scholarly journals Role of air–sea fluxes and ocean surface density in the production of deep waters in the eastern subpolar gyre of the North Atlantic

Ocean Science ◽  
2021 ◽  
Vol 17 (5) ◽  
pp. 1353-1365
Author(s):  
Tillys Petit ◽  
M. Susan Lozier ◽  
Simon A. Josey ◽  
Stuart A. Cunningham
Keyword(s):  
North Atlantic ◽  
Surface Density ◽  
Ocean Surface ◽  
Density Field ◽  
The North ◽  
Iceland Basin ◽  
Deep Waters ◽  
Water Formation ◽  
Dense Water Formation

Abstract. Wintertime convection in the North Atlantic Ocean is a key component of the global climate as it produces dense waters at high latitudes that flow equatorward as part of the Atlantic Meridional Overturning Circulation (AMOC). Recent work has highlighted the dominant role of the Irminger and Iceland basins in the production of North Atlantic Deep Water. Dense water formation in these basins is mainly explained by buoyancy forcing that transforms surface waters to the deep waters of the AMOC lower limb. Air–sea fluxes and the ocean surface density field are both key determinants of the buoyancy-driven transformation. We analyze these contributions to the transformation in order to better understand the connection between atmospheric forcing and the densification of surface water. More precisely, we study the impact of air–sea fluxes and the ocean surface density field on the transformation of subpolar mode water (SPMW) in the Iceland Basin, a water mass that “pre-conditions” dense water formation downstream. Analyses using 40 years of observations (1980–2019) reveal that the variance in SPMW transformation is mainly influenced by the variance in density at the ocean surface. This surface density is set by a combination of advection, wind-driven upwelling and surface fluxes. Our study shows that the latter explains ∼ 30 % of the variance in outcrop area as expressed by the surface area between the outcropped SPMW isopycnals. The key role of the surface density in SPMW transformation partly explains the unusually large SPMW transformation in winter 2014–2015 over the Iceland Basin.

scholarly journals Role of air-sea fluxes and ocean surface density on the production of deep waters in the eastern subpolar gyre of the North Atlantic

2021 ◽  
Author(s):  
Tillys Petit ◽  
M. Susan Lozier ◽  
Simon A. Josey ◽  
Stuart A. Cunningham
Keyword(s):  
North Atlantic ◽  
Surface Density ◽  
Ocean Surface ◽  
Density Field ◽  
The North ◽  
Iceland Basin ◽  
Deep Waters ◽  
Water Formation ◽  
Dense Water Formation

Abstract. Wintertime convection in the North Atlantic Ocean is a key component of the global climate as it produces dense waters at high latitudes that flow equatorward as part of the Atlantic Meridional Overturning Circulation (AMOC). Recent work has highlighted the dominant role of the Irminger and Iceland basins in the production of North Atlantic Deep Water. Dense water formation in these basins is mainly explained by buoyancy forcing that transforms surface waters to the deep waters of the AMOC lower limb. Air-sea fluxes and the ocean surface density field are both key determinants of the buoyancy-driven transformation. We analyze these contributions to the transformation in order to better understand the connection between atmospheric forcing and the AMOC. More precisely, we study the impact of air-sea fluxes and the ocean surface density field on the transformation of subpolar mode water (SPMW) in the Iceland Basin, a water mass that “pre-conditions” dense water formation downstream. Analyses using 40 years of observations (1980–2019) reveal that the variance in SPMW transformation is mainly influenced by the variance in density at the ocean surface. This surface density is set by a combination of advection, wind-driven upwelling and surface fluxes, the latter explaining ~30 % of the variance in outcrop area as expressed by the surface area between the outcropped SPMW isopycnals. The key role of the surface density on SPMW transformation partly explains the unusually large SPMW transformation in winter 2014–2015 over the Iceland Basin.

Role of the density structure and air-sea fluxes on subpolar transformation

2021 ◽  
Author(s):  
Tillys Petit ◽  
M. Susan Lozier ◽  
Simon A. Josey ◽  
Stuart A. Cunningham
Keyword(s):  
North Atlantic ◽  
Surface Density ◽  
Density Structure ◽  
Dense Water ◽  
The North ◽  
Iceland Basin ◽  
Deep Waters ◽  
Water Formation ◽  
Dense Water Formation

<p>Convection in the North Atlantic Ocean is a key component of the global overturning circulation (MOC) as it produces dense water at high latitudes. Recent work has highlighted the dominant role of the Irminger and Iceland basins in the production of the North Atlantic deep waters. Dense water formation in these basins is mainly explained by buoyancy forcing that transforms surface waters to the deep waters of the MOC lower limb. Air-sea fluxes and the surface density field are both key determinants of the buoyancy-driven transformation. To better understand the connection between atmospheric forcing and the Atlantic overturning circulation, we analyze the contributions of the air-sea fluxes and of the density structure to the transformation of surface water over the eastern subpolar gyre. More precisely, we consider the densification of subpolar mode water (SPMW) in the Iceland Basin that ‘pre-conditions’ the dense water formation downstream. Analyses using 40 years of observations (1980–2019) reveal that variability in transformation is only weakly sensitive to changes in the heat and freshwater fluxes. Instead, changes in SPMW transformation are largely driven by the variance in the surface density structure, as expressed by the outcropping area for those isopycnals that define SPMW.This large influence of the surface density on the SPMW transformation partly explains the unusually large SPMW transformation in winter 2014–15 over the Iceland Basin.  </p>

