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华南前汛期夏季风降水开始日期的确定

  

  1. 1.甘肃省临夏州气象局,甘肃 临夏 730000;2.中国气象局气候研究开放实验室,北京 100081;3.兰州大学大气科学学院,甘肃 兰州 731100
  • 收稿日期:2014-05-23 出版日期:2015-04-30 发布日期:2014-07-31
  • 作者简介:马玉坤(1988- ),男,回族,甘肃临夏人,硕士研究生,助工,主要从事夏季风气候及短期天气预报等方面研究.E-mail:244314593@qq.com
  • 基金资助:

    亚洲区域海陆气耦合系统模拟及预测理论(2010CB950404)资助

The Start Date of Summer Monsoon Rainfall in Pre-flood Season in South China

  1. 1. Linxia Meteorological Bureau of Gansu Province, Linxia 731100, China;
    2. Laboratory for Climate Studies, China Meteorological Administration, Beijing 100081, China;
    3. College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
  • Received:2014-05-23 Online:2015-04-30 Published:2014-07-31

摘要:

华南前汛期降水包含锋面降水和夏季风降水,提高对这2种不同性质降水的认识及如何区分是非常重要的。本文利用NCEP/NCAR再分析资料,分析了华南不同性质降水期间大气特性的差异,并采用集合经验模态分解(EEMD)方法,自适应地提取假相当位温θse的调制年循环变量(MAC),得到华南前汛期夏季风降水开始日期的划分标准。结果表明,当某年θse的MAC>δ标准差时,南海夏季风推进至华南地区,夏季风降水开始。利用该标准划分的华南前汛期夏季风降水开始日期平均为5月第6候,且具有2~3 a、13~15 a的年际、年代际变化周期。进一步对比分析表明,此标准划分的结果基本合理。

关键词: 华南, 夏季风降水, 集合经验模态分解, 调制年循环, 假相当位温

Abstract:

The pre-flood season rainfall in South China is composed of the frontal precipitation and the summer monsoon precipitation. It is very important to raise awareness and distinguish these two types of precipitation. Based on the daily reanalysis data from NCEP/NCAR with 2.5°×2.5° resolution and daily precipitation at 35 meteorological stations in South China from 1961 to 2010, the differences of atmospheric property were analyzed in different rainfall period in South China. The modulated annual cycle (MAC) variable of potential pseudo-equivalent temperature(θse) was self-adaptively extracted by using ensemble empirical mode decomposition (EEMD) method, and the division standard of the start date of summer monsoon precipitation in pre-flood season in South China was obtained. The results showed that the South China Sea summer monsoon (SCSSM) pushed to the South China when the MAC of θse was greater than the standard deviation δ, which meant the beginning of summer monsoon precipitation. The average start date of summer monsoon rainfall in pre-flood season in South China was the sixth pentad in May, and had 2-3 years interannual periodic oscillation and 13-18 years decadal periodic oscillation. Further compared with some previous findings, the result of the EEMD method was reasonable.

Key words: South China;summer monsoon rainfall;Ensemble Empirical Mode Decomposition;Modulated Annual Cycle(MAC), potential pseudo-equivalent temperature

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