重,属暖区极端强降水,500 h Pa低涡和700 h Pa切变线是其主要影响系统;台风外围东南暖湿气流在太行山迎风坡(新乡西部)辐合抬升使特大暴雨区上空长时间维持深厚湿层,500 h Pa低涡南压所携带的弱冷平流与低层暖平流在新乡上空叠加进一步增加了大气层结不稳定,为暴雨发生提供了水汽和位势不稳定条件;200 h Pa显著分流区"抽吸作用"、太行山地形抬升和中低层低涡和切变线使新乡上空出现深厚垂直上升运动是暴雨形成的动力机制;华北中南部大范围高湿环境、深厚暖云层和湿层以及异常偏低的自由对流高度和抬升凝结高度与中等偏强的对流有效位能,是导致新乡高降水效率的有利条件;新乡强降水中心由2个孤立的β中尺度对流系统(MβCS)合并造成,其系统内部若干低质心对流单体则由太行山东侧山前长时间维持的中尺度辐合系统产生;雷达反射率因子反映出低质心暖云降水回波特征,强回波列车效应明显,新乡特大暴雨由积云(对流)为主的积层混合降水回波长时间滞留造成。
基金supported by the National Science Foundation of China(Grant No.42122036)the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0105)+2 种基金the National Key R&D Programs of China(2018YFC1507300)the National Science Foundation of China(Grant No.91837207)the Beijing Climate Center(QHMS2021008).
文摘An extremely heavy rainfall event occurred in Zhengzhou,China,on 20 July 2021 and produced an hourly rainfall rate of 201.9 mm,which broke the station record for China's Mainland.Based on radar observations and a convection-permitting simulation using the WRF-ARW model,this paper investigates the multiscale processes,especially those at the mesoscale,that support the extreme observed hourly rainfall.Results show that the extreme rainfall occurred in an environment characteristic of warm-sector heavy rainfall,with abundant warm moist air transported from the ocean by an abnormally northward-displaced western Pacific subtropical high and Typhoon In-Fa(2021).However,rather than through back building and echo training of convective cells often found in warm-sector heavy rainfall events,this extreme hourly rainfall event was caused by a single,quasi-stationary storm in Zhengzhou.Scale separation analysis reveals that the extreme-rainproducing storm was supported and maintained by the dynamic lifting of low-level converging flows from the north,south,and east of the storm.The low-level northerly flow originated from a mesoscale barrier jet on the eastern slope of the Taihang Mountain due to terrain blocking of large-scale easterly flows,which reached an overall balance with the southerly winds in association with a low-level meso-β-scale vortex located to the west of Zhengzhou.The large-scale easterly inflows that fed the deep convection via transport of thermodynamically unstable air into the storm prevented the eastward propagation of the weak,shallow cold pool.As a result,the convective storm was nearly stationary over Zhengzhou,resulting in record-breaking hourly precipitation.
