scholarly journals On the spatial coherence of the Atlantic Water inflow across the Nordic Seas

2017 ◽  
Vol 122 (5) ◽  
pp. 4346-4363 ◽  
Author(s):  
Christophe Herbaut ◽  
Marie-Noëlle Houssais ◽  
Sally Close ◽  
Anne-Cécile Blaizot
2021 ◽  
Author(s):  
Sourav Chatterjee ◽  
Roshin P Raj ◽  
Laurent Bertino ◽  
Nuncio Murukesh

<p>Enhanced intrusion of warm and saline Atlantic Water (AW) to the Arctic Ocean (AO) in recent years has drawn wide interest of the scientific community owing to its potential role in ‘Arctic Amplification’. Not only the AW has warmed over the last few decades , but its transfer efficiency have also undergone significant modifications due to changes in atmosphere and ocean dynamics at regional to large scales. The Nordic Seas (NS), in this regard, play a vital role as the major exchange of polar and sub-polar waters takes place in this region. Further, the AW and its significant modification on its way to AO via the Nordic Seas has large scale implications on e.g., deep water formation, air-sea heat fluxes. Previous studies have suggested that a change in the sub-polar gyre dynamics in the North Atlantic controls the AW anomalies that enter the NS and eventually end up in the AO. However, the role of NS dynamics in resulting in the modifications of these AW anomalies are not well studied. Here in this study, we show that the Nordic Seas are not only a passive conduit of AW anomalies but the ocean circulations in the Nordic Seas, particularly the Greenland Sea Gyre (GSG) circulation can significantly change the AW characteristics between the entry and exit point of AW in the NS. Further, it is shown that the change in GSG circulation can modify the AW heat distribution in the Nordic Seas and can potentially influence the sea ice concentration therein. Projected enhanced atmospheric forcing in the NS in a warming Arctic scenario and the warming trend of the AW can amplify the role of NS circulation in AW propagation and its impact on sea ice, freshwater budget and deep water formation.</p>


2020 ◽  
Vol 188 ◽  
pp. 102447 ◽  
Author(s):  
Sebastian Menze ◽  
Randi B. Ingvaldsen ◽  
Anna Nikolopoulos ◽  
Tore Hattermann ◽  
Jon Albretsen ◽  
...  

2020 ◽  
Vol 8 ◽  
Author(s):  
Nicolas Van Nieuwenhove ◽  
Audrey Limoges ◽  
Niels Nørgaard-Pedersen ◽  
Marit-Solveig Seidenkrantz ◽  
Sofia Ribeiro

2010 ◽  
Vol 29 (9-10) ◽  
pp. 1276-1287 ◽  
Author(s):  
J. Giraudeau ◽  
M. Grelaud ◽  
S. Solignac ◽  
J.T. Andrews ◽  
M. Moros ◽  
...  

2018 ◽  
Author(s):  
Anna Makarewicz ◽  
Piotr Kowalczuk ◽  
Sławomir Sagan ◽  
Mats A. Granskog ◽  
Alexey K. Pavlov ◽  
...  

Abstract. Optical properties of Chromophoric (CDOM) and Fluorescent Dissolved Organic Matter (FDOM) were characterized in the Nordic Seas including the West Spitsbergen Shelf during June–July of 2013, 2014 and 2015. The CDOM absorption coefficient at 350 nm, aCDOM(350) showed significant interannual variation. In 2013, the highest average aCDOM(350) values (aCDOM = 0.30 ± 0.12 m−1) were observed due to the influence of cold and low–saline water from the Sørkapp Current in the southern part of West Spitsbergen Shelf. In 2014, aCDOM(350) values were significantly lower than in 2013 (av. aCDOM(350) = 0.14 ± 0.06 m−1), which was associated with the dominance of warm and saline Atlantic Water (AW) in the region, while in 2015 intermediate CDOM absorption (av. aCDOM(350) = 0.19 ± 0.05 m−1) was observed. In situ measurement of three FDOM components revealed that protein–like FDOM dominated and concentration of marine and terrestrial humic–like DOM were very low and its distribution were generally vertically homogenous in the upper ocean (0–100 m). Fluorescence of terrestrial and marine humic–like FDOM decreased in surface waters (0–15 m) near the sea–ice edge by dilution of oceanic waters by sea–ice melt water. The vertical distribution of protein–like FDOM was characterized by a prominent sub–surface maximum that matched the subsurface chlorophyll a maximum and was observed all across the study area. The highest protein–like FDOM fluorescence was observed in the Norwegian Sea in the core of warm AW. There was a significant relationship between the protein–like fluorescence and chlorophyll a fluorescence (R2 = 0.65, p 


