scholarly journals 3D dynamics of the Southeastern North Sea, effects of variable resolution

2019 ◽  
Author(s):  
Ivan Kuznetsov ◽  
Alexey Androsov ◽  
Vera Fofonova ◽  
Sergey Danilov ◽  
Natalja Rakowsky ◽  
...  
Keyword(s):  
North Sea ◽  
Three Dimensional ◽  
Horizontal Resolution ◽  
Open Boundary ◽  
Small Scale ◽  
Southeastern Part ◽  
Wetting And Drying ◽  
The North ◽  
Open Sea ◽  
Mesh Resolution

Abstract. A newly developed coastal model FESOM-C based on three-dimensional unstructured meshes and finite volume is applied to simulate dynamics of the southeastern part of the North Sea. Variable horizontal resolution enables using meshes that are coarse in the open sea but refined in the shallow areas (which include the Wadden Sea and the estuaries) to resolve important small-scale process (such as wetting and drying, sub-mesoscales eddies and dynamics of steep coastal fronts). Model results for the simulation for the period between January 2010 and December 2014 agree reasonably well with data from numerous autonomous observation stations with high temporal and spatial resolution, located in the region, data from ferry boxes and glider expeditions. The analysis of numerical solution convergence on meshes with different horizontal resolutions allows identifying areas where high mesh resolution (wetting and drying zones, shallow areas) and low mesh resolution (open boundary, open sea, and deep regions) are optimal for numerical simulations.

scholarly journals Evaluation and Application of Newly Designed Finite Volume Coastal Model FESOM-C, Effect of Variable Resolution in the Southeastern North Sea

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1412
Author(s):  
Ivan Kuznetsov ◽  
Alexey Androsov ◽  
Vera Fofonova ◽  
Sergey Danilov ◽  
Natalja Rakowsky ◽  
...  
Keyword(s):  
Finite Volume ◽  
North Sea ◽  
Three Dimensional ◽  
Horizontal Resolution ◽  
Open Boundary ◽  
Small Scale ◽  
Wetting And Drying ◽  
Open Sea ◽  
Mesh Resolution ◽  
Coarse Meshes

A newly developed coastal model, FESOM-C, based on three-dimensional unstructured meshes and finite volume, is applied to simulate the dynamics of the southeastern North Sea. Variable horizontal resolution enables coarse meshes in the open sea with refined meshes in shallow areas including the Wadden Sea and estuaries to resolve important small-scale processes such as wetting and drying, sub-mesoscale eddies, and the dynamics of steep coastal fronts. Model results for a simulation of the period from January 2010 to December 2014 agree reasonably well with data from numerous regional autonomous observation stations with high temporal and spatial resolutions, as well as with data from FerryBoxes and glider expeditions. Analyzing numerical solution convergence on meshes of different horizontal resolutions allows us to identify areas where high mesh resolution (wetting and drying zones and shallow areas) and low mesh resolution (open boundary, open sea, and deep regions) are optimal for numerical simulations.

scholarly journals The effects of climate change on persistent organic pollutants (POPs) in the North Sea

2013 ◽  
Vol 10 (5) ◽  
pp. 1525-1557
Author(s):  
K. O'Driscoll ◽  
B. Mayer ◽  
J. Su ◽  
M. Mathis
Keyword(s):  
Climate Change ◽  
Organic Pollutants ◽  
North Sea ◽  
21St Century ◽  
Persistent Organic Pollutants ◽  
Global Ocean ◽  
Open Boundary ◽  
The North ◽  
The Future ◽  
The North Sea

Abstract. The fate and cycling of two selected legacy persistent organic pollutants (POPs), PCB 153 and γ-HCH, in the North Sea in the 21st century have been modelled with combined hydrodynamic and fate and transport ocean models. To investigate the impact of climate variability on POPs in the North Sea in the 21st century, future scenario model runs for three 10 yr periods to the year 2100 using plausible levels of both in situ concentrations and atmospheric, river and open boundary inputs are performed. Since estimates of future concentration levels of POPs in the atmosphere, oceans and rivers are not available, our approach was to reutilise 2005 values in the atmosphere, rivers and at the open ocean boundaries for every year of the simulations. In this way, we attribute differences between the three 10 yr simulations to climate change only. For the HAMSOM and atmospheric forcing, results of the IPCC A1B (SRES) 21st century scenario are utilised, where surface forcing is provided by the REMO downscaling of the ECHAM5 global atmospheric model, and open boundary conditions are provided by the MPIOM global ocean model. Dry gas deposition and volatilisation of γ-HCH increase in the future relative to the present. In the water column, total mass of γ-HCH and PCB 153 remain fairly steady in all three runs. In sediment, γ-HCH increases in the future runs, relative to the present, while PCB 153 in sediment decreases exponentially in all three runs, but even faster in the future, both of which are the result of climate change. Annual net sinks exceed sources at the ends of all periods.

scholarly journals Dynamics of Orographically Triggered Banded Convection in Sheared Moist Orographic Flows

