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| 改进的湿Q矢量分析方法及梅雨锋暴雨形成机制 | |
| 引用本文： | 岳彩军,董美莹,寿绍文,姚秀萍.改进的湿Q矢量分析方法及梅雨锋暴雨形成机制[J].高原气象,2007,26(1):165-175. |
| 作者姓名： | 岳彩军 董美莹 寿绍文 姚秀萍 |
| 作者单位： | 1. 中国气象局,上海台风研究所,上海,200030;中国气象局,台风预报技术重点开放实验室,上海,200030 2. 浙江省气象台,浙江,杭州,310021 3. 南京信息工程大学,大气科学系,江苏,南京,210044 4. 中国气象局培训中心,北京,100081 |
| 基金项目： | 国家自然科学基金项目(40405009,40075009,40205008)，上海市气象局科研开发项目(0301)共同资助 |
| 摘 要： | 利用实测暴雨资料,结合改进的MM4(MMM4)模式模拟输出的加密资料,分别利用改进的湿Q矢量(记为Q*)及改进的湿Q矢量分解(Partitioning),诊断分析了1991年7月5日20:00~6日20:00一次典型的江淮梅雨锋暴雨过程。结果表明,600hPaQ*矢量散度辐合区对同时刻地面降水的强度、落区及不均匀性有很好的指示作用。在整个梅雨锋暴雨过程中,Q*矢量散度辐散、辐合在垂直方向上是相间分布的,它所激发的次级环流可能是诱发梅雨锋暴雨产生的重要因素。进一步研究表明,改进的湿Q矢量分解比“总”Q*矢量更具有诊断意义,可将梅雨锋暴雨的垂直运动场进行有意义的尺度分离,更有利于梅雨锋暴雨的潜在物理机制的评估。在梅雨锋暴雨的不同阶段,对于垂直运动场而言,不同尺度的Q*矢量散度辐合场的强迫作用不同,有主、次之分。基于上述诊断分析结果,本文进而提出梅雨锋暴雨形成的可能物理机制,并给出其概念模式:由于初始大气中大尺度的水汽及垂直运动场的空间分布不均匀,从而造成了大尺度Q*矢量散度辐合,激发出次级环流,进而引发了中尺度Q*矢量散度辐合场的产生,最终产生次级环流,直接导致梅雨锋暴雨的发生。 |
| 关 键 词： | 改进的湿Q矢量 改进的湿Q矢量分解 梅雨锋暴雨 |
| 文章编号： | 1000-0534（2007）01-0165-11 |
| 修稿时间： | 2005-12-192006-06-20 |
Improved Wet Q Vector's Analytical Method and the Mechanism of Meiyu Front Rainstorm Genesis |
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| YUE Cai-jun,DONG Mei-ying,SHOU Shao-wen,YAO Xiu-ping.Improved Wet Q Vector''''s Analytical Method and the Mechanism of Meiyu Front Rainstorm Genesis[J].Plateau Meteorology,2007,26(1):165-175. | |
| Authors: | YUE Cai-jun DONG Mei-ying SHOU Shao-wen YAO Xiu-ping |
| Institution: | 1. Shanghai Typhoon Institute, China Meteorological Administration, Shanghai 200030, China;2. Laboratory of Typhoon Forecast Technique, China Meteorological Administration, Shanghai 200030, China ; 3. Meteorological Observatory of Zhejiang Province, Hangzhou 310021, China; 4. Department of Atmospheric Sciences, Nanj ing University of Information Science and Technology, Nanj ing 210044, China; 5. China Meteoeological Administration, Training Center, Beijing 100081, China |
| Abstract: | By means of the observed weather data and the intensive simulation product data by modifiedMM4 model,improved wet Qvector(Q*) and Q*vector partitioning,a typical Jiang-Huai Meiyu event beginning from 20:00 on 5 to 20:00 on 6 July 1991 is diagnosed in detail.The results show that the convergence field(CF) of Q* divergence(Q*D) at 600 hPa to precipitation intensity,occurring region and their inhomogeneities at same time have a good indicator activity.The divergence fields are alternately distributed in vertical direction with the related convergence ones throughout the rainstorm process,whereby the secondary circulation(SC) forcing is likely to be an important factor inducing Meiyu front heavy rainfall genesis(MFRG).Furthermore,the Q*vector partitioning has more important diagnostically function than that totalQ*,which leads to a meaningful scale separation of vertical motion(VM) corresponding to torrential rain and is thus more favorable for evaluating the potential physical mechanism for MFRG.For VM,CFs of Q*Dindicate different forcings from one phase to another of the rainstorm.Based on above,we depict a possible physical mechanismand provide a concept modefor MFRG:In original atmospheric state,the spatial inhomogeneities of large-scale vapor and VMmake for convergence of synoptic scale Q*Dfield,which,in turn,forces SC,leading to CFof mesoscale Q*Dsuch that the SCforcing results in MFRGgenesis. |
| Keywords: | Improved wet Qvector Improved wet Qvector partitioning Meiyu front rainstorm |
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