doi:  10.3878/j.issn.1006-9895.1907.18187
浙江梅雨锋强降水的锋生及环流特征分析

Analysis on Frontogenesis and Circulation Characteristics of Mei-yu Front with the Zhejiang Heavy Precipitation
摘要点击 169  全文点击 44  投稿时间:2018-07-04  修订日期:2019-03-14
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基金:  浙江省预报员专项资助项目(41575042)资助
中文关键词:  梅雨锋  锋生函数  非地转风  (非)平衡风  次级环流
英文关键词:  Meiyu front  function of frontogenesis  ageostrophic wind  (un)balanced wind  secondary circulation
              
作者中文名作者英文名单位
徐亚钦XU Yaqin浙江省金华市气象局
吴松涛WU Songtao浙江浦江气象局
杨旺文YANG Wangwen浙江省浦江气象局
刘学华LIU Xuehua
黄艳Huang Yan
引用:徐亚钦,吴松涛,杨旺文,刘学华,黄艳.2020.浙江梅雨锋强降水的锋生及环流特征分析[J].大气科学
Citation:XU Yaqin,WU Songtao,YANG Wangwen,LIU Xuehua,Huang Yan.2020.Analysis on Frontogenesis and Circulation Characteristics of Mei-yu Front with the Zhejiang Heavy Precipitation[J].Chinese Journal of Atmospheric Sciences (in Chinese)
中文摘要:
      为了研究浙中西梅雨锋强降水的锋生及环流特征,以2016年06月15日一次典型梅雨为代表,采用ERA-INTERIM(0.25×0.25°)再分析资料、FY-2E云顶亮温和雷达资料,运用风场分解、合成分析等方法对锋生与强降水的对应关系及环流结构进行分析。结果表明:此次典型梅雨处于有利的天气尺度背景下,强降水区与中低层锋生区有较好对应。锋区维持时,强降水区伴随中层倾斜锋生和形变锋生;锋区南压时,强降水区伴随中层倾斜锋生和低层水平锋生。低层梅雨锋北侧为超地转偏西气流,南侧为非地转东南气流,它们分别影响了北侧非平衡偏北气流和南侧平衡西南气流的发展,从而影响锋生系统。在锋区存在低层地转偏差辐合、高层辐散的上升运动,形成次级环流上升支,锋后反之。此外,锋前低空纬向风为次地转,而锋后低空纬向风为超地转,高空纬向风为次地转,这进一步促进了次级环流的发展。合成场中,在200hPa西风槽槽后及槽前分别存在西北气流和西南气流显著增强区;在700hPa浙北地区存在东北气流显著增强区。合成锋生各分解项的水平及垂直空间分布与典型个例较类似。低层锋生主要由散度项贡献,形变项次之,倾斜项则起负作用;中层锋生主要由倾斜项贡献,形变项次之;高层锋消主要由倾斜项贡献。
Abstract:
      This paper analyses the frontogenesis and circulation characteristics in the central and western of Zhejiang represented by a typical Meiyu process on 15 June 2016.Based on the ERA-INTERIM (0.25×0.25°)reanalysis data, FY-2E TBB data, and radar data by means of wind decomposing and composite analysis to analyze the corresponding relationship between the frontogenesis and heavy precipitation, and circulation characteristics. The results indicated that this typical Meiyu was under a favorable synoptic-scale background, the heavy precipitation area had a close relationship to the middle-low-level frontogenesis. When the frontal zone maintained, it was accompanied by the middle-level deformation and tilting frontogenesis, when the frontal zone southward shift, it was accompanied by the middle-level tilting frontogenesis and low-level horizontal frontogenesis. The north side of the low-level Meiyu front had super-geostrophic westerly airflow, and the south side had strong southeast ageostrophic airflow, which affected the unbalanced northerly airflow on the north side and the balanced southwesterly airflow on the south side, thus affecting the development of frontogenesis. In frontal area, the upward motion, which formed the ascending branch of secondary circulation, was caused by low-level geostrophic deviation convergence and upper-level divergence. The post-frontal area was contrary. Additionally, in pre-front, the low-level zonal wind was sub-geostrophic, in post-front, the low-level zonal wind was super-geostrophic, and the upper-level zonal wind was sub-geostrophic. Thus further enhance the secondary circulation. After composite, there had significant enhancement area of the northwest and southwest airflow behind and in front of trough at 200hPa. In addition, there was a significant northeast wind variation area in northern Zhejiang at 700hPa.The horizontal and vertical distribution of decomposition items was similar between the composite and typical case. The low-level frontogenesis was mainly contributed by divergence term, followed by deformation term, and tilting term had a negative contribution. The middle-level frontogenesis was mainly contributed by tilting term, followed by deformation term. The upper-level frontolysis was mainly contributed by tilting term.
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