Impact of flow through the Canadian Archipelago and Bering Strait on the North Atlantic and Arctic circulation: An ocean modelling study

2002 ◽  
Vol 128 (585) ◽  
pp. 2187-2203 ◽  
Author(s):  
Martin R. Wadley ◽  
Grant R. Bigg
Keyword(s):  
North Atlantic ◽  
Bering Strait ◽  
Ocean Modelling ◽  
The North ◽  
Flow Through ◽  
The North Atlantic ◽  
Modelling Study

scholarly journals Seasonal Barotropic Modulation of the Deep-Water Overflow through the Faroe Bank Channel

2006 ◽  
Vol 36 (12) ◽  
pp. 2328-2339 ◽  
Author(s):  
Iréne Lake ◽  
Peter Lundberg
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
Satellite Altimetry ◽  
North Atlantic Ocean ◽  
Norwegian Sea ◽  
The North ◽  
Flow Through ◽  
The North Atlantic ◽  
Water Overflow

Abstract As a joint Nordic project, an upward-looking ADCP has been maintained at the sill of the Faroe Bank Channel from 1995 onward. Records from a period in 1998 with three current meters deployed across the channel were used to demonstrate that the Faroe Bank Channel deep-water transport from the Norwegian Sea into the North Atlantic Ocean proper can be reasonably well estimated from one centrally located ADCP. The long-term average of this transport over the period 1995–2001 was found to be 2.1 Sv (Sv ≡ 106 m−3 s−1). The transport record demonstrates a pronounced seasonality. Satellite altimetry shows that this is caused by the northbound Atlantic surface water inflow giving rise to a barotropic modulation of the deep-water flow through the Faroe–Shetland Channel and the southern reaches of the Norwegian Sea.

scholarly journals On the peopling of the Americas: molecular evidence for the Paleoamerican and the Solutrean models

2017 ◽  
Author(s):  
Dejian Yuan ◽  
Shi Huang
Keyword(s):  
North Atlantic ◽  
North Atlantic Ocean ◽  
Molecular Evidence ◽  
Bering Strait ◽  
East Asians ◽  
The North ◽  
Pack Ice ◽  
Peopling Of The Americas ◽  
Close Relationship ◽  
The North Atlantic

AbstractMorphological and archaeological studies suggest that the Americas were first occupied by non-Mongoloids with Australo-Melanesian traits (the Paleoamerican model), which was subsequently followed by Southwest Europeans coming in along the pack ice of the North Atlantic Ocean (the Solutrean model) and by East Asians and Siberians arriving by way of the Bering Strait. Past DNA studies, however, have produced different accounts. With a better understanding of genetic diversity, we have now reinterpreted public DNA data. Consistent with our recent finding of a close relationship between South Pacific populations and Denisovans or Neanderthals who were archaic Africans with Eurasian admixtures, the ∼9500 year old Kennewick Man skeleton with Australo-Melanesian affinity from North America was about equally related to Europeans and Africans, least related to East Asians among present-day people, and most related to the ∼42000 year old Neanderthal Mezmaiskaya-2 from Adygea Russia among ancient Eurasian DNAs. The ∼12700 year old Anzick-1 of the Clovis culture was most related to the ∼18720 year old El Miron of the Magdalenian culture in Spain among ancient DNAs. Amerindian mtDNA haplotypes, unlike their Eurasian sister haplotypes, share informative SNPs with Australo-Melanesians, Africans, or Neanderthals. These results suggest a unifying account of informative findings on the settlement of the Americas.

New evidence from the western Canadian Arctic Archipelago for the resubmergence of Bering Strait

2008 ◽  
Vol 70 (1) ◽  
pp. 60-67 ◽  
Author(s):  
John H. England ◽  
Mark F.A. Furze
Keyword(s):  
Arctic Ocean ◽  
North Atlantic ◽  
Canadian Arctic ◽  
Laptev Sea ◽  
Canadian Arctic Archipelago ◽  
Bering Strait ◽  
The North ◽  
Banks Island ◽  
The North Atlantic ◽  
The Laptev Sea

AbstractWidespread molluscan samples were collected from raised marine sediments to date the last retreat of the NW Laurentide Ice Sheet from the western Canadian Arctic Archipelago. At the head of Mercy Bay, northern Banks Island, deglacial mud at the modern coast contains Hiatella arctica and Portlandia arctica bivalves, as well as Cyrtodaria kurriana, previously unreported for this area. Multiple H. arctica and C. kurriana valves from this site yield a mean age of 11.5 14C ka BP (with 740 yr marine reservoir correction). The occurrence of C. kurriana, a low Arctic taxon, raises questions concerning its origin, because evidence is currently lacking for a molluscan refugium in the Arctic Ocean during the last glacial maximum. Elsewhere, the oldest late glacial age available on C. kurriana comes from the Laptev Sea where it is < 10.3 14C ka BP and attributed to a North Atlantic source. This is 2000 cal yr younger than the Mercy Bay samples reported here, making the Laptev Sea, ~ 3000 km to the west, an unlikely source. An alternate route from the North Atlantic into the Canadian Arctic Archipelago was precluded by coalescent Laurentide, Innuitian and Greenland ice east of Banks Island until ~ 10 14C ka BP. We conclude that the presence of C. kurriana on northern Banks Island records migration from the North Pacific. This requires the resubmergence of Bering Strait by 11.5 14C ka BP, extending previous age determinations on the reconnection of the Pacific and Arctic oceans by up to 1000 yr. This renewed ingress of Pacific water likely played an important role in re-establishing Arctic Ocean surface currents, including the evacuation of thick multi-year sea ice into the North Atlantic prior to the Younger Dryas geochron.

