DOI: 10.1016/j.gloplacha.2013.08.013
论文题名: Millennial-scale versus long-term dynamics in the surface and subsurface of the western North Atlantic Subtropical Gyre during Marine Isotope Stage 5
作者: Bahr A. ; Nürnberg D. ; Karas C. ; Grützner J.
刊名: Global and Planetary Change
ISSN: 0921-8187
出版年: 2013
卷: 111 起始页码: 77
结束页码: 87
语种: 英语
英文关键词: G. ruber
; G. truncatulinoides
; MIS 5
; ODP Site 1058
; Subtropical Gyre
Scopus关键词: Atlantic meridional overturning circulations
; G. ruber
; G. truncatulinoides
; North Atlantic subtropical gyres
; ODP Site 1058
; Overturning circulation
; Subtropical Gyre
; Thermocline temperature
; Atmospheric temperature
; Isotopes
; Oceanography
; Saline water
; Stream flow
; Surface properties
; Tropics
; air-sea interaction
; deglaciation
; Ekman layer
; evaporation
; geoaccumulation
; global warming
; gyre
; hydrography
; latitude
; long-term change
; marine isotope stage
; precipitation (climatology)
; proxy climate record
; temperature effect
; Atlantic Ocean
; Atlantic Ocean (North)
英文摘要: Subtropical Gyres are an important constituent of the ocean-atmosphere system due to their capacity to store vast amounts of warm and saline waters. Here we decipher the sensitivity of the (sub)surface North Atlantic Subtropical Gyre with respect to orbital and millennial scale climate variability between ~. 140 and 70. ka, Marine Isotope Stage (MIS) 5. Using (isotope) geochemical proxy data from surface and thermocline dwelling foraminifers from Blake Ridge off the west coast of North America (ODP Site 1058) we show that the oceanographic development at subsurface (thermocline) level is substantially different from the surface ocean.Most notably, surface temperatures and salinities peak during the penultimate deglaciation (Termination II) and early MIS 5e, implying that subtropical surface ocean heat and salt accumulation might have resulted from a sluggish northward heat transport. In contrast, maximum thermocline temperatures are reached during late MIS 5e when surface temperatures are already declining. We argue that the subsurface warming originated from intensified Ekman downwelling in the Subtropical Gyre due to enhanced wind stress.During MIS 5a-d a tight interplay of the subtropical upper ocean hydrography to high latitude millennial-scale cold events can be observed. At Blake Ridge, the most pronounced of these high latitude cold events are related to surface warming and salt accumulation in the (sub)surface. Similar to Termination II, heat accumulated in the Subtropical Gyre probably due to a reduced Atlantic Meridional Overturning Circulation. Additionally, a southward shift and intensification of the subtropical wind belts lead to a decrease of on-site precipitation and enhanced evaporation, coupled to intensified gyre circulation. Subsequently, the northward advection of this warm and saline water likely contributed to the fast resumption of the overturning circulation at the end of these high latitude cold events. © 2013 Elsevier B.V. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884323729&doi=10.1016%2fj.gloplacha.2013.08.013&partnerID=40&md5=8b68b1bd2f5b100d77c4bdfb251c8dcd
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/11093
Appears in Collections: 全球变化的国际研究计划
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作者单位: University Frankfurt, Institute of Geosciences, Altenhöferallee 1, 60438 Frankfurt am Main, Germany
Recommended Citation:
Bahr A.,Nürnberg D.,Karas C.,et al. Millennial-scale versus long-term dynamics in the surface and subsurface of the western North Atlantic Subtropical Gyre during Marine Isotope Stage 5[J]. Global and Planetary Change,2013-01-01,111.