doi:  10.3878/j.issn.1006-9895.1812.18231
2016年“7.19”京津冀极端降水系统的动热力结构及不稳定条件分析

Evolution of Dynamic and Thermal Structure and Instability Condition Analysis of the Extreme Precipitation System in Beijing-Tianjin-Hebei on July 19 2016
摘要点击 570  全文点击 326  投稿时间:2018-09-14  
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基金:  国家自然科学基金项目41475054、41661144024、41530427,河北省科技计划项目17275409D,国家重点基础研究发展计划项目2015CB453201
中文关键词:  暴雨  动热力系统  位势不稳定  位势散度
英文关键词:  Torrential rain  Dynamic and thermal structure  Potential instability  Potential divergence
           
作者中文名作者英文名单位
张景ZHANG Jing南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心,南京210044;中国科学院大气物理研究所云降水物理与强风暴院重点实验室(LACS),北京100029
周玉淑ZHOU Yushu中国科学院大气物理研究所云降水物理与强风暴院重点实验室(LACS),北京100029;中国科学院大学,北京100049
沈新勇SHEN Xinyong南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心,南京210044;中国科学院大气物理研究所云降水物理与强风暴院重点实验室(LACS),北京100029
李小凡and LI Xiaofan浙江大学地球科学学院,杭州310027
引用:张景,周玉淑,沈新勇,李小凡.2019.2016年“7.19”京津冀极端降水系统的动热力结构及不稳定条件分析[J].大气科学,43(4):930-942,doi:10.3878/j.issn.1006-9895.1812.18231.
Citation:ZHANG Jing,ZHOU Yushu,SHEN Xinyong,and LI Xiaofan.2019.Evolution of Dynamic and Thermal Structure and Instability Condition Analysis of the Extreme Precipitation System in Beijing-Tianjin-Hebei on July 19 2016[J].Chinese Journal of Atmospheric Sciences (in Chinese),43(4):930-942,doi:10.3878/j.issn.1006-9895.1812.18231.
中文摘要:
      利用NCEP/NCAR 的GFS再分析资料,结合中国气象局气象信息中心提供的全国自动站观测降水量资料、CMORPH卫星反演降水资料、FY2反演降水资料和雷达定量估测降水产品融合的降水资料,对造成2016年7月19~21日北京—天津—河北(以下简称京津冀)地区的极端降水天气系统动热力结构演变以及不稳定条件进行了诊断分析,揭示了京津冀地区上空不同气压层上天气尺度系统的配置,水汽条件,降水发生的垂直运动条件及不稳定层结演变情况。结果表明:(1)500 hPa呈现东高西低的环流形势,与700 hPa低涡和高低空急流相配合,副高北抬阻挡华北地区低涡的东移,导致低涡在京津冀地区停滞是此次降水发生的环流背景;(2)低层的低涡东移发展与中高层正涡度叠加对暴雨发生有重要作用;(3)引用位势散度分析对流不稳定度变化的原因表明,降水区后部的京津冀西南地区,低层的位势不稳定主要由位势散度的水平风垂直切变部分决定,代表水平风垂直切变和大气湿斜压的共同作用,弱降水区以及降水区后方的低层位势散度为负值,有利于该区域位势不稳定加强,强降水区及降水区前方位势散度为正值,抑制了位势不稳定发展。位势散度变化可以通过影响大气稳定度变化进而影响降水落区,位势散度的高值区对应了降水大值区,尤其是700 hPa位势散度对降水落区有很好的指示作用,可以结合位势散度的变化对降水落区进行预估。
Abstract:
      The evolution of dynamic and thermal structure and instability condition of an extreme precipitation system in Beijing-Tianjin-Hebei are analyzed using the NCEP/NCAR Global Forecast System (GFS) data combined with national automatic stations observations of precipitation provided by the Meteorological Information Center of China Meteorological Administration, the CMORPH satellite precipitation data and the fusion of precipitation data from the FY2 precipitation and radar quantitative estimation of precipitation. This study reveals the configuration of weather systems in different air pressure zones over the Beijing-Tianjin-Hebei region. Vertical motion, water vapor condition and unstable stratification evolution during the precipitation process are explored. The results are as follows. (1) The circulation at 500 hPa presented an east-high-west-low pattern, which was coordinated with a low-level vortex at 700 hPa and jet streams in low and high levels. The subtropical high blocked the eastward movement of the low-level vortex in North China, making it stagnant in the Beijing-Tianjin-Hebei region. (2) The development and eastward-moving of the low level vortex was important for the occurrence of the rainstorm. (3) The potential divergence analysis was applied to explore changes in convective instability. Results indicate that in the rear of the precipitation area, lower-level potential instability was mainly determined by vertical wind shear, which reflected the joint effects of vertical wind shear and moist baroclinicity. Lower-level potential divergence was negative in weak precipitation area and behind the precipitation area, which was conducive to regional potential instability. Potential divergence was positive in strong precipitation area and in front of precipitation area, inhibiting the development of potential instability. The change in potential divergence affected precipitation region through affecting the atmospheric stability. The high value region of potential divergence corresponded to high value region of precipitation, especially the 700 hPa potential divergence was a good indicator for precipitation region, which could be estimated by the change of potential divergence at 700 hPa.
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