scholarly journals A regional ocean circulation model for the mid-Cretaceous North Atlantic Basin: implications for black shale formation

2011 ◽  
Vol 7 (1) ◽  
pp. 277-297 ◽  
Author(s):  
R. P. M. Topper ◽  
J. Trabucho Alexandre ◽  
E. Tuenter ◽  
P. Th. Meijer
Keyword(s):  
Ocean Circulation ◽  
Black Shale ◽  
North Atlantic ◽  
Initial Conditions ◽  
Regional Model ◽  
Black Shales ◽  
Global Ocean ◽  
Atlantic Basin ◽  
North Atlantic Basin ◽  
Shale Formation

Abstract. High concentrations of organic matter accumulated in marine sediments during Oceanic Anoxic Events (OAEs) in the Cretaceous. Model studies examining these events invariably make use of global ocean circulation models. In this study, a regional model for the North Atlantic Basin during OAE2 at the Cenomanian-Turonian boundary has been developed. A first order check of the results has been performed by comparison with the results of a recent global Cenomanian CCSM3 run, from which boundary and initial conditions were obtained. The regional model is able to maintain tracer patterns and to produce velocity patterns similar to the global model. The sensitivity of the basin tracer and circulation patterns to changes in the geometry of the connections with the global ocean is examined with three experiments with different bathymetries near the sponges. Different geometries turn out to have little effect on tracer distribution, but do affect circulation and upwelling patterns. The regional model is also used to test the hypothesis that ocean circulation may have been behind the deposition of black shales during OAEs. Three scenarios are tested which are thought to represent pre-OAE, OAE and post-OAE situations. Model results confirm that Pacific intermediate inflow together with coastal upwelling could have enhanced primary production during OAE2. A low sea level in the pre-OAE scenario could have inhibited large scale black shale formation, as could have the opening of the Equatorial Atlantic Seaway in the post-OAE scenario.

scholarly journals A regional ocean circulation model for the mid-Cretaceous North Atlantic Basin: implications for black shale formation

2010 ◽  
Vol 6 (5) ◽  
pp. 2371-2421 ◽  
Author(s):  
R. P. M. Topper ◽  
J. Trabucho Alexandre ◽  
E. Tuenter ◽  
P. Th. Meijer
Keyword(s):  
Ocean Circulation ◽  
Black Shale ◽  
North Atlantic ◽  
Initial Conditions ◽  
Regional Model ◽  
Black Shales ◽  
Global Ocean ◽  
Atlantic Basin ◽  
North Atlantic Basin ◽  
Shale Formation

Abstract. High concentrations of organic matter accumulated in marine sediments during Oceanic Anoxic Events (OAEs) in the Cretaceous. Model studies examining these events invariably make use of global ocean circulation models. In this study, a regional model for the North Atlantic Basin during OAE2 at the Cenomanian-Turonian boundary is developed. A first order check of the results is performed by comparison with the results of a recent global Cenomanian CCSM3 run from which boundary and initial conditions were obtained. The regional model is able to maintain tracer patterns and to produce velocity patterns similar to the global model. The sensitivity of basin tracer and circulation patterns to changes in the geometry of the connections with the global ocean is examined with three experiments with different bathymetries near the sponges. Different geometries turn out to have little effect on tracer distribution, but do affect circulation and upwelling patterns. The regional model is also used to test the hypothesis that ocean circulation may be behind the deposition of black shales during OAEs. Three scenarios are tested which are thought to represent pre-OAE, OAE and post-OAE situations. Model results confirm that Pacific intermediate inflow together with coastal upwelling can have enhanced primary production during OAE2. A low sea level in the pre-OAE scenario can inhibit large scale black shale formation, as can the opening of the Equatorial Atlantic Seaway in the post-OAE scenario.

The Role of Oscillating Southern Hemisphere Westerly Winds: Global Ocean Circulation

2020 ◽  
Vol 33 (6) ◽  
pp. 2111-2130
Author(s):  
Woo Geun Cheon ◽  
Jong-Seong Kug
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
North Pacific ◽  
Global Ocean ◽  
The North ◽  
Westerly Winds ◽  
The North Atlantic ◽  
Global Ocean Circulation ◽  
The Antarctic ◽  
The North Pacific

AbstractIn the framework of a sea ice–ocean general circulation model coupled to an energy balance atmospheric model, an intensity oscillation of Southern Hemisphere (SH) westerly winds affects the global ocean circulation via not only the buoyancy-driven teleconnection (BDT) mode but also the Ekman-driven teleconnection (EDT) mode. The BDT mode is activated by the SH air–sea ice–ocean interactions such as polynyas and oceanic convection. The ensuing variation in the Antarctic meridional overturning circulation (MOC) that is indicative of the Antarctic Bottom Water (AABW) formation exerts a significant influence on the abyssal circulation of the globe, particularly the Pacific. This controls the bipolar seesaw balance between deep and bottom waters at the equator. The EDT mode controlled by northward Ekman transport under the oscillating SH westerly winds generates a signal that propagates northward along the upper ocean and passes through the equator. The variation in the western boundary current (WBC) is much stronger in the North Atlantic than in the North Pacific, which appears to be associated with the relatively strong and persistent Mindanao Current (i.e., the southward flowing WBC of the North Pacific tropical gyre). The North Atlantic Deep Water (NADW) formation is controlled by salt advected northward by the North Atlantic WBC.

