J4 ›› 2007, Vol. 25 ›› Issue (4): 5-11.

• 论文 • 上一篇    下一篇

“99. 6”梅雨锋暴雨模拟资料的诊断分析

王 文1 ,蔡晓军1 ,隆 霄2   

  1. 1. 南京信息工程大学大气科学学院,江苏 南京 210044; 2. 兰州大学大气科学学院,甘肃 兰州 730000
  • 收稿日期:2007-10-21 修回日期:2007-11-07 出版日期:2007-12-31 发布日期:2007-12-31
  • 作者简介:王文(1957 - ) ,男,甘肃会宁人,博士,教授,主要从事气候诊断和中尺度动力学方面的研究
  • 基金资助:

    干旱气象科学研究基金( IAM200610) ;国家自然基金重点项目(40633017)共同资助

A Model - Based Diagnostic Study of“99 . 6”Meiyu Fron t Rain storm

WANGWen1 , CA I Xiaojun1 ,LONG Xiao2   

  1. College of A tm ospheric Sciences, N anjing University of Inform ation & Technology, N anjing 210044, China;2. College of A tm ospheric Sciences, Lanzhou University, Lanzhou 730000, China
  • Received:2007-10-21 Revised:2007-11-07 Online:2007-12-31 Published:2007-12-31

摘要:

:利用非静力中尺度模式MM5V3的模拟资料对“99. 6”梅雨锋暴雨过程进行了对流动量输送(CMT)和视热源视水汽汇分析。CMT诊断分析表明,水平动量残差在切变低涡发展的不同阶段的作用是不同的,在中尺度低涡发生初期对流层低层动量残差çX主要是加速西南气流的北上;在对流层中层动量残差在槽后加速冷空气南下,在槽前加速西南暖湿气流北上,非常有利于东亚大槽的发展。在低涡切变线强烈发展时, 850 hPa的çX方向与发生阶段相反,此时西南气流受到了强烈的减速作用,同时500 hPa东亚大槽的前部和后部出现了减速气流的动量残差,槽后冷空气和槽前的暖湿气流都已经受到减速作用,此后低涡切变线逐渐衰减。低涡切变线发展到最强的阶段,强çX矢量几乎总是与强烈上升运动区相对应,能量转换E的水平分布表明,大尺度系统与中尺度系统之间的能量转换非常复杂,并不是简单的能量串级过程,但能量主要是从大尺度向次网格尺度转换。200 hPa动能转换E的带状分布非常清楚, E的正负大值中心分布在高空急流的2侧,表明高空急流在能量转换的过程中起到非常重要的作用。视热源和视水汽汇的诊断分析显示,强凝结潜热的释放与低涡的发展相伴随,但视热源只与β中尺度系统有明显的对应关系,视水汽汇有和视热源非常相似的分布特征。

关键词: 梅雨锋, 暴雨, MM5V3, CMT, 视热源, 视水汽汇

Abstract:

A model simulation of“99. 6”Meiyu Front rainstorm by nonhydrostatic mesoscale modelMM5V3 is analyzed in an effort to study the mechanism of theMeiyu front. The results of trajectories analysis show that four airstreams converge into the low vortex. On low levels, the southwest Jet and the northeast flow increased convergence on low levels as the low meso -α vortexwith shear line develop ing, and the westly Jet and the eastly Jet increased divergence on high levels. It is this collocation from low levels to high levels that urged meso -α low vortex to develop. The diagnosis of convective momentum transport (CMT) shows that, the budget residual X of the horizontalmomentum has different effects in different periods of the low vortex with the shear line: On low levels, X strengthened the southwest flow to north on the occurring stage, on middle levels, X accelerated northwest flow behind EastAsia Trough to north and also accelerated northwest flow ahead of EastAsia Trough to the south.All these were in favor of deepening the EastAsia Trough and mingling cold and warm air, and gave favorable conditions to p roduce rainstorm. On the develop ing period, X has the reverse direction with southwest flow, which p revented southwest flow to the north. At the same time, it decelerated the cold (warm) flow behind ( ahead of) the East Asia Trough. on the level of 500 hPa. The diagnosis of CMT on the violently develop ing period of the mesoscale system shows that strong X always related to the meso -β systemswhich brought intense ascendingmotions.While the shear line launched out, X has strong decelerating effects for southwest flow. The result of diagnosis also revealed that large - scale environment field has overt energy interconversion with subgrid scale systems on the intense develop ing period of the mesoscale system, and energy p rimarilywas transported to microscale systems. Furthermore, energy exchanges on high levels were closely with the location of Upper Jet. The diagnoses of apparent heat source indicate that releasing of strong latent heat of condensation concomitant with intense develop ing of the low vortex. Onlymeso -β systemsA and B have better relation with apparent heat source. The characters of apparentmoist sink are analogous to that of apparent heat source.

Key words: Meiyu front, MM5V3, CMT, apparent heat source, moist sink

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