干旱气象

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长江下游地区6—9月暴雨过程延伸期预报的探索

孙国武1,2李震坤2陈伯民2信飞2梁萍2   

  1. 1.中国气象局兰州干旱气象研究所,甘肃兰州730020;2.上海市气候中心,上海200030
  • 出版日期:2017-10-31 发布日期:2017-10-31
  • 通讯作者: 李震坤,E-mail:lizhenk@yeah.net。
  • 作者简介:孙国武(1937—),男,研究员,主要从事干旱气候、大气低频振荡和季风等研究. E-mail:guowusun@163.com。
  • 基金资助:

    中国气象局公益性行业(气象)科研专项(GYHY201306030)、国家自然科学基金项目(41205060)“江淮梅雨季节10~30天延伸期降水过程可预报性研究”共同资助

Exploration of Extended Range Forecast for Rainstorm Process from June to September in the Lower Reaches of the Yangtze River

SUN Guowu 1,2, LI Zhenkun2, CHEN Bomin2, XIN Fei2, LIANG Ping2   

  1. 1. Lanzhou Institute of Arid Meteorology, CMA, Lanzhou 730020, China;
    2. Shanghai Climate Center, Shanghai 200030, China
  • Online:2017-10-31 Published:2017-10-31

摘要:

通过使用低频天气图上大气低频系统(低频气旋和低频反气旋),分析上海地区(长江下游)的暴雨(≥50 mm)过程发生时段低频系统的地理位置和相互配置,并根据近年75次暴雨过程中每次暴雨过程的低频系统演变,归纳合成得到低频预测模型:一种是长江下游北—西北方为低频反气旋,南—东南方是低频气旋(A型);另一类与A型相反,北—西北方是低频气旋,南—东南方是低频反气旋(B型)。最后分析了低频预测模型的物理意义,表明暴雨发生期有西北向东南同时有东南向西北的低频波列(位势高度和水汽通量)在30°N、120°E附近汇合,引起降水。同时低频系统的维持也与扰动动能有关。

关键词: 低频气旋, 低频反气旋, 暴雨过程, 水汽通量

Abstract:

The geographical position and configuration of low-frequency systems including low-frequency cyclones and anticyclones during rainstorm processes (≥50 mm) were analyzed by using low-frequency synoptic map in Shanghai or the lower reaches of the Yangtze River (LRYR). Then two low-frequency prediction models were proposed and applied in operation based on the evolution of low-frequency systems of 75 rainstorm processes in recent years. One is that low-frequency anticyclone exists in the north-northwest of LRYR and low-frequency cyclone exists in the south-southeast (type A), the other is the opposite of type A, which means low-frequency cyclone stands in the north-northwest of LRYR and low-frequency anticyclone exists in the south-southeast. Finally, the physical meaning of low-frequency prediction models was discussed and the results demonstrated that the rainstorms occurred when low-frequency wave trains of geopotential height and water vapor flux from northwest to southeast and southeast to northwest converged over the location of 30°N, 120°E and its vicinity region. And the maintenance of low-frequency systems had relation with the intensity of perturbation kinetic energy.

Key words:  low-frequency cyclone, low-frequency anticyclone, rainstorm process, water vapor flux

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