Synoptic pattern and severe weather associated with the wide convection over Southeast China during the summer monsoon period
Synoptic pattern and severe weather associated with the wide convection over Southeast China during the summer monsoon period
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DOI：
10.1007/s13351-014-4069-4
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发表时间：
2015-02
影响因子：
3.2
通讯作者：
Hui Wang;Yali Luo;Renhe Zhang
中科院分区：
文献类型：
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作者：
Hui Wang;Yali Luo;Renhe Zhang
根据热带降雨测量使命（TRMM）降水雷达观测，宽对流（WC）被定义为连续对流回波超过40 dBZ，伴随着近地面降雨面积超过1000 km 2。1998-2010年夏季风期间，我国东南部地区WC出现频率最高的区域为华东中部平原的平原区。当该地区发生WC时，用客观分类方法将500 hPa大气场分为三种类型，即：深槽控制型（DTr）、副热带高压维持型（STH）和台风影响型（TYPH）分别占WC出现次数的20.8%、52.8%和26.4%。DTr型出现时间最早（5月16-31日），6月下半月出现次数最多; STH型在7月上半月出现一个显著的出现高峰; Typh型多出现在7 ~ 8月。在这三种天气型中，DTr型是该地区空气最干、最冷的天气型，短历时强降水发生次数最少。在DTr型下最常出现强风，这可能是由于对流层中低层之间空气湿度差异最大。在所有的天气形势下，地面冰雹都是罕见的，这可能与所有天气形势下的潮湿环境空气和STH形势下的高冻结层（> 5 km）有关。
Based on the Tropical Rainfall Measuring Mission (TRMM) precipitation radar observations, wide convection (WC) is defined as contiguous convective echoes over 40 dBZ, accompanied with a near surface rainfall area exceeding 1000 km2. In Southeast China, the maximal occurrence frequency of WC takes place over the flat land region in the central plain of East China during the summer monsoon period of 1998–2010. When WC occurs in this region, the 500-hPa atmospheric fields are categorized into three patterns by using an objective classification method, i.e., the deep-trough-control (DTr) pattern, the subtropical-high-maintenance (STH) pattern, and the typhoon-effect (Typh) pattern, which respectively accounts for 20.8%, 52.8%, and 26.4% of the total WC occurrences. The DTr pattern starts to emerge the earliest (16–31 May) and occurs the most often in the second half of June; the STH pattern has a significant occurrence peak in the first half of July; the Typh pattern occurs mostly in July and August.Nearly all WC occurrences in this region are associated with thunderstorms, due to large convective available potential energy and abundant moisture. Among the three synoptic patterns, the DTr pattern features the driest and coldest air in the region, leading to the least occurrences of short-duration heavy rainfall. Strong winds occur the most often under the DTr pattern, probably owing to the largest difference in air humidity between the mid and low troposphere. Hail at the surface is rare for all occurrences of WC, which is probably related to the humid environmental air under all weather patterns and the high (> 5 km) freezing level under the STH pattern.