Dense water formation on the Icelandic shelf and its contribution to the North Icelandic Jet

2021 ◽  
Author(s):  
Yarisbel Garcia‐Quintana ◽  
Nathan Grivault ◽  
Xianmin Hu ◽  
Paul G. Myers
Keyword(s):  
Dense Water ◽  
The North ◽  
Water Formation ◽  
Dense Water Formation

scholarly journals THE (IR)RELEVANCE OF BIBLICAL SCHOLARSHIP? A CHALLENGE, AND AN OPPORTUNITY

Scriptura ◽  
2021 ◽  
Vol 120 (1) ◽  
Author(s):  
Benjamin D. Giffone
Keyword(s):  
North Atlantic ◽  
Qualitative Difference ◽  
Modern World ◽  
The Bible ◽  
Biblical Scholarship ◽  
The North ◽  
Scholarly Discourse ◽  
Biblical Education ◽  
Bible Reading

Has biblical scholarship become irrelevant to modern secular societies? Are the threats to the viability of biblical scholarship of the same nature as the threats to other areas of the humanities (history, philosophy, literature), or is there a qualitative difference? What about the role of technology in biblical research and biblical education? What is the future of the institutions of biblical scholarship such as universities, seminaries, journals, and academic presses? What is the role of biblical scholars in secular and post-secular societies, as contrasted with scholars in/from emerging communities? This essay argues that the problem of “validation” lies at the heart of biblical scholarship’s irrelevancy within the broader secularity of modern world and that this problem is even more evident in the scholarly discourse coming from regions like Eastern Europe and South Africa. However, the loss of authority of biblical scholarship more generally represents an opportunity for these communities. Rather than becoming enamoured of validation from the North Atlantic world, Bible-reading communities must cultivate their own forms of validation based in their unique histories with the Bible, and the affinities between their own histories/cultures and the cultures that produced the Old and New Testament texts.

scholarly journals The Role of Nuclear Weapons in NATO’s Early Cold War Strategies (1949–1957)

2015 ◽  
Vol 14 (1) ◽  
pp. 107-120
Author(s):  
Petra Kiss
Keyword(s):  
Cold War ◽  
International Relations ◽  
North Atlantic ◽  
Nuclear Weapons ◽  
The United States ◽  
Strategic Thinking ◽  
Atomic Weapons ◽  
The North ◽  
Significant Factors

Since August 1945 atomic weapons have become significant factors in international relations, every state with great ambitions has aspired to get atomic secrets. The primary goal of the North Atlantic Treaty Organization (NATO) created in 1949 was – possessing the United States’, a nuclear power’s, security guarantee – to deter the Soviet agression. The first strategic documents of the Alliance were written with this very purpose. However, in the 1950s there was a shift in the allied nations’ policies, which influenced NATO’s strategic thinking as well, so in 1957 a real different strategic concept was adopted. Gaining technological superiority became the most important goal, which led to development and intense production of nuclear weapons. This article examines the emerging role of nuclear weapons and the changing strategy of the Alliance between 1949 and 1957.

scholarly journals LONG-TERM VARIABILITY OF CURRENTS IN THE SUBARCTIC FRONT OF THE ATLANTIC OCEAN

2019 ◽  
Vol 47 (2) ◽  
pp. 246-265
Author(s):  
A. K. Ambrosimov ◽  
N. A. Diansky ◽  
A. A. Kluvitkin ◽  
V. A. Melnikov
Keyword(s):  
North Atlantic ◽  
Ocean Surface ◽  
North Atlantic Current ◽  
Reykjanes Ridge ◽  
The North ◽  
Subarctic Front ◽  
Average Water ◽  
The North Atlantic ◽  
Atlantic Current

