| 2013年浙江两次汛期暴雨过程对比分析 |
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| 引用本文： | 钱卓蕾,郭品文.2013年浙江两次汛期暴雨过程对比分析[J].大气科学学报,2016,39(2):253-259. |
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| 作者姓名： | 钱卓蕾 郭品文 |
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| 作者单位： | 浙江省绍兴市气象局, 浙江 绍兴 312000;南京信息工程大学 大气科学学院, 江苏 南京 210044 |
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| 基金项目： | 中国气象局气候变化专项项目(CCSF201535) |
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| 摘 要： | 利用NCEP/NCAR再分析资料,对2013年4月29日(4.29)和6月6日(6.6)浙江两次汛期暴雨的天气形势场、热力动力和水汽条件进行对比分析,研究浙江暴雨的机理,为暴雨预报提供依据。结果表明:1)4.29暴雨影响系统高层为西风槽、低层为低涡;6.6暴雨高低层影响系统均为低涡。2)4.29暴雨高空西风急流强,垂直方向上存在正向环流圈,低层辐合对应高层辐散;6.6暴雨高空西风弱,垂直方向上无明显环流圈,散度场分布较复杂。3)4.29暴雨主要水汽来源为孟加拉湾、南海-西太平洋;6.6暴雨主要水汽来源为孟加拉湾、南海-西太平洋和东海。4)4.29暴雨过程中锋区呈东西走向,有较强冷空气侵入,而6.6暴雨过程中锋区呈东南-西北走向,只有较弱冷空气侵入。
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| 关 键 词： | 暴雨 低涡 西风急流 湿位涡 |
| 收稿时间： | 2014/2/21 0:00:00 |
| 修稿时间： | 2014/5/1 0:00:00 |
Comparative analysis of two torrential rainstorms that occurred in Zhejiang in 2013 |
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| QIAN Zhuolei and GUO Pingwen.Comparative analysis of two torrential rainstorms that occurred in Zhejiang in 2013[J].大气科学学报,2016,39(2):253-259. |
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| Authors: | QIAN Zhuolei and GUO Pingwen |
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| Institution: | Shaoxing Meteorological Office, Shaoxing 312000, China;School of Atmospheric Sciences, Nanjing University of Information Science & Technology, Nanjing 210044, China |
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| Abstract: | Rainstorms in Zhejiang mainly occur in the flood season(February-October),during which heavy rainfall is common.The focus of the present study was two flood season rainstorm processes that occurred in Zhejiang in 2013,one belonging to the heavy spring rains hereafter referred to as the 4.29 rainstorm,based on its date of occurrence(29 April 2013) and the other being a typical Mei-yu rainstorm(hereafter referred to as the 6.6 rainstorm,using the same notation as previously mentioned).Based on NCEP analysis data,the circulation,thermal,dynamic and water vapor conditions of these rainstorm processes were analyzed.Through comparative analysis,the mechanistic similarities and differences were studied,providing a theoretical basis for further work on local rainstorm forecasting.The results can be summarized as follows:(1)During the 4.29 rainstorm,the high latitude circulation at the height of 500 hPa in East Asia was characterized by a western high and eastern low pattern.The main system of impact was the westerly trough at high latitudes together with a lower-level vortex,with stronger cold air,and a more southerly northward position of warm air,which induced southerly rain.A double block was present in the high-latitude circulation of the 6.6 rainstorm,and a low vortex was the main influence from the upper to lower levels,with weak cold air,and southwesterly flow further north,thus resulting in a northerly storm.(2)During the 4.29 process,an upper-level strong westerly jet existed,with a positive vertical circulation and low-level convergence corresponding to high-level divergence.During the 6.6 rainstorm,the high-level westerly wind was weak,with a more complex divergence field of a divergence zone during the early stage of precipitation from the near-surface to the lower levels,and a convergence zone in the middle levels,which transferred to weak convergence until the later stage of precipitation near the ground and with no apparent vertical circulation.(3)The source of water vapor for the two rainstorm processes was different:the water vapor for the 4.29 rainstorm process was mainly provided by the southwest jet stream,with the main source regions being the Bay of Bengal,the South China Sea and the western Pacific.The divergence distribution of water vapor flux was convergence in the lower layers,corresponding to upper-level scattered divergence.In the 6.6 rainstorm,the water vapor come from the southwest and southeast,with the main source regions being the Bay of Bengal,the South China Sea,the western Pacific,and the East China Sea.There was low-level divergence in the early stages of the divergence distribution of water vapor flux and convergence in the middle stages.In the later stages,however,there was consistent convergence under the middle level.The strengthened vapor flux convergence above the near-surface level played an obvious role in the rainfall intensity increasing.(4)An east-west oriented front with a strong cold air intrusion existed in the 4.29 process,while a northwest-southeast front with a weak cold air intrusion was apparent in the 6.6 process,both of which were advantageous for the release of baroclinic potential energy,and could promote convection development. |
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| Keywords: | torrential rain low vortex westerly jet moist potential vorticity |
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