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DOI | 10.1007/s00382-016-3304-3 |
Understanding positive feedback between PNA and synoptic eddies by eddy structure decomposition method | |
Zhou, Fang1; Ren, Hong-Li2,3; Xu, Xiao-Feng2; Zhou, You1 | |
2017-06-01 | |
发表期刊 | CLIMATE DYNAMICS
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ISSN | 0930-7575 |
EISSN | 1432-0894 |
出版年 | 2017 |
卷号 | 48期号:11 |
文章类型 | Article |
语种 | 英语 |
国家 | Peoples R China |
英文摘要 | In the upper troposphere during winter, positive synoptic eddy (SE) feedback plays an indispensible role in maintaining the Pacific-North American (PNA) pattern that dominates climate variability on inter-annual timescales over the North Pacific and downstream regions. This study shows that the eddy forcing, induced by eddy-vorticity (EV) fluxes, is not only in-phase with, but also downstream to the PNA pattern in terms of its northeast Pacific lobe. We employ the eddy structure decomposition method to understand such an observed PNA-SEs feedback, and propose a kinematic mechanism that can depict dynamical processes associated with the eddy structure change and its induced positive eddy feedback relative to the PNA flow pattern. With this method, the winter-mean PNA-related SE structures are separated into climatological (basic) and anomalous SE structures, and these two parts can be used to represent the changes in SE structure in a statistical sense and then to calculate the EV fluxes in order to further elucidate the feedback mechanism. It is demonstrated that, on one hand, the winter-mean PNA flow tends to systematically deform the structures of SEs and induce anomalous EV fluxes, and these winter-mean EV fluxes primarily converge into the PNA cyclonic center, which, in return enhances the PNA flow. On the other hand, the PNA-related northeast Pacific flow is featured by a stronger zonal wind shear in the east than the west, which can induce larger zonal-slanting eddy structure change and then stronger meridional EV fluxes that converge to form downstream feedback. This kinematic mechanism may help to deeply understand the dynamical eddy feedback between the low-frequency PNA flow and high-frequency SEs. |
英文关键词 | Pacific-North American (PNA) pattern Positive eddy feedback Downstream feedback Eddy structure decomposition Meridional eddy fluxes Zonal eddy fluxes |
领域 | 气候变化 |
收录类别 | SCI-E |
WOS记录号 | WOS:000402122200022 |
WOS关键词 | LOW-FREQUENCY VARIABILITY ; 500-MB HEIGHT FLUCTUATIONS ; NORTHERN-HEMISPHERE WINTER ; MIDLATITUDE STORM TRACKS ; SHORT-TIME SCALES ; FLOW INTERACTION ; ANNULAR MODE ; TELECONNECTION PATTERNS ; CIRCULATION ANOMALIES ; PART I |
WOS类目 | Meteorology & Atmospheric Sciences |
WOS研究方向 | Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/35346 |
专题 | 气候变化 |
作者单位 | 1.Nanjing Univ Informat Sci & Technol, Nanjing 210044, Jiangsu, Peoples R China; 2.China Meteorol Adm, Natl Climate Ctr, Lab Climate Studies, 46 Zhongguancun Nandajie St, Beijing 100081, Peoples R China; 3.Joint Ctr Global Change Studies, Beijing, Peoples R China |
推荐引用方式 GB/T 7714 | Zhou, Fang,Ren, Hong-Li,Xu, Xiao-Feng,et al. Understanding positive feedback between PNA and synoptic eddies by eddy structure decomposition method[J]. CLIMATE DYNAMICS,2017,48(11). |
APA | Zhou, Fang,Ren, Hong-Li,Xu, Xiao-Feng,&Zhou, You.(2017).Understanding positive feedback between PNA and synoptic eddies by eddy structure decomposition method.CLIMATE DYNAMICS,48(11). |
MLA | Zhou, Fang,et al."Understanding positive feedback between PNA and synoptic eddies by eddy structure decomposition method".CLIMATE DYNAMICS 48.11(2017). |
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