Origin, variability, and pathways of East Sea Intermediate Water in a high‐resolution ocean reanalysis

2021 ◽  
Author(s):  
Sang‐Yeob Kim ◽  
Young‐Gyu Park ◽  
Young Ho Kim ◽  
Seongbong Seo ◽  
Hyunkeun Jin ◽  
...  
Keyword(s):  
High Resolution ◽  
East Sea ◽  
Intermediate Water ◽  
Ocean Reanalysis

scholarly journals Regional circulation patterns of Mediterranean Outflow Water near the Iberian and African continental slopes

2019 ◽  
Author(s):  
Álvaro de Pascual-Collar ◽  
Marcos García-Sotillo ◽  
Bruno Levier ◽  
Roland Aznar ◽  
Pablo Lorente ◽  
...  
Keyword(s):  
High Resolution ◽  
North Atlantic ◽  
Deep Ocean ◽  
Intermediate Water ◽  
Mixing Processes ◽  
Ocean Reanalysis ◽  
Mediterranean Outflow Water ◽  
Circulation Patterns ◽  
Continental Slopes ◽  
Mediterranean Outflow

Abstract. The Mediterranean Outflow Water (MOW) is a dense water mass originated in the Gibraltar Straight. After exiting the Gulf of Cadiz, the MOW forms a reservoir region west of the Iberian continental slopes with a buoyant depth of approximately 1000 m depth. This region is a key role as the main centre where the MOW is mixed and distributed into the North Atlantic. The seafloor in this area is characterised by the presence of a complex bathymetry with three abyssal plains separated by mountain chains. Despite of this topographic features does not reach the surface, they influence ocean flows at intermediate and deep ocean layers conditioning the distribution and circulation of MOW. The CMEMS IBI ocean reanalysis is used to provide a detailed view of the circulation and mixing processes of MOW near the Iberian and African Continental slopes. This work emphasizes the relevance of the complex bathymetric features defining the circulation processes of MOW in this region. The high resolution of the IBI reanalysis allows to make a description of the meso-scale features forced by the topography. The temperature, salinity, velocity, transport, and vorticity fields are analysed to understand the circulation patterns of MOW. The high-resolution circulation patterns found reveals that Horseshoe Basin and the continental slope near Cape Ghir are key areas controlling the mixing processes of MOW with the surrounding waters mases, mainly North Atlantic Central Water (NACW), and Antarctic Intermediate Water (AAIW). The water masses variability is also analysed by means of composite analysis, results indicate the existence of a variability of the MOW tongue which retracts and expands westwards in opposition to the movement of the underlying North Atlantic Deep Water.

scholarly journals Occurrence and Evolution of Mesoscale Thermodynamic Phenomena in the Northern Part of the East Sea (Japan Sea) Derived from Satellite Altimeter Data

2021 ◽  
Vol 13 (6) ◽  
pp. 1071
Author(s):  
Taekyun Kim ◽  
Hyeong-Jun Jo ◽  
Jae-Hong Moon
Keyword(s):  
Japan Sea ◽  
Reanalysis Data ◽  
East Sea ◽  
Spatiotemporal Variability ◽  
Altimeter Data ◽  
Intermediate Water ◽  
Dipole Structure ◽  
Northwestern Region ◽  
New Perspective ◽  
Monsoon Winds

Based on satellite measurements and oceanic reanalysis data, it has been possible to investigate the spatiotemporal variability of the mesoscale phenomena in the northern part of the East Sea (NES) where direct observations of currents and hydrographical conditions are scarce. For the first time, this study identifies the detailed spatiotemporal structure of the mesoscale features in the NES and the mechanism of its occurrence and evolution, which have important consequences on the distribution of the intermediate water masses in the East Sea. Here, we show that mesoscale thermodynamic phenomena in the northwestern region of the East Sea are characterized by a dipole structure associated with positive and negative sea surface height anomalies. These result in a strong thermal gradient between the seasonally non-persistent anomalies, which emerge and strengthen during late fall and early winter. In contrast to the previous finding of the relationship between winter monsoon winds and mesoscale features in the NES, we found that this relationship is crucial only to the emergence of the mesoscale phenomena. Consequently, we present a new perspective on the evolution mechanism of the mesoscale features in the NES. Of direct significance to the present study, thermohaline transport into the northwestern region of the East Sea regulates the strengthening and weakening of mesoscale features in the NES. Wind forcing may contribute to the emergence of the mesoscale features in the NES and then the intensification of the mesoscale activities is attributed to the intrusion of warm and fresh surface water advected from the southern part of the East Sea.

