The role of the deep ocean in North Atlantic climate change between 70 and 130 kyr ago

Nature ◽  
1994 ◽  
Vol 371 (6495) ◽  
pp. 323-326 ◽  
Author(s):  
L. D. Keigwin ◽  
W. B. Curry ◽  
S. J. Lehman ◽  
S. Johnsen
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Deep Ocean ◽  
North Atlantic Climate

scholarly journals The role of continental shelves in nitrogen and carbon cycling

2010 ◽  
Vol 7 (1) ◽  
pp. 177-205
Author(s):  
K. Fennel
Keyword(s):  
Continental Shelf ◽  
North Atlantic ◽  
Deep Ocean ◽  
Open Ocean ◽  
Biogeochemical Models ◽  
Inorganic Matter ◽  
Continental Shelves ◽  
Shelf Region ◽  
Transformation Processes

Abstract. Continental shelves play a key role in the cycling of nitrogen and carbon. Here the physical transport and biogeochemical transformation processes affecting the fluxes into and out of continental shelf systems are reviewed, and their role in the global cycling of both elements is discussed. Uncertainties in observation-based estimates of nitrogen and carbon fluxes mostly result from uncertainties in the shelf-open ocean exchange of organic and inorganic matter, which is hard to quantify based on observations alone, but can be inferred from biogeochemical models. Model-based nitrogen and carbon budgets are presented for the Northwestern North Atlantic continental shelf. Results indicate that shelves are an important sink for fixed nitrogen and a source of alkalinity, but are not much more efficient in exporting organic carbon to the deep ocean than the adjacent open ocean for the shelf region considered.

scholarly journals Evolving southwest African response to abrupt deglacial North Atlantic climate change events

2015 ◽  
Vol 121 ◽  
pp. 132-136 ◽  
Author(s):  
Brian M. Chase ◽  
Arnoud Boom ◽  
Andrew S. Carr ◽  
Matthieu Carré ◽  
Manuel Chevalier ◽  
...  
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Change Events ◽  
North Atlantic Climate

scholarly journals The role of continental shelves in nitrogen and carbon cycling: Northwestern North Atlantic case study

Ocean Science ◽  
2010 ◽  
Vol 6 (2) ◽  
pp. 539-548 ◽  
Author(s):  
K. Fennel
Keyword(s):  
Continental Shelf ◽  
North Atlantic ◽  
Deep Ocean ◽  
Open Ocean ◽  
Biogeochemical Models ◽  
Inorganic Matter ◽  
Continental Shelves ◽  
Shelf Region

Abstract. Continental shelves play a key role in the cycling of nitrogen and carbon. Here the physical transport and biogeochemical transformation processes affecting the fluxes into and out of continental shelf systems are reviewed, and their role in the global cycling of both elements is discussed. Uncertainties in the magnitude of organic and inorganic matter exchange between shelves and the open ocean is a major source of uncertainty in observation-based estimates of nitrogen and carbon fluxes. The shelf-open ocean exchange is hard to quantify based on observations alone, but can be inferred from biogeochemical models. Model-based nitrogen and carbon budgets are presented for the Northwestern North Atlantic continental shelf. Results indicate that shelves are an important sink for fixed nitrogen and a source of alkalinity, but are not much more efficient in exporting organic carbon to the deep ocean than the adjacent open ocean for the shelf region considered.

scholarly journals The role of local sea surface temperature pattern changes in shaping climate change in the North Atlantic sector

2018 ◽  
Vol 52 (1-2) ◽  
pp. 417-438 ◽  
Author(s):  
Ralf Hand ◽  
Noel S. Keenlyside ◽  
Nour-Eddine Omrani ◽  
Jürgen Bader ◽  
Richard J. Greatbatch
Keyword(s):  
Climate Change ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
Sea Surface ◽  
Temperature Pattern ◽  
Atlantic Sector ◽  
The North ◽  
The North Atlantic

Twentieth century North Atlantic climate change. Part II: Understanding the effect of Indian Ocean warming

