scholarly journals Modeling of the Turkish Strait System Using a High Resolution Unstructured Grid Ocean Circulation Model

2021 ◽  
Vol 9 (7) ◽  
pp. 769
Author(s):  
Mehmet Ilicak ◽  
Ivan Federico ◽  
Ivano Barletta ◽  
Sabri Mutlu ◽  
Haldun Karan ◽  
...  
Keyword(s):  
High Resolution ◽  
Ocean Circulation ◽  
Layer Structure ◽  
Circulation Model ◽  
Open Boundary ◽  
The Black Sea ◽  
Leeward Side ◽  
Marmara Sea ◽  
Open Boundary Conditions ◽  
Bosphorus Strait

The Turkish Strait System, which is the only connection between the Black Sea and the Mediterranean Sea, is a challenging region for ocean circulation models due to topographic constraints and water mass structure. We present a newly developed high resolution unstructured finite element grid model to simulate the Turkish Strait System using realistic atmospheric forcing and lateral open boundary conditions. We find that the jet flowing from the Bosphorus Strait into the Marmara creates an anticyclonic circulation. The eddy kinetic energy field is high around the jets exiting from the Bosphorus Strait, Dardanelles Strait, and also the leeward side of the islands in the Marmara Sea. The model successfully captures the two-layer structure of the Sea of Marmara. The volume transport at the Bosphorus is around 120 km3/year which is consistent with the recent observations. The largest bias in the model is at the interface depth due to the shallower mixed layer.

scholarly journals A Model of Black Sea Circulation with Strait Exchange (2008–2018)

2019 ◽  
Author(s):  
Murat Gunduz ◽  
Emin Özsoy ◽  
Robinson Hordoir
Keyword(s):  
Black Sea ◽  
Lower Layer ◽  
Circulation Model ◽  
Open Boundary ◽  
The Black Sea ◽  
Marmara Sea ◽  
Open Boundary Conditions ◽  
Medium Resolution ◽  
Water Mass Formation ◽  
High Space

Abstract. The Bosphorus exchange is of critical importance for hydrodynamics of the Black Sea. In this study, we report on the development of a medium resolution circulation model of the Black Sea, making use of up-to-date topography, atmospheric forcing with high space and time resolution, climatic river fluxes and strait exchange enabled by adding the Bosphorus Strait with an artificial box on the Marmara Sea side. Particular attention is given to circulation, mixing, convective water mass formation processes compared with observations. The present formulation with temperature and salinity relaxed to the observed seasonal climatology of the Marmara box and open boundary conditions are found to enable Bosphorus exchange with upper, lower layer and net fluxes comparable to the observed range. This in turn enables to capture the trend of rapid climatic change observed in the Black Sea in the last decade.

scholarly journals A model of Black Sea circulation with strait exchange (2008–2018)

2020 ◽  
Vol 13 (1) ◽  
pp. 121-138 ◽  
Author(s):  
Murat Gunduz ◽  
Emin Özsoy ◽  
Robinson Hordoir
Keyword(s):  
Black Sea ◽  
Lower Layer ◽  
Climatic Variability ◽  
Circulation Model ◽  
Open Boundary ◽  
The Black Sea ◽  
Marmara Sea ◽  
Open Boundary Conditions ◽  
Medium Resolution ◽  
High Space

Abstract. The Bosphorus exchange is of critical importance for hydrodynamics and hydroclimatology of the Black Sea. In this study, we report on the development of a medium-resolution circulation model of the Black Sea, making use of surface atmospheric forcing with high space and time resolution, climatic river fluxes and strait exchange, enabled by adding elementary details of strait and coastal topography and seasonal hydrology specified in an artificial box on the Marmara Sea side. Particular attention is given to circulation, mixing and convective water mass formation processes in the model, which are then compared with observations. Open boundary conditions relaxed to seasonal hydrology specified in the artificial box are found to enable Bosphorus exchange with a proper upper layer, lower layer and net fluxes comparable to the observed ranges. These improvements at the artificial boundary and in the interior evolution of the Black Sea allow the study to capture daily, seasonal to decadal climatic variability and change observed in the Black Sea in the last few decades.

scholarly journals Tidally induced lateral dispersion of the Storfjorden overflow plume

