DOI: 10.1175/JCLI-D-17-0010.1
Scopus记录号: 2-s2.0-85047100127
论文题名: Gulf stream excursions and sectional detachments generate the decadal pulses in the Atlantic multidecadal oscillation
作者: Nigam S. ; Ruiz-Barradas A. ; Chafik L.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2018
卷: 31, 期: 7 起始页码: 2853
结束页码: 2870
语种: 英语
英文关键词: Decadal variability
; Gyres
; North Atlantic ocean
; North Atlantic oscillation
; Sea surface temperature
; Upwelling/downwelling
Scopus关键词: Atmospheric pressure
; Ocean currents
; Decadal variability
; Gyres
; North Atlantic Ocean
; North Atlantic oscillations
; Sea surface temperature (SST)
; Upwelling/downwelling
; Surface waters
英文摘要: Decadal pulses within the lower-frequency Atlantic multidecadal oscillation (AMO) are a prominent but underappreciated AMO feature, representing decadal variability of the subpolar gyre (e.g., the Great Salinity Anomaly of the 1970s) and wielding notable influence on the hydroclimate of the African and American continents. Here clues are sought into their origin in the spatiotemporal development of the Gulf Stream's (GS) meridional excursions and sectional detachments apparent in the 1954-2012 record of ocean surface and subsurface salinity and temperature observations. The GS excursions are tracked via meridional displacement of the 15°C isotherm at 200-m depth-the GS index-whereas the AMO's decadal pulses are targeted through the AMO tendency, which implicitly highlights the shorter time scales of the AMO index. The GS's northward shift is shown to be preceded by the positive phase of the low-frequency North Atlantic Oscillation (LF-NAO) and followed by a positive AMO tendency by 1.25 and 2.5 years, respectively. The temporal phasing is such that the GS's northward shift is nearly concurrent with the AMO's cold decadal phase (cold, fresh subpolar gyre). Ocean-atmosphere processes that can initiate phase reversal of the gyre state are discussed, starting with the reversal of the LF-NAO, leading to a mechanistic hypothesis for decadal fluctuations of the subpolar gyre. According to the hypothesis, the fluctuation time scale is set by the self-feedback of the LF-NAO from its influence on SSTs in the seas around Greenland, and by the cross-basin transit of the GS's detached eastern section; the latter is produced by the southward intrusion of subpolar water through the Newfoundland basin, just prior to the GS's northward shift in the western basin. © 2018 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/111578
Appears in Collections: 气候减缓与适应
There are no files associated with this item.
作者单位: Department of Atmospheric and Oceanic Science, University of Maryland, College Park, College Park, MD, United States; Geophysical Institute, University of Bergen, Bjerknes Centre for Climate Research, Bergen, 5020, Norway; Jefferson Science Fellow, The National Academy of Sciences, Engineering and Medicine, Washington, DC, United States
Recommended Citation:
Nigam S.,Ruiz-Barradas A.,Chafik L.. Gulf stream excursions and sectional detachments generate the decadal pulses in the Atlantic multidecadal oscillation[J]. Journal of Climate,2018-01-01,31(7)