Seasonal Analysis of Air-Sea CO2 Flux Variability in the North Atlantic and the Southern Ocean 

2021 ◽  
Author(s):  
Paridhi Rustogi ◽  
Peter Landschuetzer ◽  
Sebastian Brune ◽  
Johanna Baehr
Keyword(s):  
Southern Ocean ◽  
Observational Data ◽  
North Atlantic ◽  
Seasonal Variability ◽  
Max Planck ◽  
Regional Patterns ◽  
Atlantic Basin ◽  
North Atlantic Basin ◽  
The North ◽  
The North Atlantic

<p>Understanding the variability and drivers of air-sea CO<span><sub>2</sub></span> fluxes on seasonal timescales is critical for resolving the ocean carbon sink's evolution and variability. Here, we investigate whether discrepancies in the representation of air-sea CO<span><sub>2</sub></span> fluxes on a seasonal timescale accumulate to influence the representation of CO<span><sub>2</sub></span> fluxes on an interannual timescale in two important ocean CO<span><sub>2 </sub></span>sink regions – the North Atlantic basin and the Southern Ocean. Using an observation-based product (SOM-FFN) as a reference, we investigate the representation of air-sea CO<span><sub>2</sub></span> fluxes in the Max Planck Institute's Earth System Model Grand Ensemble (MPI-ESM GE). Additionally, we include a simulation based on the same model configuration, where observational data from the atmosphere and ocean components is assimilated (EnKF assimilation) to verify if the inclusion of observational data alters the model state significantly and if the updated modelled CO<span><sub>2 </sub></span>flux values better represent observations.</p><p>We find agreement between all three observation-based and model products on an interannual timescale for the North Atlantic basin. However, the agreement on a seasonal timescale is inconsistent with discrepancies as large as 0.26 PgC/yr in boreal autumn in the North Atlantic. In the Southern Ocean, we find little agreement between the three products on an interannual basis with significant seasonal discrepancies as large as 1.71 PgC/yr in austral winter. However, while we identify regional patterns of dominating seasonal variability in MPI-GE and EnKF, we find that the SOM-FFN cannot demonstrate robust conclusions on the relevance of seasonal variability in the Southern Ocean. In turn, we cannot pin down the problems for this region.</p>

scholarly journals Erratum to “A Perspective on Stratigraphic, Vertically-Upward “Displacements or Dislocations” of Conodont-Elements: An Example From the Upper Devonian, Pre-Lithified, Black Shales of the Chattanooga Shale Formation In Tennessee, USA” ...

2019 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Michael Iannicelli
Keyword(s):  
Black Shale ◽  
Environmental Chemistry ◽  
Black Shales ◽  
Photic Zone ◽  
Marine Organic Matter ◽  
Chattanooga Shale ◽  
Shale Formation ◽  
Organic Matter Biomarkers ◽  
Reference Section ◽  
Made In

Even though the author already incorporated the citation of Sinninghe-Damste & Schouten (2006) into the text of the paper, the author regrets having failed to include their full citation within the Reference Section of my above paper which is: Sinninghe-Damste, J. S. & Schouton, S. (2006). Biological markers for anoxia in the photic zone of the water column. In, Volkman, J. K. (ed.), Marine Organic Matter: Biomarkers, Isotopes and DNA, (pp. 127 – 163). The Handbook of Environmental Chemistry, vol. 2N. Springer: Berlin and Heidelberg. https://doi.org/10.1007/698_2_005 The author also needs to paraphrase a statement made in the last three lines of the 2nd paragraph on page 40 where it reads as: “Thus, we may conclude here that paleo-upfreezing of any conodont-element(s) originally buried in the pre-lithified, light-colored shale occurred in order to account for their presence in black shale”. Instead, in lieu of that statement, it should read as “At this point in time of the study, we may tentatively conclude here while completely concluding later in the study, that conodont-elements originally existing in the underlying, pre-lithified, light-colored shale, had to paleo-upfreeze vertically upward into pre-lithified, black shale sediment in order to account for their presence in lithified black shale”.