Ocean Science ◽  
2013 ◽  
Vol 9 (5) ◽  
pp. 885-899 ◽  
Author(s):  
F. Wobus ◽  
G. I. Shapiro ◽  
J. M. Huthnance ◽  
M. A. M. Maqueda ◽  
Y. Aksenov
Keyword(s):  
Ocean Circulation ◽  
Circulation Model ◽  
Bottom Layer ◽  
Horizontal Resolution ◽  
Open Boundary ◽  
Coastal Current ◽  
Fram Strait ◽  
Open Boundary Conditions ◽  
Shear Dispersion ◽  
Set Up

Abstract. We investigate the flow of brine-enriched shelf water from Storfjorden (Svalbard) into Fram Strait and onto the western Svalbard Shelf using a regional set-up of NEMO-SHELF, a 3-D numerical ocean circulation model. The model is set up with realistic bathymetry, atmospheric forcing, open boundary conditions and tides. The model has 3 km horizontal resolution and 50 vertical levels in the sh-coordinate system which is specially designed to resolve bottom boundary layer processes. In a series of modelling experiments we focus on the influence of tides on the propagation of the dense water plume by comparing results from tidal and non-tidal model runs. Comparisons of non-tidal to tidal simulations reveal a hotspot of tidally induced horizontal diffusion leading to the lateral dispersion of the plume at the southernmost headland of Spitsbergen which is in close proximity to the plume path. As a result the lighter fractions in the diluted upper layer of the plume are drawn into the shallow coastal current that carries Storfjorden water onto the western Svalbard Shelf, while the dense bottom layer continues to sink down the slope. This bifurcation of the plume into a diluted shelf branch and a dense downslope branch is enhanced by tidally induced shear dispersion at the headland. Tidal effects at the headland are shown to cause a net reduction in the downslope flux of Storfjorden water into the deep Fram Strait. This finding contrasts previous results from observations of a dense plume on a different shelf without abrupt topography.

scholarly journals Modeling <i>p</i>CO<sub>2</sub> variability in the Gulf of Mexico

2016 ◽  
Vol 13 (15) ◽  
pp. 4359-4377 ◽  
Author(s):  
Zuo Xue ◽  
Ruoying He ◽  
Katja Fennel ◽  
Wei-Jun Cai ◽  
Steven Lohrenz ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Ocean Circulation ◽  
Inorganic Carbon ◽  
Circulation Model ◽  
Global Ocean ◽  
Open Boundary ◽  
Biogeochemical Model ◽  
Open Boundary Conditions ◽  
Model Simulations ◽  
Co2 Sink

Abstract. A three-dimensional coupled physical–biogeochemical model was used to simulate and examine temporal and spatial variability of sea surface pCO2 in the Gulf of Mexico (GoM). The model was driven by realistic atmospheric forcing, open boundary conditions from a data-assimilative global ocean circulation model, and observed freshwater and terrestrial nutrient and carbon input from major rivers. A 7-year model hindcast (2004–2010) was performed and validated against ship measurements. Model results revealed clear seasonality in surface pCO2 and were used to estimate carbon budgets in the Gulf. Based on the average of model simulations, the GoM was a net CO2 sink with a flux of 1.11 ± 0.84  ×  1012 mol C yr−1, which, together with the enormous fluvial inorganic carbon input, was comparable to the inorganic carbon export through the Loop Current. Two model sensitivity experiments were performed: one without biological sources and sinks and the other using river input from the 1904–1910 period as simulated by the Dynamic Land Ecosystem Model (DLEM). It was found that biological uptake was the primary driver making GoM an overall CO2 sink and that the carbon flux in the northern GoM was very susceptible to changes in river forcing. Large uncertainties in model simulations warrant further process-based investigations.

scholarly journals Modeling ocean circulation and biogeochemical variability in the Gulf of Mexico

2013 ◽  
Vol 10 (11) ◽  
pp. 7219-7234 ◽  
Author(s):  
Z. Xue ◽  
R. He ◽  
K. Fennel ◽  
W.-J. Cai ◽  
S. Lohrenz ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Ocean Circulation ◽  
Function Analysis ◽  
Inorganic Nitrogen ◽  
Circulation Model ◽  
Deep Ocean ◽  
Global Ocean ◽  
Open Boundary ◽  
Biogeochemical Model ◽  
Open Boundary Conditions