2019 ◽  
Vol 15 (3) ◽  
pp. 1171-1186 ◽  
Author(s):  
Flor Vermassen ◽  
Nanna Andreasen ◽  
David J. Wangner ◽  
Nicolas Thibault ◽  
Marit-Solveig Seidenkrantz ◽  
...  

Abstract. The mass loss from the Greenland Ice Sheet has increased over the past 2 decades. Marine-terminating glaciers contribute significantly to this mass loss due to increased melting and ice discharge. Periods of rapid retreat of these tidewater glaciers have been linked to the concurrent inflow of warm Atlantic-sourced waters. However, little is known about the variability of these Atlantic-derived waters within the fjords, due to a lack of multi-annual in situ measurements. Thus, to better understand the potential role of ocean warming on glacier retreat, reconstructions that characterize the variability of Atlantic water inflow to the fjords are required. Here, we investigate foraminiferal assemblages in a sediment core from Upernavik Fjord, West Greenland, in which the major ice stream Upernavik Isstrøm terminates. We conclude that the foraminiferal assemblage is predominantly controlled by changes in bottom water composition and provide a reconstruction of Atlantic water inflow to Upernavik Fjord, spanning the period 1925–2012. This reconstruction reveals peak Atlantic water influx during the 1930s and again after 2000, a pattern that is comparable to the Atlantic Multidecadal Oscillation (AMO). The comparison of these results to historical observations of front positions of Upernavik Isstrøm reveals that inflow of warm Atlantic-derived waters likely contributed to high retreat rates in the 1930s and after 2000. However, moderate retreat rates of Upernavik Isstrøm also prevailed in the 1960s and 1970s, showing that glacier retreat continued despite a reduced Atlantic water inflow, albeit at a lower rate. Considering the link between bottom water variability and the AMO in Upernavik Fjord, and the fact that a persistent negative phase of the AMO is expected for the next decade, Atlantic water inflow into the fjord may decrease in the coming decade, potentially minimizing or stabilizing the retreat of Upernavik Isstrøm during this time interval.


Ocean Science ◽  
2013 ◽  
Vol 9 (6) ◽  
pp. 957-975 ◽  
Author(s):  
W. Walczowski

Abstract. The structures of the hydrographic fronts separating the Atlantic-origin waters from ambient waters in the northern Nordic Seas are discussed. Flows of the western and eastern branches of the West Spitsbergen Current create the Atlantic domain borders and maintain these fronts. This work is based on previous research and on investigations carried out in the project DAMOCLES (Developing Arctic Modelling and Observational Capabilities for Long-term Environmental Studies). Most of the observational data were collected during the R/V Oceania cruises. The main focus of the paper is the western border of the Atlantic domain – the Arctic Front, alongfrontal and transfrontal transports, and the front instability and variability. The alongfrontal baroclinic jet streams were described as a significant source of the Atlantic Water and heat in the Nordic Seas. The baroclinic instability and advection of baroclinic eddies which occurs due to this instability were found to be the main transfrontal transport processes. Most of the Atlantic Water transported by the western branch recirculates west and southward. The eastern branch of the West Spitsbergen Current provides most of the Atlantic Water entering the Arctic Ocean. Both processes are very important for the Arctic and global thermohaline circulation.


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