| 大陆高压对强热带风暴碧利斯内陆强降水影响 |
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| 引用本文： | 程正泉,陈联寿,李英.大陆高压对强热带风暴碧利斯内陆强降水影响[J].应用气象学报,2013,24(3):257-267. |
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| 作者姓名： | 程正泉 陈联寿 李英 |
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| 作者单位： | 1.区域数值天气预报重点实验室，广州 510080 |
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| 基金项目： | 国家重点基础研究发展计划项目(2009CB421504)，国家自然科学基金项目（40975032,41275066）,广东省气象局科技创新团队（201101） |
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| 摘 要： | 强热带风暴碧利斯 (0604)(简称碧利斯) 登陆后造成极其严重的灾害。对该次强降水过程诊断分析发现，除强盛的西南季风外，深厚的大陆高压也起着重要作用。自高层向低层逐渐加强的大陆高压，其东南侧深厚的偏东北气流，与碧利斯登陆后西北象限的东北风相叠加，配合强盛的西南季风，使得碧利斯残涡以及槽区得以长时间维持。涡度收支表明:长时间维持的台风槽，其低层强烈的辐合效应，对暴雨区低涡发展作用显著，致使中尺度对流系统不断发展而造成内陆连续强降水。数值试验表明:在强盛西南季风背景下，大陆高压的增强东伸，不仅能够提供高空强辐散，而且能增强碧利斯西北象限东北风，使得登陆后减弱的碧利斯残涡和台风槽得以长时间维持，致使内陆暴雨区各层涡度增加而导致暴雨维持与增幅。
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| 关 键 词： | 强热带风暴碧利斯 (0604) 强降水 大陆高压 涡度收支 |
| 收稿时间： | 8/9/2012 12:00:00 AM |
Influences of Continental High on Inland Torrential Rain Associated with Severe Tropical Storm Bilis (0604) |
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| Affiliation: | 1.Key Laboratory of Regional Numerical Weather Prediction, Guangzhou 5100802.Guangzhou Central Meteorological Observatory, Guangzhou 5100803.Chinese Academy of Meteorological Sciences, Beijing 100081 |
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| Abstract: | The remnant vortex of severe tropical storm Bilis (0604) endures over land for a few days, results in a large range of torrential rain over South China and leads to a calamity after it lands in Fujian Province on 14 July 2006. Many studies are carried out and reveal the crucial effect of low level southwesterly monsoon jet to the extreme rain event. But the influence of the continental high on the torrential rain is also worth being discussed. The analysis of circulation shows that during the torrential rain process associated with Bilis, the continental high at upper level strengthens, moves eastwards, and stretches downwards to the low level after Bilis makes landfall, which strengthens the northeasterly stream at the southeastern side of the continental high. When Bilis moves westwards, the northeasterly stream at the low and middle levels in the northwestern quadrant of Bilis, overlapping with that southeast to the continental high, is strengthened and increases the transfer of water vapor and instability energy to the inland, which is favorable to the maintenance of the remnant low and the typhoon trough. The vorticity above the inland rainstorm area remains high during the process. The budget shows that it is the long existing remnant vortex and typhoon trough whose intense convergence at the low level produces a large amount of vorticity, triggers the successive development of MCS and results in the continuous heavy rain. The contribution of the continental high is to help the maintenance of the remnant low and the typhoon trough, and to enlarge the horizontal advection of vorticity at the upper level. And a set of numerical sensitivity experiments reveals that, based on the background of strong southwestern monsoon, the intensification and eastward stretch of the continental high not only forces Bilis to move southwestwards, but also provides strong divergence at upper level over Bilis. Besides, the continental high influences the intensity and the distribution of heavy rain. The endurance of the remnant vortex and the typhoon trough, due to the strong low level southwesterly monsoon jet and the continental high, enhances the intensification of vorticity above the inland rainstorm area and the occurrence of torrential rain. And in the sensitivity experiment of weakened continental high, the northeasterly winds in the northwestern quadrant of Bilis become weakened and the transfer of water vapor to the inland rainstorm area and the vorticity decrease accordingly, which leads to the northward movement of rain bands and the decline of rain intensity with the decrease of the 24 h rainfall maximum in the inland by 1/3, compared with the control experiment. |
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| Keywords: | severe tropical storm Bilis(0604) torrential rain continental high vorticity budget |
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