2004 ◽  
Vol 23 (3-4) ◽  
pp. 391-405 ◽  
Author(s):  
M. P. Hoerling ◽  
J. W. Hurrell ◽  
T. Xu ◽  
G. T. Bates ◽  
A. S. Phillips
Keyword(s):  
Climate Change ◽  
Twentieth Century ◽  
Indian Ocean ◽  
North Atlantic ◽  
Ocean Warming ◽  
Indian Ocean Warming ◽  
North Atlantic Climate

Variable response of North Atlantic deep-sea benthic ecosystems to industrial-era climate change

2021 ◽  
Author(s):  
Charlotte O'Brien ◽  
Peter Spooner ◽  
David Thornalley ◽  
Jack Wharton ◽  
Eirini Papachristopoulou ◽  
...  
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Deep Sea ◽  
Sediment Cores ◽  
Regional Scale ◽  
Deep Ocean ◽  
Variable Response ◽  
The Holocene ◽  
Surface Ocean ◽  
Benthic Ecosystems

<p><strong>Traditionally, deep-sea ecosystems have been considered to be insulated from the effects of modern climate change. Yet, with the recognition of the importance of food supply from the surface ocean and deep-sea currents to sustaining these systems, the potential for rapid response of benthic systems to climate change is gaining increasing attention. North Atlantic benthic responses to past climate change have been well-documented using marine sediment cores on glacial-interglacial timescales, and ocean sediments have also begun to reveal that planktic species assemblages are already being influenced by global warming. However, very few ecological time-series exist for the deep ocean covering the Holocene-through-industrial era. Here, we use benthic and planktic foraminifera found in Northeast Atlantic (EN539-MC16-A/B and RAPID-17-5P), Northwest Atlantic (KNR158-4-10MC and KNR158-4-9GGC) and Labrador Sea (RAPID-35-25B and RAPID-35-14P) sediments to show that, in locations beneath areas of major North Atlantic surface water change, benthic ecosystems have also changed significantly over the industrial era relative to the Holocene. We find that the response of the benthos is dependent on changes in the surface ocean near to the study sites. Our work highlights the spatial heterogeneity of these benthic ecosystem changes and therefore the need for local-regional scale modelling and observations to better understand responses to deep-sea circulation changes and modern surface climate change. </strong></p>

scholarly journals A coarse resolution North Atlantic ocean circulation model: an intercomparison study with a paleoceanographic example

1996 ◽  
Vol 14 (2) ◽  
pp. 246-257 ◽  
Author(s):  
Dan Seidov ◽  
Ralf Prien
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
Numerical Models ◽  
Bottom Topography ◽  
Circulation Model ◽  
Deep Ocean ◽  
Return Flow ◽  
Freshwater Flux ◽  
Surface Boundary

Abstract. Paleoreconstructions suggest that during the Last Glacial Maximum (LGM) the North Atlantic circulation was noticeably different from its present state. However, the glacial salt conveyor belt is believed to be similar to the present-day's conveyor, albeit weaker and shallower because of an increased freshwater flux in high-latitudes. We present here the investigation of the conveyor operation based on ocean circulation modelling using two numerical models in parallel. The GFDL primitive equation model and a planetary geostrophic model are employed to address the problem of the paleocirculation modelling in cases of uncertain and sparse data comprising the glacial surface boundary conditions. The role of different simplifications that may be used in the ocean climate studies, including the role of grid resolution, bottom topography, coast-line, etc., versus glacial-interglacial changes of the ocean surface climatology is considered. The LGM reverse conveyor gyre appeared to be the most noticeable feature of the glacial-to-interglacial alteration of the ocean circulation. The reversed upper-ocean conveyor, weaker and subducting 'normal' conveyor in the intermediate depths, and the change of the deep-ocean return flow route are robust signatures of the glacial North Atlantic climate. The results are found to be 'model-independent' and fairly insensitive to all factors other than the onset of the glacial surface conditions.

