双月刊

ISSN 1006-9895

CN 11-1768/O4

东亚副热带季风季节循环年际变化对华北夏季降水的影响
作者:
作者单位:

中国气象科学研究院

作者简介:

通讯作者:

基金项目:

国家自然科学基金(41830969),中国气象科学研究院科技发展基金(2020KJ012)


The interannual variation of Annual Cycle of the East Asian Subtropical Monsoon and its Impact on Summer Rainfall in North China
Author:
Affiliation:

Chinese Academy of Meteorological Sciences

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:

    由于受到东亚副热带夏季风复杂变化的影响,华北夏季降水的年际变化预测一直是我国季节气候预测的难点。本文采用1979-2020年中国站点日降水数据和CRA-40大气再分析资料,通过谐波分解、MV-EOF分析等统计方法,研究了东亚副热带季风季节循环年际变化对华北夏季降水的影响。结果表明:在气候态上,华北降水相关的季节循环在850hPa风场上主要表现为东南风和西南风主导两种模态,其中,西南风主导的降水在7月初达到峰值,而东南风主导的降水在7月底达到峰值。在年际尺度上,季节循环前两个主模态中的华北降水虽然表现为区域一致性变化特点,但在夏季先后受到西南风和东南风的影响。通过对季节循环华北夏季风雨季的开始时间(P1)、峰值时间(P2)、结束时间(P3)、持续时间(D)和振幅(A)与夏季(6-8月)降水年际变化分析,我们发现东南风主导的季节循环的开始时间、结束时间、振幅与华北夏季降水异常呈显著正相关,而峰值时间和持续时间与华北夏季降水异常呈负相关。西南风主导的季节循环的峰值时间、结束时间和振幅与华北夏季降水异常均呈显著正相关。其中,东南风季节循环的位相(P1、P2、P3)变化与夏季西南风的强度有关,而其幅度(A)变化主要取决于东南风的强度。由于东南风主导的夏季降水开始于每年的4-5月份,其建立的早晚为6-8月夏季降水的季节预测提供了一个新的参考指标。

    Abstract:

    Owing to the complicated change of East Asian summer monsoon and chaotic influence, the accurate forecast of summer rainfall anomalies in North China is a great challenge. To understand the origin of summer rainfall anomalies in this region, we applied the daily observed rainfall with CRA-40 atmospheric reanalysis, harmonic and MV-EOF analysis to examine the impact of annual cycle of East Asian subtropical summer monsoon (EASSM) on the summer rainfall anomalies in North China during 1979-2020. Our results show that, in climatology, the rainfall related seasonal cycle of winds at 850hPa in North China exhibits two dominant modes, characterized by the southwestly and southeastly, which reaches their peak in early and late July, respectively. Although the rainfall in North China revealed by the first two modes exhibits consistent changes on interannual scale, it is successively affected by southwestly wind and southeastly wind anomalies. Based on the analysis of the onset date (P1), peak date (P2), retreat date (P3), duration (D) and amplitude (A) of the annual cycle modes during the rainy season and the summer monsoon rainfall (from June to August) anomalies in North China, We found that the onset and retreat date, and the amplitude of annual cycle modes dominated by southeast wind are significantly positively correlated with the summer rainfall anomalies in North China, while the peak date and duration are negatively correlated with the summer rainfall anomalies in North China. Its phases (P1, P2, P3) variation are related to the intensity of southwest wind in summer, while the amplitude (A) variation mainly depends on the intensity of southeast wind. The peak date, retreat date and amplitude of the second annual cycle mode, dominated by southwestly wind shows a significantly positive correlations with summer rainfall anomaly in North China. Since the summer rainfall dominated by the southeast wind starts from April to May, the establishment of the EASSM related to the rainfall in North China provides a new index for the seasonal forecast of summer rainfall in North 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:2021-09-26
  • 最后修改日期:2021-11-17
  • 录用日期:2022-01-18
  • 在线发布日期: 2022-01-27
  • 出版日期: