李刚^1,,
李崇银^2,3,
晏红明^4,,,
江晓华⁵,
鞠永茂¹
1. 中国人民解放军 61741 部队, 北京 100094
2. 国防科技大学气象海洋学院, 南京 211101
3. 中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室, 北京 100029
4. 云南省气候中心, 昆明 650034
5. 西昌卫星发射中心, 四川西昌 615000

基金项目: 国家自然科学基金（U1902209，42030603），西南区域重点项目（2014-4）资助


详细信息

作者简介: 李刚, 男, 1983年生, 博士, 主要从事天气及气候变化研究.E-mail:ligang.1983@163.com

通讯作者: 晏红明, 女, 研究员, 主要从事季风气候研究.E-mail:y-hm@netease.com

中图分类号: P461

收稿日期:2020-02-29
修回日期:2020-07-07
上线日期:2020-11-05

The relationships of mid-summer rainfall over North China with North Pacific Decadal Oscillation and South Pacific Decadal Oscillation and their possible physical mechanisms

LI Gang^1,,
LI ChongYin^2,3,
YAN HongMing^4,,,
JIANG XiaoHua⁵,
JU YongMao¹
1. Unit 61741 Troops of PLA, Beijing 100094, China
2. Meteorological and Oceanography College, National University of Defense Technology, Nanjing 211101, China
3. State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
4. Yunnan Climate Center, Kunming 650034, China
5. Xichang Satellite Launch Center, Sichuan Xichang 615000, China


More Information

Corresponding author: YAN HongMing,E-mail:y-hm@netease.com

MSC: P461

--> Received Date: 29 February 2020
Revised Date: 07 July 2020
Available Online: 05 November 2020


摘要
摘要:利用降水、大气环流和海表温度等多种再分析资料和偏相关方法，研究了1951—2007年南太平洋年代际振荡（SPDO）和北太平洋年代际振荡（即PDO，本文称为NPDO）分别与华北盛夏（7—8月）降水在年代际时间尺度上的关系及其可能物理机制.结果表明：在去除SPDO和NPDO的相关性之前，它们与华北盛夏降水的关系均偏弱；但在去除两者相关性之后，SPDO（NPDO）与华北盛夏降水存在显著正（负）相关关系.去除两者相关性之后，当SPDO处于正位相时，热带西北太平洋海温异常显著偏暖，这将在对流层中下层从热带西太平洋—东亚沿岸激发出"气旋-反气旋-气旋"的负位相东亚—太平洋型遥相关（EAP）波列，该波列导致东亚夏季风异常增强，有利于低纬地区水汽输送至华北地区，从而使得华北盛夏降水异常偏多，反之，当SPDO处于负位相时，华北盛夏降水异常将偏少；对NPDO来说，当其处于正位相时，不仅热带西北太平洋异常显著偏冷，而且印度洋大部分海温异常显著偏暖，在两者共同作用下，对流层中下层从热带西太平洋—东亚沿岸出现"反气旋-气旋-反气旋"的正位相EAP波列，这将引起东亚夏季风异常减弱，不利于低纬地区水汽输送至华北地区，华北盛夏降水异常因此减少，反之，当NPDO处于负位相时，华北盛夏降水异常将偏多.
关键词: 北太平洋年代际振荡/
南太平洋年代际振荡/
华北盛夏降水/
东亚夏季风

Abstract:Using multiple reanalysis datasets and the partial correlation method, the relationships of South Pacific Decadal Oscillation (SPDO) and North Pacific Decadal Oscillation (PDO, called NPDO in this paper) with the mid-summer rainfall over North China on the decadal timescale and the related physical mechanisms are investigated. The results show that the relationships of SPDO and NPDO with mid-summer rainfall over North China are insignificant before removing the interdependence between the SPDO and NPDO. However, after removing the interdependence, there is significant positive (negative) relationship between SPDO (NPDO) and mid-summer rainfall over North China. The corresponding mechanisms are further examined. It is suggested that the positive phase of SPDO is associated with significantly warm sea surface temperature anomalies (SSTA) over the tropical northwestern Pacific, which would excite a negative East Asia-Pacific (EAP) pattern. The negative EAP pattern can induce a strengthened East Asian summer monsoon (EASM), which favors moisture transport from the low-latitude region to North China, leading to an anomalous more rainfall over North China, and vice versa. For the positive phase of NPDO, besides significantly cold SSTA over the tropical northwestern Pacific, significantly warm SSTA appears over most of Indian Ocean. Under the influence of SSTA over these two regions, a positive EAP pattern appears from the tropical northwestern Pacific to East Asia, inducing a weakened EASM, which is unfavorable for moisture transport from the low-latitude regions to North China, and thus anomalous less rainfall occurs over North China, and vice versa.
Key words:North Pacific Decadal Oscillation (NPDO)/
South Pacific Decadal Oscillation (SPDO)/
Mid-summer rainfall over North China/
East Asian summer monsoon



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