The regional model of Subpolar Gyre based on NEMO 4

2021 ◽  
Author(s):  
Polina Verezemskaya ◽  
Bernard Barnier ◽  
Jean-Marc Molines ◽  
Sergey Gulev ◽  
Alexander Gavrikov
Keyword(s):  
North Atlantic ◽  
Initial Conditions ◽  
Regional Model ◽  
Ocean Modeling ◽  
The Arctic ◽  
Reliable Estimate ◽  
Circulation System ◽  
Subpolar Gyre ◽  
Vertical Coordinate ◽  
Denmark Strait

<p>A regional model of Subpolar Gyre in the North Atlantic is implemented. The NNATL12 model development aimed at a realistic representation of Subpolar Northern Atlantic's complex dynamics during the satellite era (starting from 1993 to nowadays) by using a high-resolution regional model that relies on the most up-to-date atmospheric and lateral forcing datasets and modeling techniques. Configuring this model, we focused on the representation of key processes in the Northern Atlantic, such as Irminger Rings, the boundary currents, deep convection, and convective eddies, dense waters cascading through the narrow straits between the Arctic and the Atlantic basins. NNATL12 model is based on NEMO4. The model domain covers the area between 47-70˚N and 84˚W-10˚E with a grid of 1/12˚ in horizontal and 75 vertical levels. In this region, the model is partially eddy-resolving. Three lateral open boundaries and initial conditions are set from the new GLORYS12 reanalysis (Lellouche et al., 2018). The surface forcing is provided by the new RAS NAAD dynamical hindcast based on the WRF model with a spatial resolution of 14 km (Gavrikov et al. 2020). The model adopted the most recent developments in the forced ocean modeling, such as upper boundary forcing schemes (Renault et al., 2020, Brodeau et al., 2016) and local-sigma vertical coordinate in the area of the overflows (Colombo et al., 2020). The model solution is sensitive to new parameterizations and vertical coordinate, which is demonstrated in various tests. The model provides a reliable estimate of the Subpolar North Atlantic circulation system at the surface and medium depth compared to observations. The model represents the ocean stratification at depths above 2000 m showing higher temperatures in the bottom of the Irminger Sea. At daily timescales, it is capable of representing the volume transport comparable to observed values. Irminger Rings TS-structure and dynamics are simulated consistent with the glider data. Comparing to the reanalysis model overestimates the March mixed layer depths and overextends the region of convection north. At the same time, the short-scale and decadal variability of MLD are reproduced by the model. Significant improvements of the deep stratification are obtained with the implementation of the local-sigma vertical coordinate. The model provides vertical profiles of temperature and salinity similar to the observed ones. However the Denmark Strait overflow waters are still too warm, but this is for a large part due to too warm waters at the sill. The high-frequency variability in the Denmark Strait is also in good accordance with the observations.</p>

I.—On the Eastern Margin of the North Atlantic Basin

1899 ◽  
Vol 6 (3) ◽  
pp. 97-105 ◽  
Author(s):  
Wilfrid H. Hudleston
Keyword(s):  
North Atlantic ◽  
Physical Geography ◽  
Point Of View ◽  
Atlantic Basin ◽  
Eastern Margin ◽  
North Atlantic Basin ◽  
The North ◽  
The North Atlantic

In offering a few remarks on a subject which belongs, in the first instance, to the province of physical geography, it will be necessary forme to point out certain hydrographical details, whilst, endeavouring to deduce from these details conclusions having a geological bearing. Oceanography is almost a science in itself, especially if we regard it from a geological point of view, as something more than a mere description of water-spaces and soundings. Ever since the days when the deep oceans were first explored for the purpose of laying the telegraph cables some of the leading facts were made known, and have since become familiar to all students of physical geography.

A Gateway to Ocean Circulation

2016 ◽  
Vol 46 (4) ◽  
pp. 429-459 ◽  
Author(s):  
Lino Camprubí ◽  
Sam Robinson
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
Western Mediterranean ◽  
Ocean Dynamics ◽  
Global Ocean ◽  
International Geophysical Year ◽  
The United Kingdom ◽  
Global Ocean Circulation ◽  
The Cold War ◽  
International Geophysical

The Strait of Gibraltar has a long tradition of political and scientific uniqueness. Twentieth-century submarine warfare added the ocean’s depth as a new dimension for those wanting to control and understand the Strait. During the Cold War the surveillance of this chokepoint became urgent and entangled with local disputes predating the two-blocs conflict, in particular the sovereignty of Gibraltar for which Spain and the United Kingdom competed. This paper explores a number of transnational research programs on ocean dynamics at the Strait and discovers a network of collaborating researchers who used, and went beyond, international institutions such the International Geophysical Year and NATO. In the process, the Western Mediterranean was constructed as a key maritime place for global ocean circulation, both as a factor to North Atlantic convection and as a model through which to understand it.

Northern source for Deglacial and Holocene deepwater composition changes in the Eastern North Atlantic Basin

2015 ◽  
Vol 425 ◽  
pp. 256-267 ◽  
Author(s):  
Janne Repschläger ◽  
Mara Weinelt ◽  
Nils Andersen ◽  
Dieter Garbe-Schönberg ◽  
Ralph Schneider
Keyword(s):  
North Atlantic ◽  
Atlantic Basin ◽  
North Atlantic Basin ◽  
Eastern North Atlantic ◽  
Composition Changes
Sign in / Sign up

Export Citation Format

Share Document