| 南海季风爆发前罕见连续3场暴雨特征及成因 |
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| 引用本文： | 吴乃庚,林良勋,曾沁,伍志方,金荣花,邓文剑.南海季风爆发前罕见连续3场暴雨特征及成因[J].应用气象学报,2013,24(2):129-139. |
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| 作者姓名： | 吴乃庚 林良勋 曾沁 伍志方 金荣花 邓文剑 |
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| 作者单位： | 1.广州中心气象台, 广州 510080 |
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| 基金项目： | 国家自然科学基金项目（41275053），公益性行业（气象）科研专项（GYHY201106003） |
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| 摘 要： | 2010年5月上中旬南海季风尚未爆发，广东一周内出现罕见的连续3场区域性暴雨 (下称连场暴雨)。利用常规气象观测资料和NCEP分析资料，从降水时间特征和环流形势对比了连场暴雨和持续性暴雨的异同，并应用局地经向环流数值模式诊断探讨其可能形成机制。结果表明:中高纬度地区阻塞形势建立对广东5月连场暴雨和6月持续性暴雨发生均尤为关键，连场暴雨期间阻塞高压位于乌拉尔山附近，降水与中纬度短波槽南下密切相关；而持续性暴雨期间阻塞高压偏东位于亚洲大陆中部，降水主要受热带西南季风北推影响。尽管大尺度环流背景相似，但3场暴雨过程天气系统配置差异较大。数值诊断结果进一步表明:激发连续3场暴雨的主要物理因子为潜热加热、温度平流和西风动量输送。潜热加热是此次连场暴雨的正贡献和正反馈的最直接因子，而西风动量输送和温度平流对暴雨发生有一定触发作用和指示意义 (超前0~1.5 d)。因此，分析和预报季风爆发前的连场暴雨过程，应注意中高纬度地区西风动量输送、冷暖平流活动和相应的天气形势演变。
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| 关 键 词： | 连场暴雨 持续性暴雨 阻塞高压 高空槽 冷空气 |
| 收稿时间： | 2012-04-22 |
Causal Analysis of Consecutive Torrential Rains in Guangdong Province Before the Onset of South China Sea Monsoon |
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| Wu Naigeng,Lin Liangxun,Zeng Qin,Wu Zhifang,Jin Ronghua and Deng Wenjian.Causal Analysis of Consecutive Torrential Rains in Guangdong Province Before the Onset of South China Sea Monsoon[J].Quarterly Journal of Applied Meteorology,2013,24(2):129-139. |
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| Authors: | Wu Naigeng Lin Liangxun Zeng Qin Wu Zhifang Jin Ronghua and Deng Wenjian |
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| Affiliation: | 1.Guangzhou Central Meteorological Observatory, Guangzhou 5100802.Department of Atmospheric Sciences, Sun Yat-sen University, Guangzhou 5102753.National Meteorological Center, Beijing 100081 |
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| Abstract: | Guangdong suffers from consecutive torrential rains before the onset of South China Sea Monsoon (SCSM) in May 2010, which is rarely seen in South China. Based on meteorological observations, regional automatic weather station data and NCEP data, the characteristics of the consecutive torrential rains are analyzed through a comparative analysis of consecutive torrentials and persistent rains. And the possible mechanism of the consecutive torrential rains are analyed with a complete (including dynamic and thermodynamic mechanisms) linear-diagnostic model for the local-meridional circulation.The results show that the blocking high plays an important role in both consectutive torrential rains and persistent rains. The consectcutive torrential rains are associated with the south-eastward propagation of short wave troughs and the blocking high located over Mount Ural, while the persistent torrential rains are associated with the northward movement of the SCSM and the blocking located over central of Asian continent. There are obvious differences among the weather patterns of the three consecutive torrential rains, although the large-scale background circulations are similar. "5.7" torrential rain occurs behind upper-level trough, lower-level shear line and cold front far from the rain belt, which is rarely observed in South China. "5.9" torrential rain is relatively typical since it occurs near the front and in the south of lower-level shear line, but upper-level short-wave trough is not clearly indentified. "5.14" torrential rain featured typical rainfall pattern in South China, heavy rainfall occurs in front of upper-level trough, in the south of low-level shear line and near the front.Numerical quantitative diagnosis shows that the contributors to the local meridional circulation associated with the consecutive torrential rains are mainly latent heating, horizontal temperature advection and westerly momentum transport. Latent heating is the major contributor and provides positive feedback to the torrential rain, while horizontal temperature advection and westerly momentum transport play an important role in triggering consecutive torrential rains (0—1.5 d prior to the torrential rains). The upper-level westly jet is in favor of the rising motion and upper-level divergence of Guangdong through the horizonal westerly momentum transport and vertical air mass adjustment. On the other side, the vertical westerly momentum transport and the upper-level trough provide favorable conditions for the southward moverment of cold air mass, which triggering stronger rising motion over Guangdong and more moisture convergence (latent heat release). Therefore, it is necessary to pay more attention to the evolution of mid-latitude synoptic circulation associated with westerly momentum and horizontal temperature advection in forecasting the consecutive torrential rains before the onset of SCSM. |
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| Keywords: | consecutive torrential rains persistent torrential rains blocking high trough cold front |
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