Based on time series of near-bottom current velocities and temperatures obtained in the period June, 2016 to July, 2017, at three points in the Atlantic Subarctic Front, along with the use of multi-year (since 1993 up to now) satellite ocean surface sounding data, multi-scale fluctuations of ocean surface and near-bottom flows over the western and eastern flanks of the Reykjanes ridge, as well as near Hatton Rise, on the Rokoll plateau, are studied. Hydrological profiles were carried out from the ocean surface to the bottom with readings every 10 m, when setting and retrieving the buoy stations. Using data from the Bank of hydrological stations (WOD13), SST satellite arrays (Pathfinder), long-term sea level and geostrophic velocities time series (AVISO), and bottom topography (model ETOPO-1), features of longterm cyclical fluctuations of SST, sea level, geostrophic currents on the ocean surface were defined in the sub-polar North Atlantic. It is shown that, in accordance with the large-scale thermohaline structure of the Subarctic front, two branches of the North Atlantic Current are detected on the ocean surface.One is directed from the Hatton towards the Icelandic-Faroese Rise, and the other – alomg the western flank of the Reykjanes Ridge toward Iceland. For the first branch, which is the main continuation of the North Atlantic Current, the average (for 25 years) water drift at a speed of 9.1±0.1 cm/s is determined to the northeast. The second branch, which forms the eastern part of the Subarctic cyclonic gyre, has the average water drift at a speed of 4.0±0.1 cm/s is directed north-northeast, along the western flank of the Reykjanes Ridge. In the intermediate waters of the frontal zone, an average water flow is observed at a speed of 2.7±0.1 cm/s to the north-northeast, along the eastern slope of the Reykjanes ridge.Due to the multy-scale components of the total variability, the average kinetic energy densities(KED) of total currents (109, 45, 97, (±3) erg/cm3, at station points from east to west) are much greater than the mean drift KED. The near-bottom flows on the Reykjanes ridge flanks are opposite to the direction of the North Atlantic Current. Outside the Subarctic gyre, the direction of average transport is maintained from the ocean surface to the bottom. The average (per year) KED of near-bottom currents are 31, 143, 27 (±3 erg/cm3), for three stations from east to west, respectively. In the intermediate waters of the frontal zone, above the eastern slope of the Reykjanes Ridge, there is a powerful reverse (relative to the North Atlantic Current) near-bottom water flow to the south-west, with a high average speed of ~ 15 cm/s. The KED of the currents during the year varies widely from zero to ~ 600 erg/cm3. The overall variability is due to cyclical variations and intermittency (“flashes”) of currents. Perennial cycles, seasonal variations, synoptic fluctuations with periods in the range of 30–300 days, as well as inertial oscillations and semi-diurnal tidal waves are distinguished. The intermittency of oscillations is partly due to changes in low-frequency flows, which can lead to a dopler frequency shift in the cyclic components of the spectrum. The amplitude of temperature fluctuations in the bottom layer for the year was (0.07–0.10) ± 0.01°C by the standard deviation. The seasonal changes of the bottom temperature are not detected. However, a linear trend with a warming of ~ (0.10–0.15) ± 0.01°С per year is noticeable.

scholarly journals Military Security in Central and Eastern Europe – from overarching principles to current NATO perspectives

2019 ◽  
Vol 193 (3) ◽  
pp. 547-557
Author(s):  
Sławomir Wojciechowski
Keyword(s):  
Soviet Union ◽  
North Atlantic ◽  
Central And Eastern Europe ◽  
The North ◽  
The Soviet Union ◽  
Collective Defense ◽  
Military Security ◽  
The Cold War ◽  
Adaptation Processes

This year, NATO is celebrating its 70th anniversary and the signing of the North Atlantic Treaty. The Alliance was founded in the early days of the Cold War, but found itself in a new geopolitical situation after the col-lapse of the Soviet Union and the end of the bipolar world. The organi-zation has been transforming ever since and over time this transfor-mation has included both expansion and adaptation to new circum-stances. With the return of Russian neo-imperial ambitions in the re-cent years, NATO has been given new impetus. Emerging threats and challenges, which are mainly of a military nature, have been addressed by NATO through further recent adaptation processes which were based on the return to the core role of the Alliance, namely collective defense and deterrence. This, in turn, has created a boost of NATO ac-tivity on the ground, which means that improvement with regard to interoperability and integration is now in high demand.

scholarly journals Checklist of the salps (Tunicata, Thaliacea) from the Western Caribbean Sea with a key for their identification and comments on other North Atlantic salps

Zootaxa ◽  
2012 ◽  
Vol 3210 (1) ◽  
pp. 50 ◽  
Author(s):  
CLARA MARÍA HEREU ◽  
EDUARDO SUÁREZ-MORALES
Keyword(s):  
North Atlantic ◽  
Caribbean Sea ◽  
Depth Range ◽  
Tropical Atlantic ◽  
The North ◽  
New Information ◽  
Plankton Biomass ◽  
Western Caribbean ◽  
The Caribbean

In waters of the Northwestern Atlantic pelagic tunicates may contribute significantly to the plankton biomass; however, theregional information on the salp fauna is scarce and limited to restricted sectors. In the Caribbean Sea (CS) and the Gulf ofMexico (GOM) the composition of the salpid fauna is still poorly known and this group remains among the less studiedzooplankton taxa in the Northwestern Tropical Atlantic. A revised checklist of the salp species recorded in the North At-lantic (NA, 0–40° N) is provided herein, including new information from the Western Caribbean. Zooplankton sampleswere collected during two cruises (March 2006, January 2007) within a depth range of 0–941 m. A total of 14 species wererecorded in our samples, including new records for the CS and GOM area (Cyclosalpa bakeri Ritter 1905), for the CS (Cy-closalpa affinis (Chamisso, 1819)), and for the Western Caribbean (Salpa maxima Forskål, 1774). The number of speciesof salps known from the CS and GOM rose to 18. A key for the identification of the species recorded in the region is provided. Studies on the ecological role of salps in several sectors of the NA are scarce and deserve further attention.

Sign in / Sign up

Export Citation Format

Share Document