scholarly journals Response of Thermohaline Circulation to Freshwater Forcing under Present-Day and LGM Conditions

2008 ◽  
Vol 21 (10) ◽  
pp. 2239-2258 ◽  
Author(s):  
Aixue Hu ◽  
Bette L. Otto-Bliesner ◽  
Gerald A. Meehl ◽  
Weiqing Han ◽  
Carrie Morrill ◽  
...  
Keyword(s):  
North Atlantic ◽  
Thermohaline Circulation ◽  
North Atlantic Ocean ◽  
The Arctic ◽  
Bering Strait ◽  
Climate System Model ◽  
The North ◽  
Freshwater Forcing ◽  
Bering Strait Throughflow ◽  
The North Atlantic

Abstract Responses of the thermohaline circulation (THC) to freshwater forcing (hosing) in the subpolar North Atlantic Ocean under present-day and the last glacial maximum (LGM) conditions are investigated using the National Center for Atmospheric Research Community Climate System Model versions 2 and 3. Three sets of simulations are analyzed, with each set including a control run and a freshwater hosing run. The first two sets are under present-day conditions with an open and closed Bering Strait. The third one is under LGM conditions, which has a closed Bering Strait. Results show that the THC nearly collapses in all three hosing runs when the freshwater forcing is turned on. The full recovery of the THC, however, is at least a century earlier in the open Bering Strait run than the closed Bering Strait and LGM runs. This is because the excessive freshwater is diverged almost equally toward north and south from the subpolar North Atlantic when the Bering Strait is open. A significant portion of the freshwater flowing northward into the Arctic exits into the North Pacific via a reversed Bering Strait Throughflow, which accelerates the THC recovery. When the Bering Strait is closed, this Arctic to Pacific transport is absent and freshwater can only be removed through the southern end of the North Atlantic. Together with the surface freshwater excess due to precipitation, evaporation, river runoff, and melting ice in the closed Bering Strait experiments after the hosing, the removal of the excessive freshwater takes longer, and this slows the recovery of the THC. Although the background conditions are quite different between the present-day closed Bering Strait run and the LGM run, the THC responds to the freshwater forcing added in the North Atlantic in a very similar manner.

North Pacific Climate Response to Freshwater Forcing in the Subarctic North Atlantic: Oceanic and Atmospheric Pathways

2009 ◽  
Vol 22 (6) ◽  
pp. 1424-1445 ◽  
Author(s):  
Yuko M. Okumura ◽  
Clara Deser ◽  
Aixue Hu ◽  
Axel Timmermann ◽  
Shang-Ping Xie
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
The Arctic ◽  
Bering Strait ◽  
Aleutian Low ◽  
Freshwater Input ◽  
The North ◽  
The North Atlantic ◽  
The North Pacific ◽  
The Last Glacial

Abstract Sudden changes of the Atlantic meridional overturning circulation (AMOC) are believed to have caused large, abrupt climate changes over many parts of the globe during the last glacial and deglacial period. This study investigates the mechanisms by which a large freshwater input to the subarctic North Atlantic and an attendant rapid weakening of the AMOC influence North Pacific climate by analyzing four different ocean–atmosphere coupled general circulation models (GCMs) under present-day or preindustrial boundary conditions. When the coupled GCMs are forced with a 1-Sv (Sv ≡ 106 m3 s−1) freshwater flux anomaly in the subarctic North Atlantic, the AMOC nearly shuts down and the North Atlantic cools significantly. The South Atlantic warms slightly, shifting the Atlantic intertropical convergence zone southward. In addition to this Atlantic ocean–atmosphere response, all of the models exhibit cooling of the North Pacific, especially along the oceanic frontal zone, consistent with paleoclimate reconstructions. The models also show deepening of the wintertime Aleutian low. Detailed analysis of one coupled GCM identifies both oceanic and atmospheric pathways from the Atlantic to the North Pacific. The oceanic teleconnection contributes a large part of the North Pacific cooling: the freshwater input to the North Atlantic raises sea level in the Arctic Ocean and reverses the Bering Strait throughflow, transporting colder, fresher water from the Arctic Ocean into the North Pacific. When the Bering Strait is closed, the cooling is greatly reduced, while the Aleutian low response is enhanced. Tropical SST anomalies in both the Atlantic and Pacific are found to be important for the equivalent barotropic response of the Aleutian low during boreal winter. The atmospheric bridge from the tropical North Atlantic is particularly important and quite sensitive to the mean state, which is poorly simulated in many coupled GCMs. The enhanced Aleutian low, in turn, cools the North Pacific by increasing surface heat fluxes and southward Ekman transport. The closure of the Bering Strait during the last glacial period suggests that the atmospheric bridge from the tropics and air–sea interaction in the North Pacific played a crucial role in the AMOC–North Pacific teleconnection.

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