双月刊

ISSN 1006-9895

CN 11-1768/O4

华南冬季强降水及高、低纬两支波列的协同影响
作者:
作者单位:

中山大学大气科学学院

作者简介:

通讯作者:

基金项目:

国家自然科学基金


The Cooperation of High and Low Latitudes-Wave Trains in the occurrence of Extreme Winter Precipitation over South China
Author:
Affiliation:

Sun Yat-Sen University

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
    摘要:

    采用1979~2015年ERA-Interim再分析资料和中国756个站点的逐日降水观测资料,利用百分位法定义了华南冬季强降水事件,通过聚类分析发现中国冬季强降水的中心主要集中在5个地区:长江中下游地区、华南中西部、华南东南部、淮河流域以及中国西南部。为了揭示华南南部大范围强降水的成因,对比分析了由西南地区自西向东移动至东南沿海的东移型强降水事件与西南地区局地型强降水事件。结果表明,南支槽槽前的暖湿气流与冷空气活动的强弱对峙是触发以及维持这两类强降水的关键。在局地型强降水中,活跃的冷空气活动抑制了南支槽的发展和东扩,强降水局限于西南地区;对于东移型强降水,由于冷空气活动偏弱,南支槽槽前西南暖湿气流东扩,降水落区随之东移。高纬度波列与南亚急流波列的协同作用是影响冷、暖气流相对强弱的关键环流系统。当高纬度波列与南亚急流波列同步发展时,冷、暖空气均较强形成强烈对峙,强降水主要局限在西南地区;当高纬度波列活动超前于南亚急流波列,冷空气活动与南支槽的加深错开,强降水可持续并东移,影响较大范围。

    Abstract:

    By using the ERA-Interim reanalysis data and daily precipitation observation from 756 stations over China, the extreme winter precipitation over South China during 1979-2015 are identified. They could be classified into five groups according to their spatial distribution via k-means clustering method. That is, the extreme precipitation occurs over the Yangtze River valley, central South China, southeastern South China, Huaihe River Valley and Southwest China. To disclose the causes of the widespread extreme winter precipitation over South China, the extreme precipitation with an eastward migration from Southwest China to the coastal Southeast China have been further analyzed, by comparing with that occurs locally over Southwest China. The results show that the main differences in the trigger and maintenance mechanisms of winter extreme precipitation between the local and eastward migrating cases, are the confliction between warm and moist advection by India-Burma trough and intensity of cold air activity. For the local cases, active cold air activity inhibits the development of India-Burma trough, resulting in the constraint of extreme precipitation over Southwest China. On the contrary, the warm and moist advection by India-Burma trough move eastward continuously in the eastward migration cases along with weak cold air activity. The cooperation of high-latitude wave train and South Asian jet wave train is crucial to the confliction between cold air activity and warm advection. When these two wave trains develop synchronously, the cold air activity over South China will be strong and the warm advection from the Bay of Bengal will be confined over Southwest China, so does the resulting precipitation. However, when the high-latitude wave train developed ahead of South Asian jet wave train, and the cold air activity is weak when the India-Burma trough is enhanced by the South Asian jet wave train, the warm advection from the Bay of Bengal could move eastward continuously, resulting in the eastward migration of precipitation from Southwest China to the coastal Southeast China.

    参考文献
    相似文献
    引证文献
引用本文
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2020-12-12
  • 最后修改日期:2021-02-26
  • 录用日期:2021-05-07
  • 在线发布日期:
  • 出版日期: