J4 ›› 2009, Vol. 27 ›› Issue (3): 254-262.

• 论文 • 上一篇    下一篇

河北中南部一次大暴雨个例的成因诊断

马鸿青1,2丁治英   

  1. 1.南京信息工程大学大气科学学院,江苏 南京 210044;2.河北省保定市气象局,河北 保定 071000
  • 收稿日期:2009-08-03 修回日期:2009-09-01 出版日期:2010-09-30 发布日期:2009-09-30

Diagnostic Analysis of a Heavy Rain in South Central ofHebeiProvince

 MA Hong-Jing1,2, DING Chi-Yang1   

  1. (1. College ofAtmospheric Sciences, Nanjing University ofInformation Science& Technology, Nanjing210044, China;2. BaodingMeteorologicalBureau ofHebeiProvince, Baoding071000, China)
  • Received:2009-08-03 Revised:2009-09-01 Online:2010-09-30 Published:2009-09-30
  • About author:马鸿青(1976-),河北保定人,在读硕士,工程师,主要从事短期预报及研究.E-mail:mhqgy000@yahoo.com.cn

摘要:

利用NCEP 1°×1°再分析资料和常规资料,分析了一次河北中南部罕见短时特大暴雨的环流背景,计算了暴雨发生过程的干位涡、湿位涡值以及暴雨区域垂直螺旋度的大小。然后利用这些物理量从动力、热力学方面对河北暴雨进行综合分析。结果发现: 500 hPa干位涡正压项能较好地表征冷空气和辐合区的强度和移动方向,斜压项负值由小到大引发降水强度的增加,斜压项负值的减小预示着降水的减弱。在此暴雨个例中,强对流发生区域与湿位涡异常的移动方向有较好的相关性,强对流出现在湿位涡移动方向前部的等值线密集区,且短时暴雨靠近零线一侧。正MPV1异常与负MPV2
异常相叠置区域,即大气对流稳定时,因垂直涡度得到发展,激发出强对流。低层螺旋度正值中心的出现并增大,预示着强对流的发生,同一经度相邻正负螺旋度中心的存在有利于正螺旋度区域暴雨强度的增大。

关键词: 暴雨, 干位涡, 湿位涡, 螺旋度
     

Abstract:

Based on observed data andNCEP reanalysis data, the circulation background ofa heavy rain occurred in south centalofHebei Province onMay 9, 2009 was analyzed. By calculating the dry andmoistpotentialvorticity (PV andMPV) and the verticalhelicity, the characteristics ofPV, MPV and helicity of the rainstorm were researched. The results show that the dry potentialvorticity at 500 hPa could better reflectboth surface cold airmoving direction and convergence intensity, the rain intensity became largerwith PV2 increase and weakenedwith PV2 decrease. For this rainstorm case, the zone of strong convectionwas better related to the abnormalmoving direction ofmoistpotential vorticity at850 hPa, and the rainstorm occurred in the isoline dense area in front of moistpotentialvorticity. At the overlapping area of abnormalMPV1 andMPV2, the strong convectionwas easily triggered.The appearance and enlarging of positive center ofhelicity at lower level showed in advance the breaking out of rainstorm. The close negative and positive centers of helicity on the same longitudewas in favor of amplification ofheavy rain in positive helicity region.

Key words: rainstorm, dry potential vorticity, moistpotential vorticity, helicity

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