2007 ◽  
Vol 64 (10) ◽  
pp. 3542-3561 ◽  
Author(s):  
Oliver Fuhrer ◽  
Christoph Schär
Keyword(s):  
Small Amplitude ◽  
Three Dimensional ◽  
Horizontal Resolution ◽  
Small Scale ◽  
Mean Flow ◽  
Topographic Roughness ◽  
Wide Range ◽  
Orographic Convection ◽  
Wind Profiles

Abstract Shallow orographic convection embedded in an unstable cap cloud can organize into convective bands. Previous research has highlighted the important role of small-amplitude topographic variations in triggering and organizing banded convection. Here, the underlying dynamical mechanisms are systematically investigated by conducting three-dimensional simulations of moist flows past a two-dimensional mountain ridge using a cloud-resolving numerical model. Most simulations address a sheared environment to account for the observed wind profiles. Results confirm that small-amplitude topographic variations can enhance the development of embedded convection and anchor quasi-stationary convective bands to a fixed location in space. The resulting precipitation patterns exhibit tremendous spatial variability, since regions receiving heavy rainfall can be only kilometers away from regions receiving little or no rain. In addition, the presence of banded convection has important repercussions on the area-mean precipitation amounts. For the experimental setup here, the gravity wave response to small-amplitude topographic variations close to the upstream edge of the cap cloud (which is forced by the larger-scale topography) is found to be the dominant triggering mechanism. Small-scale variations in the underlying topography are found to force the location and spacing of convective bands over a wide range of scales. Further, a self-sufficient mode of unsteady banded convection is investigated that does not dependent on external perturbations and is able to propagate against the mean flow. Finally, the sensitivity of model simulations of banded convection with respect to horizontal computational resolution is investigated. Consistent with predictions from a linear stability analysis, convective bands of increasingly smaller scales are favored as the horizontal resolution is increased. However, small-amplitude topographic roughness is found to trigger banded convection and to control the spacing and location of the resulting bands. Thereby, the robustness of numerical simulations with respect to an increase in horizontal resolution is increased in the presence of topographic variations.

Morphology of the cephalothorax integument of Bryocamptus pygmaeus (Copepoda: Harpacticoida: Canthocamptidae), based on a new research method

2021 ◽  
Vol 30 (2) ◽  
pp. 320-330
Author(s):  
A.A. Novikov ◽  
E.B. Fefilova
Keyword(s):  
Three Dimensional ◽  
Komi Republic ◽  
Southeastern Part ◽  
The North ◽  
Udmurt Republic ◽  
The Republic ◽  
A New Technique ◽  
Three Dimensional Models ◽  
New Research ◽  
First Time

The number and location of sensilla and pores of the cephalothorax integument of the species Bryocamptus pygmaeus (G.O. Sars, 1863) (Copepoda, Canthocamptidae) were studied for the first time on the material from several European regions: the southeastern part of the Bolshezemelskaya tundra (Ne­nets Autonomous District), the north of the Komi Republic, the Republic of Karelia, and the central part of European Russia (Udmurt Republic). In the samples examined, two groups of populations differing in the characters of cephalothorax integument were recognised. These differences were found to correlate with the variability of the endopod of fourth pair of female legs, which bears four setae in specimens of the eastern form, while a specimen examined from Karelia has five setae. Pore maps are composed for both groups of morphotypes. A statistical analysis was carried out based on a new technique using three-dimensional models of the cephalothorax. As a result of this analysis, a high similarity between individuals of the eastern form and differences of the latter from the Karelian specimen were revealed.

scholarly journals AMM15: a new high-resolution NEMO configuration for operational simulation of the European north-west shelf

2018 ◽  
Vol 11 (2) ◽  
pp. 681-696 ◽  
Author(s):  
Jennifer A. Graham ◽  
Enda O'Dea ◽  
Jason Holt ◽  
Jeff Polton ◽  
Helene T. Hewitt ◽  
...  
Keyword(s):  
High Resolution ◽  
Horizontal Resolution ◽  
Bias Reduction ◽  
Small Scale ◽  
Operational System ◽  
North West ◽  
The North ◽  
European North ◽  
The Mean ◽  
Mean State

Abstract. This paper describes the next-generation ocean forecast model for the European north-west shelf, which will become the basis of operational forecasts in 2018. This new system will provide a step change in resolution and therefore our ability to represent small-scale processes. The new model has a resolution of 1.5 km compared with a grid spacing of 7 km in the current operational system. AMM15 (Atlantic Margin Model, 1.5 km) is introduced as a new regional configuration of NEMO v3.6. Here we describe the technical details behind this configuration, with modifications appropriate for the new high-resolution domain. Results from a 30-year non-assimilative run using the AMM15 domain demonstrate the ability of this model to represent the mean state and variability of the region.Overall, there is an improvement in the representation of the mean state across the region, suggesting similar improvements may be seen in the future operational system. However, the reduction in seasonal bias is greater off-shelf than on-shelf. In the North Sea, biases are largely unchanged. Since there has been no change to the vertical resolution or parameterization schemes, performance improvements are not expected in regions where stratification is dominated by vertical processes rather than advection. This highlights the fact that increased horizontal resolution will not lead to domain-wide improvements. Further work is needed to target bias reduction across the north-west shelf region.

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