DOI: 10.1175/JCLI-D-15-0645.1
Scopus记录号: 2-s2.0-84987957323
论文题名: Pacific influences on tropical Atlantic teleconnections to the southern hemisphere high latitudes
作者: Simpkins G.R. ; Peings Y. ; Magnusdottir G.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2016
卷: 29, 期: 18 起始页码: 6425
结束页码: 6444
语种: 英语
Scopus关键词: Atmospheric temperature
; Atmospheric thermodynamics
; Climate change
; Climatology
; Earth atmosphere
; Mechanical waves
; Surface waters
; Tropics
; Atmosphere-ocean interactions
; Climate variability
; Teleconnections
; Tropical variability
; Variability
; Oceanography
英文摘要: Several recent studies have connected Antarctic climate variability to tropical Atlantic sea surface temperatures (SST), proposing a Rossby wave response from the Atlantic as the primary dynamical mechanism. In this investigation, reanalysis data and atmospheric general circulation model experiments are used to further diagnose these dynamical links. Focus is placed on the possible mediating role of Pacific processes, motivated by the similar spatial characteristics of Southern Hemisphere (SH) teleconnections associated with tropical Atlantic and Pacific SST variability. During austral winter (JJA), both reanalyses and model simulations reveal that Atlantic teleconnections represent a two-mechanism process, whereby increased tropical Atlantic SST promotes two conditions: 1) an intensification of the local Atlantic Hadley circulation (HC), driven by enhanced interaction between SST anomalies and the ITCZ, that increases convergence at the descending branch, establishing anomalous vorticity forcing from which a Rossby wave emanates, expressed as a pattern of alternating positive and negative geopotential height anomalies across the SH extratropics (the so-called HC-driven components); and 2) perturbations to the zonal Walker circulation (WC), driven primarily by an SST-induced amplification, that creates a pattern of anomalous upper-level convergence across the central/western Pacific, from which an ENSO-like Rossby wave train can be triggered (the so-called WC-driven components). While the former are found to dominate, the WC-driven components play a subsidiary yet important role. Indeed, it is the superposition of these two separate but interrelated mechanisms that gives the overall observed response. By demonstrating an additional Pacific-related component to Atlantic teleconnections, this study highlights the need to consider Atlantic-Pacific interactions when diagnosing tropical-related climate variability in the SH extratropics. © 2016 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/50017
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Earth System Science, University of California - Irvine, Irvine, CA, United States
Recommended Citation:
Simpkins G.R.,Peings Y.,Magnusdottir G.. Pacific influences on tropical Atlantic teleconnections to the southern hemisphere high latitudes[J]. Journal of Climate,2016-01-01,29(18)