干旱气象

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河西干旱区短时强降水过程的中尺度分析

李文莉王宝鉴吉惠敏狄潇泓   

  1. 兰州中心气象台,甘肃 兰州 730020
  • 收稿日期:2013-01-08 出版日期:2013-07-10 发布日期:2013-04-02
  • 作者简介:李文莉(1977 - ),女,汉族,甘肃靖远人,工程师,主要从事短期、短时临近天气预报及相关研究. E - mail:281531902@ qq. com
  • 基金资助:

    西北东部短历时强降水和冰雹天气的预报预警关键技术集成应用(CMAGJ2013Z09)及中国气象局预报员专项“‘510’岷县雹洪
    天气中尺度分析”(CMAYBY2013 -072)共同资助
     

Mesoscale Analysis of Heavy Rainfall Process in Hexi Arid Area in Gansu Province

LI Wenli,WANG Baojian,JI Huimin,DI Xiaohong   

  1. Lanzhou Meteorological Central Observatory,Lanzhou 730020,China
  • Received:2013-01-08 Online:2013-07-10 Published:2013-04-02

摘要:

运用中尺度天气分析技术,对河西西部干旱区3 次短时强降水过程从高空、地面的影响系统、水汽条件、抬升条件、不稳定条件、高低层风场配置等方面进行了对比分析,找出了3 次过程的相似点与不同之处,结果表明:500 hPa 新疆有低压槽东移,低槽前部甘肃河东到张掖为高压脊或者歪脖子高压,青海高原有低涡或者切变线,相应的低层也为低槽、切变线或者低涡,地面有冷锋、辐合线配合的环流形势是河西西部短时强降水产生的关键,高空急流(200 hPa)或者高空显著流线入口区右侧、地面露点温度Td >10 ℃的高湿区、低层绝对湿度比湿>6 g/ kg,中层500 hPa 处在显著湿区、700 hPa 假相当位温高能舌、K 指数>30 ℃,CAPE 值也明显增大为产生短时强降水提供了有利条件,最后建立了河西西部干旱区短时强降水中尺度天气分析概念模型。
 

关键词: 河西西部, 干旱区, 短时强降水, 中尺度天气图, 对比分析

Abstract:

Based on mesoscale weather analysis technology,the influencing systems of high altitude and surface layer,water vapor conditions,uplifting condition,unstable condition,high and low layer wind field configuration of three short - term rainfall processes in the west of Hexi arid area were analyzed comparativel. The results show that there was trough moving eastward on 500 hPa in Xinjiang,and in front of the low trough there were the wry neck high pressure or ridge of high pressure from Hedong to Zhangye of Gansu province.A low vortex or shear line existed on Qinghai Plateau,at the same time,low trough,shear line or low vortex existed on lower layer,and there was a cold front,convergence line on the ground,which was the key factor for short - time strong rainfall in western
Hexi. High altitude jet stream ( 200 hPa) or high altitude significant streamline entry area on the right side,and high humidity area with ground dew point temperature more than 10 ℃,the absolute specific humidity > 6 g /kg on the lower layer,500 hPa wet area,700 hPa significantly high energy tongue,K index more than 30 ℃,increasing CAPE value,these all provided favorable conditions for a short - time strong rainfall. Finally the mesoscale weather analysis conceptual model of short - time strong rainfall was established in arid western Hexi area.

Key words: the west of Hexi, arid area, short - term rainfall, mesoscale weather chart, comparative analysis

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