Holocene periodicity in North Atlantic climate and deep-ocean flow south of Iceland

Nature ◽  
10.1038/17362 ◽  
1999 ◽  
Vol 397 (6719) ◽  
pp. 515-517 ◽  
Author(s):  
Giancarlo G. Bianchi ◽  
I. Nicholas McCave
Keyword(s):  
North Atlantic ◽  
Deep Ocean ◽  
North Atlantic Climate

Observational analysis of Mediterranean decadal hydroclimate variability: role of Atlantic-Mediterranean sea surface temperatures

2020 ◽  
Author(s):  
Roberto Suarez-Moreno ◽  
Richard Seager ◽  
Yochanan Kushnir
Keyword(s):  
Climate Change ◽  
North Atlantic ◽  
Mediterranean Region ◽  
Sea Surface ◽  
Wet Season ◽  
The North ◽  
Hydroclimate Variability ◽  
The North Atlantic ◽  
The Mediterranean

<p>The Mediterranean region is a semi-arid climate zone, subject to droughts, where water resources are scarce and observational data and climate models suggest a tendency towards greater aridification. Moreover, the Mediterranean region is an area of social and political instability and, in the Middle East, open warfare, which might be further stressed by climate change. The North Atlantic Oscillation (NAO) is the dominant mode of winter climate variability in the North Atlantic sector, playing the leading role in driving Mediterranean hydroclimate variability from seasonal to multidecadal timescales, whereas the influence of sea surface temperatures (SSTs) remains unclear. Nevertheless, the mechanism underlying the NAO is still under debate, and the possibility for coupled ocean-atmosphere decadal interactions, for which several mechanisms have been proposed, would support the role of SST. Based on observations and reanalysis, we conduct a statistical-observational analysis to explore the decadal drivers of Mediterranean hydroclimate variability for the winter half-year (October-to-March) wet season. Our results put forward the uneven intraseasonal influence of the decadal NAO, being the leading driver during the winter peak season (December-to-March), while decadal Atlantic-Mediterranean SST variability exhibit a consistent link for the first months of the wet season (October-to-January). These results emphasize the need to further explore the ocean-atmosphere feedback mechanisms and their possible modulations under climate change. Understanding these mechanisms is essential to improve predictability of hydroclimate in the Mediterranean region, leading to adaptation strategies that mitigate the effect of climate change on the vulnerable population.</p>

scholarly journals The role of the North Atlantic overturning and deep-ocean for multi-decadal global-mean-temperature variability

2013 ◽  
Vol 4 (2) ◽  
pp. 967-1003 ◽  
Author(s):  
C. F. Schleussner ◽  
J. Runge ◽  
J. Lehmann ◽  
A. Levermann
Keyword(s):  
Sea Ice ◽  
North Atlantic ◽  
Heat Content ◽  
Deep Ocean ◽  
Meridional Overturning Circulation ◽  
Cmip5 Models ◽  
Global Mean Temperature ◽  
Mean Temperature ◽  
Global Mean

Abstract. Earth's climate exhibits internal modes of variability on various time scales. Here we investigate multi-decadal variability of the Atlantic meridional overturning circulation (AMOC) in the control runs of an ensemble of CMIP5 models. By decomposing global-mean-temperature (GMT) variance into contributions of the AMOC and Northern Hemisphere sea-ice extent using a graph-theoretical statistical approach, we find the AMOC to contribute 8% to GMT variability in the ensemble mean. Our results highlight the importance of AMOC sea-ice feedbacks that explain 5% of the GMT variance, while the contribution solely related to the AMOC is found to be about 3%. As a consequence of multi-decadal AMOC variability, we report substantial variations in North Atlantic deep-ocean heat content with trends of up to 0.7 × 1022 J decade−1 that are of the order of observed changes over the last decade and consistent with the reduced GMT warming trend over this period. Although these temperature anomalies are largely density-compensated by salinity changes, we find a robust negative correlation between the AMOC and North Atlantic deep-ocean density with density lagging the AMOC by 5 to 11 yr in most models. While this would in principle allow for a self-sustained oscillatory behavior of the coupled AMOC–deep-ocean system, our results are inconclusive about the role of this feedback in the model ensemble.

Sign in / Sign up

Export Citation Format

Share Document