Abstract. A three-dimensional coupled physical-biogeochemical model is applied to simulate and examine temporal and spatial variability of circulation and biogeochemical cycling in the Gulf of Mexico (GoM). The model is driven by realistic atmospheric forcing, open boundary conditions from a data assimilative global ocean circulation model, and observed freshwater and terrestrial nitrogen input from major rivers. A 7 yr model hindcast (2004–2010) was performed, and validated against satellite observed sea surface height, surface chlorophyll, and in situ observations including coastal sea level, ocean temperature, salinity, and dissolved inorganic nitrogen (DIN) concentration. The model hindcast revealed clear seasonality in DIN, phytoplankton and zooplankton distributions in the GoM. An empirical orthogonal function analysis indicated a phase-locked pattern among DIN, phytoplankton and zooplankton concentrations. The GoM shelf nitrogen budget was also quantified, revealing that on an annual basis the DIN input is largely balanced by the removal through denitrification (an equivalent of ~ 80% of DIN input) and offshore exports to the deep ocean (an equivalent of ~ 17% of DIN input).

scholarly journals Modeling ocean circulation and biogeochemical variability in the Gulf of Mexico

2013 ◽  
Vol 10 (5) ◽  
pp. 7785-7830 ◽  
Author(s):  
Z. Xue ◽  
R. He ◽  
K. Fennel ◽  
W.-J. Cai ◽  
S. Lohrenz ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Ocean Circulation ◽  
Function Analysis ◽  
Circulation Model ◽  
Deep Ocean ◽  
Global Ocean ◽  
Open Boundary ◽  
Biogeochemical Model ◽  
Open Boundary Conditions ◽  
Nutrient Input

Abstract. A three-dimensional coupled physical-biogeochemical model is applied to simulate and examine temporal and spatial variability of circulation and biogeochemical cycling in the Gulf of Mexico (GoM). The model is driven by realistic atmospheric forcing, open boundary conditions from a data assimilative global ocean circulation model, and observed freshwater and terrestrial nutrient input from major rivers. A 7 yr model hindcast (2004–2010) was performed, and validated against satellite observed sea surface height, surface chlorophyll, and in-situ observations including coastal sea-level, ocean temperature, salinity, and nutrient concentration. The model hindcast revealed clear seasonality in nutrient, phytoplankton and zooplankton distributions in the GoM. An Empirical Orthogonal Function analysis indicated a phase-locked pattern among nutrient, phytoplankton and zooplankton concentrations. The GoM shelf nutrient budget was also quantified, revealing that on an annual basis ~80% of nutrient input was denitrified on the shelf and ~17% was exported to the deep ocean.

scholarly journals Tidally-induced lateral dispersion of the Storfjorden overflow plume

2013 ◽  
Vol 10 (2) ◽  
pp. 691-726
Author(s):  
F. Wobus ◽  
G. I. Shapiro ◽  
J. M. Huthnance ◽  
M. A. M. Maqueda ◽  
Y. Aksenov
Keyword(s):  
Ocean Circulation ◽  
Circulation Model ◽  
Bottom Layer ◽  
Horizontal Resolution ◽  
Open Boundary ◽  
Coastal Current ◽  
Fram Strait ◽  
Open Boundary Conditions ◽  
Shear Dispersion ◽  
Set Up

Abstract. We investigate the flow of brine-enriched shelf water from Storfjorden (Svalbard) into Fram Strait and onto the Western Svalbard Shelf using a regional setup of NEMO-SHELF, a 3-D numerical ocean circulation model. The model is set up with realistic bathymetry, atmospheric forcing, open boundary conditions and tides. The model has 3 km horizontal resolution and 50 vertical levels in the sh-coordinate system which is specially designed to resolve bottom boundary layer processes. In a series of modelling experiments we focus on the influence of tides on the propagation of the dense water plume by comparing results from tidal and non-tidal model runs. Comparisons of non-tidal to tidal simulations reveal a hotspot of tidally-induced horizontal diffusion leading to the lateral dispersion of the plume at the southernmost headland of Spitsbergen which is in close proximity to the plume path. As a result the lighter fractions in the diluted upper layer of the plume are drawn into the shallow coastal current that carries Storfjorden water onto the Western Svalbard Shelf, while the dense bottom layer continues to sink down the slope. This bifurcation of the plume into a diluted shelf branch and a dense downslope branch is enhanced by tidally-induced shear dispersion at the headland. Tidal effects at the headland are shown to cause a net reduction in the downslope flux of Storfjorden water into deep Fram Strait. This finding contrasts previous results from observations of a dense plume on a different shelf without abrupt topography.

