| 一次持续性强暴雨过程的平均特征 |
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| 引用本文： | 陈忠明,闵文彬,高文良,何光碧.一次持续性强暴雨过程的平均特征[J].应用气象学报,2006,17(3):273-280. |
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| 作者姓名： | 陈忠明 闵文彬 高文良 何光碧 |
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| 作者单位： | 成都高原气象研究所, 成都 610071 |
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| 基金项目： | 国家高技术研究发展计划(863计划) |
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| 摘 要： | 2004年9月2—6日四川盆地中东部发生了一次持续性强暴雨过程。利用时间平均合成分析方法对强暴雨维持期间 (9月3日20:00—5日08:00, 北京时) 的探测资料进行合成平均, 再对合成平均资料做诊断分析, 以揭示持续性强暴雨过程持续期的平均特征。诊断分析显示, 台风西进导致稳定的环流以及中低层大量的水汽输送为暴雨持续提供了背景条件。在时间平均流场上, 与暴雨相联系的中尺度系统十分显著, 它在对流层中低层表现为准东西向的中尺度辐合带, 在对流层高层表现为中尺度辐散带, 两者垂直耦合为深厚系统。此外, 在暴雨持续期间, 对流层低层大气运动表现出强烈的非平衡特征, 这种非平衡的动力强迫作用支撑着低层强辐合的维持。
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| 关 键 词： | 持续性暴雨 非平衡性质 能量锋与低空急流 |
| 收稿时间： | 2005-06-09 |
| 修稿时间： | 2006-01-07 |
Mean Features of Continuing Heavy Rain Process in Sichuan Basin During 2-6 September 2004 |
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| Chen Zhongming,Min Wenbin,Gao Wenliang,He Guangbi.Mean Features of Continuing Heavy Rain Process in Sichuan Basin During 2-6 September 2004[J].Quarterly Journal of Applied Meteorology,2006,17(3):273-280. |
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| Authors: | Chen Zhongming Min Wenbin Gao Wenliang He Guangbi |
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| Institution: | Chengdu Institute of Plateau Meteorology, Chengdu 610071 |
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| Abstract: | The persistent precipitation which lasts a long period of time, concentrates on an area and induces the most serious disasters is the essential concern of the researchers and weather reporters. Previous researches have mainly paid close attention to the mechanism of the formation and development of heavy rain, but not attached much importance to the analysis of mean features of heavy rain process.A continuing heavy rain process occurs in Sichuan Basin during 2—6 September 2004. The composite analysis is used in order to analyze mean features of this heavy rain process. The composite technique of meteorological data is as the follow: , where F (p, k) represents mean value of meteorological factor at k-station on p-isobaric surface; i represents time level of observation; p represents depth of isobaric surface; k is the ordinal number of meteorological station. Diagnostic analysis on time averaging values F (p, k) of meteorological factors from 20:00 on 3 September to 08:00 5 September 2004 is made. The results show that: ① "Sanda" typhoon moves westward, causing the mainland high cell stable and meanwhile the cold trough moving southeastward along the northeast side of the Tibetan Plateau blocking on the north of Sichuan Basin. The cold trough forms and dissipates repeatedly over this area, creating a favorable environment for the persistent torrential rain. ② The divergence intensity is higher than the vorticity in lower troposphere. Atmospheric motion is characterized by convergence of air current. The relationship between them is quite the contrary in upper troposphere. ③ The vertical coupling of meso-scale convergence belt in low layer with divergence belt in high layer constructs a meso-scale system with long lifespan and deep upward current. ④ The sources of watervapour over heavy rain area are the South China Sea and the Bay of Bengal. The moisture flux transferring to heavy rain area from the South China Sea is more than the Bay of Bengal, but there is not significant difference between them. To analyze the intensity of the moisture transfer from different sources contributes to the reveal of the moisture source of continuing heavy rain process. ⑤ The coupling between meso-scale convergence belt in lower troposphere and meso-scale divergence belt in upper troposphere constructs a deep and long life meso-scale system. It directly contributes to the maintenance of heavy rain. ⑥ Atmospheric motion is strongly unbalanced during heavy rain. Force faction of the unbalance leads to the maintenance of the strong convergence in low layer and is also the main dynamic factor leading to the continuing heavy rain. |
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| Keywords: | continuing heavy rain unbalanced force of atmospheric motion low layer jet and energy front |
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