scholarly journals THE BIFURCATION OF THE WESTERN BOUNDARY CURRENT SYSTEM OF THE SOUTH ATLANTIC OCEAN

2014 ◽  
Vol 32 (2) ◽  
pp. 241 ◽  
Author(s):  
Janini Pereira ◽  
Mariela Gabioux ◽  
Martinho Marta Almeida ◽  
Mauro Cirano ◽  
Afonso M. Paiva ◽  
...  
Keyword(s):  
High Resolution ◽  
Atlantic Ocean ◽  
Ocean Circulation ◽  
South Atlantic ◽  
Western Boundary Current ◽  
South Atlantic Ocean ◽  
Western Boundary ◽  
Intermediate Water ◽  
Boundary Current ◽  
The South

ABSTRACT. The results of two high-resolution ocean global circulation models – OGCMs (Hybrid Coordinate Ocean Model – HYCOM and Ocean Circulation andClimate Advanced Modeling Project – OCCAM) are analyzed with a focus on the Western Boundary Current (WBC) system of the South Atlantic Ocean. The volumetransports are calculated for different isopycnal ranges, which represent the most important water masses present in this region. The latitude of bifurcation of the zonalflows reaching the coast, which leads to the formation of southward or northward WBC flow at different depths (or isopycnal levels) is evaluated. For the Tropical Water,bifurcation of the South Equatorial Current occurs at 13◦-15◦S, giving rise to the Brazil Current, for the South Atlantic Central Water this process occurs at 22◦S.For the Antarctic Intermediate Water, bifurcation occurs near 28◦-30◦S, giving rise to a baroclinic unstable WBC at lower latitudes with a very strong vertical shearat mid-depths. Both models give similar results that are also consistent with previous observational studies. Observations of the South Atlantic WBC system havepreviously been sparse, consequently these two independent simulations which are based on realistic high-resolution OGCMs, add confidence to the values presentedin the literature regarding flow bifurcations at the Brazilian coast.Keywords: Southwestern Atlantic circulation, water mass, OCCAM, HYCOM. RESUMO. Resultados de dois modelos globais de alta resolução (HYCOM e OCCAM) são analisados focando o sistema de Corrente de Contorno Oeste do Oceano Atlântico Sul. Os transportes de volume são calculados para diferentes níveis isopicnais que representam as principais massas de água da região. É apresentada a avaliação da latitude de bifurcação do fluxo zonal que atinge a costa, permitindo a formação dos fluxos da Corrente de Contorno Oeste para o sul e para o norte emdiferentes níveis de profundidades (ou isopicnal). Para a Água Tropical, a bifurcação da Corrente Sul Equatorial ocorre entre 13◦-15◦S, originando a Corrente do Brasil, e para a Água Central do Atlântico Sul ocorre em 22◦S. A bifurcação daÁgua Intermediária Antártica ocorre próximo de 28◦-30◦S, dando um aumento na instabilidade baroclínica da Corrente de Contorno Oeste em baixas latitudes e com um forte cisalhamento vertical em profundidades intermediárias. Ambos os modelos apresentamresultados similares e consistentes com estudos observacionais prévios. Considerando que as observações do sistema de Corrente de Contorno Oeste do Atlântico Sul são escassas, essas duas simulações independentes com modelos globais de alta resolução adicionam confiança aos valores apresentados na literatura, relacionadosaos fluxos das bifurcações na costa do Brasil.Palavras-chave: circulação do Atlântico Sudoeste, massas de água, OCCAM, HYCOM.

scholarly journals Millennial-scale climate change and intermediate water circulation in the Bering Sea from 90 ka: A high-resolution record from IODP Site U1340

2013 ◽  
Vol 28 (1) ◽  
pp. 54-67 ◽  
Author(s):  
Shiloh A. Schlung ◽  
A. Christina Ravelo ◽  
Ivano W. Aiello ◽  
Dyke H. Andreasen ◽  
Mea S. Cook ◽  
...  
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Bering Sea ◽  
Water Circulation ◽  
Intermediate Water ◽  
The Bering Sea ◽  
Site U1340 ◽  
Millennial Scale

scholarly journals Anatomy of a Cyclonic Eddy in the Kuroshio Extension Based on High-Resolution Observations

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 553 ◽  
Author(s):  
Yongchui Zhang ◽  
Xi Chen ◽  
Changming Dong
Keyword(s):  
High Resolution ◽  
Mixed Layer ◽  
Kuroshio Extension ◽  
Mesoscale Eddies ◽  
Cyclonic Eddy ◽  
Intermediate Water ◽  
Dipole Structure ◽  
Significant Difference ◽  
The Kuroshio ◽  
Main Thermocline