Tools and technologies for NEMO models: the case of the Generic Interfaces developed in the framework of IMMERSE

2021 ◽  
Author(s):  
Laura Stefanizzi ◽  
Stefania Ciliberti ◽  
Mehmet Ilicak ◽  
Giovanni Coppini
Keyword(s):  
Boundary Conditions ◽  
Black Sea ◽  
Numerical Solutions ◽  
Initial Boundary ◽  
Coastal Ocean ◽  
Open Boundary ◽  
The Black Sea ◽  
Marmara Sea ◽  
Open Boundary Conditions ◽  
Model Configuration

&lt;p&gt;Setting new model configurations based on NEMO requires the definition of initial/boundary condition and the validation of numerical solutions. In the framework of IMMERSE H2020 project, CMCC is developing new tools and technological capacities for handling in easy and reliable way external products, such CMEMS or coastal ocean data, for research-to-operations applications. Generic Interfaces for NEMO (InterNEMO) allow for 3 main scopes: 1) to access and discover the CMEMS catalogue, including both model and observational data; 2) to manipulate accessed datasets, including coastal ocean data, to extract relevant physical information to use for setting initial/boundary conditions for a new NEMO-based configurations; 3) to prepare NEMO set of upstream files and to validate NEMO solution by using CMEMS observational datasets. InterNEMO implements also technologies to connect a NEMO user to Wekeo DIAS (https://www.wekeo.eu/) for the interoperable accessing and processing of CMEMS data. In this contribution, we present the InterNEMO architecture developed in Python via Jupyter Notebooks, to support the user/researcher to easily discover, design and configure modeling components required by the new NEMO-based configuration. InterNEMO is tested for the Black Sea hydrodynamical model configuration, developed by CMCC in the framework of the Black Sea Monitoring and Forecasting Centre (BS-MFC) for CMEMS a) to show how to access CMEMS observations through Wekeo DIAS and use them to validate numerical solutions and b) to define open boundary conditions from an unstructured grid model configuration based on Shyfem, developed for the Marmara Sea.&lt;/p&gt;

scholarly journals Modeling <i>p</i>CO<sub>2</sub> variability in the Gulf of Mexico

2014 ◽  
Vol 11 (8) ◽  
pp. 12673-12695 ◽  
Author(s):  
Z. Xue ◽  
R. He ◽  
K. Fennel ◽  
W.-J. Cai ◽  
S. Lohrenz ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Ocean Circulation ◽  
Circulation Model ◽  
Global Ocean ◽  
Open Boundary ◽  
Biogeochemical Model ◽  
Loop Current ◽  
Open Boundary Conditions ◽  
Sensitivity Experiment ◽  
Co2 Sink

Abstract. A three-dimensional coupled physical–biogeochemical model was used to simulate and examine temporal and spatial variability of surface pCO2 in the Gulf of Mexico (GoM). The model is driven by realistic atmospheric forcing, open boundary conditions from a data-assimilative global ocean circulation model, and observed freshwater and terrestrial nutrient and carbon input from major rivers. A seven-year model hindcast (2004–2010) was performed and was validated against in situ measurements. The model revealed clear seasonality in surface pCO2. Based on the multi-year mean of the model results, the GoM is an overall CO2 sink with a flux of 1.34 × 1012 mol C yr−1, which, together with the enormous fluvial carbon input, is balanced by the carbon export through the Loop Current. A sensitivity experiment was performed where all biological sources and sinks of carbon were disabled. In this simulation surface pCO2 was elevated by ~ 70 ppm, providing the evidence that biological uptake is a primary driver for the observed CO2 sink. The model also provided insights about factors influencing the spatial distribution of surface pCO2 and sources of uncertainty in the carbon budget.

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