Mesoscale eddies are common in the ocean and their surface characteristics have been well revealed based on altimetric observations. Comparatively, the knowledge of the three-dimensional (3D) structure of mesoscale eddies is scarce, especially in the open ocean. In the present study, high-resolution field observations of a cyclonic eddy in the Kuroshio Extension have been carried out and the anatomy of the observed eddy is conducted. The temperature anomaly exhibits a vertical monopole cone structure with a maximum of −7.3 °C located in the main thermocline. The salinity anomaly shows a vertical dipole structure with a fresh anomaly in the main thermocline and a saline anomaly in the North Pacific Intermediate Water (NPIW). The cyclonic flow displays an equivalent barotropic structure. The mixed layer is deep in the center of the eddy and thin in the periphery. The seasonal thermocline is intensified and the permanent thermocline is upward domed by 350 m. The subtropical mode water (STMW) straddled between the seasonal and permanent thermoclines weakens and dissipates in the eddy center. The salinity of NPIW distributed along the isopycnals shows no significant difference inside and outside the eddy. The geostrophic relation is approximately set up in the eddy. The nonlinearity—defined as the ratio between the rotational speed to the translational speed—is 12.5 and decreases with depth. The eddy-wind interaction is examined by high resolution satellite observations. The results show that the cold eddy induces wind stress aloft with positive divergence and negative curl. The wind induced upwelling process is responsible for the formation of the horizontal monopole pattern of salinity, while the horizontal transport results in the horizontal dipole structure of temperature in the mixed layer.

High resolution climate and environmental changes of the northern Japan (East) Sea for the last 40kyr inferred from sedimentary geochemical and pollen data

2014 ◽  
Vol 414 ◽  
pp. 260-272 ◽  
Author(s):  
Sergey A. Gorbarenko ◽  
Seung-Il Nam ◽  
Yulia V. Rybiakova ◽  
Xuefa Shi ◽  
Yanguang Liu ◽  
...  
Keyword(s):  
High Resolution ◽  
Environmental Changes ◽  
East Sea ◽  
Pollen Data ◽  
Northern Japan

Ba/Ca, P/Ca, Li/Ca and Mn/Ca ratios in the deep-sea bivalve Acesta excavata: Valuable tools to reconstruct plankton dynamics in cold-water coral ecosystems?

2020 ◽  
Author(s):  
Nicolai Schleinkofer ◽  
Jacek Raddatz ◽  
David Evans ◽  
Axel Gerdes ◽  
Silke Voigt ◽  
...  
Keyword(s):  
High Resolution ◽  
Cold Water ◽  
Environmental Parameters ◽  
Water Masses ◽  
Geochemical Data ◽  
Marine Bivalve ◽  
Intermediate Water ◽  
Inductively Coupled ◽  
Promising Tool ◽  
Water Coral

<p>Phytoplankton is one of the most important producers of oxygen, and plays an important role in the export of large amounts of carbon to the deeper ocean. Since phytoplankton is also the basis of most food webs in the ocean, understanding the dynamic system of phytoplankton is a crucial part to understand past carbon- and nutrient cycles and paleoclimatic changes. The export of nutrients is also an important factor impacting cold-water coral (CWC) reefs and may play a role in controlling their distribution. Here we present laser ablation inductively coupled mass spectrometer (LA-ICP-MS) Element/Ca measurements from Acesta excavata, a file clam, often associated with cold-water coral reefs along the European continental margin. Environmental parameters were recorded with lander systems directly deployed in the CWC reefs, which allows us to compare our geochemical data to in-situ ocean data.</p><p>Our results reveal, that Ba/Ca ratios show stable baseline values with intermittent sharp peaks. The location of these peaks in between major growth lines and temperature reconstructions with Mg/Sr ratios (Schleinkofer et al., submitted) show that these peaks occur during Winter and are repeatable between samples from the same location. This indicates a strong external forcing mechanism and allows cross-dating of different bivalve shells. While the occurrence of Ba/Ca peaks correlates with phytoplankton maxima, the absolute Ba/Ca ratio does not correlate with the phytoplankton abundance.</p><p>Mn/Ca ratios show similar trends as Ba/Ca ratios but the peaks are phase shifted and occur slightly delayed. These peaks could be triggered by decreasing oxygen concentrations in the water caused by the decomposition of organic material.</p><p>As A. excavata does not show easily distinguishable growth lines under the light microscope despite of Mutvei staining or fluorescence microscopy, we hypothesize that P/Ca ratios might be usable to locate highly phosphorylated shell areas that usually correlate with major growth lines. P/Ca ratios show no perceivable features in the vicinity of major growth lines. Instead we recognize that Ba/Ca peaks follow a minimum in P/Ca which is possibly caused by the uptake of phosphor by plankton.</p><p>These results suggest that A. excavata have potential as a promising tool for high resolution paleoenvironmental reconstructions of both intermediate and overlying surface water masses.</p><p>References</p><p>Schleinkofer N, Raddatz J, Evans D, Gerdes A, Flögel S, Voigt S, et al. Elemental to calcium ratios in the marine bivalve Acesta excavata: an archive for high-resolution paleoceanographic reconstructions of intermediate water masses. PLoS One. Submitted</p>

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