scholarly journals Supplementary material to "Assessment of the Finite VolumE Sea Ice Ocean Model (FESOM2.0), Part II: Partial bottom cells, embedded sea ice and vertical mixing library CVMIX"

Author(s):  
Patrick Scholz ◽  
Dmitry Sidorenko ◽  
Sergey Danilov ◽  
Qiang Wang ◽  
Nikolay Koldunov ◽  
...  
2021 ◽  
Author(s):  
Patrick Scholz ◽  
Dmitry Sidorenko ◽  
Sergey Danilov ◽  
Qiang Wang ◽  
Nikolay Koldunov ◽  
...  

Abstract. The second part of the assessment and evaluation of the unstructured-mesh Finite-volumE Sea ice-Ocean Model version 2.0 (FESOM2.0) is presented. It focuses on the performance of partial cells, embedded sea ice and on the effect of mixing parameterisations available through the CVMIX package. It is shown that partial cells and embedded sea ice lead to significant improvements in the representation of the Gulf Stream and North Atlantic Current as well as the circulation of the Arctic Ocean. In addition to the already existing Pacanowski and Phillander (fesom_PP) and K-profile (fesom_KPP) parameterisations for vertical mixing in FESOM2.0, we document the impact of several mixing parameterisations from the Community Vertical Mixing (CVMIX) project library. Among them are the CVMIX versions of Pacanowski and Phillander (cvmix_PP) and K-profile (cvmix_KPP) parameterisations, the tidal mixing parameterisation (cvmix_TIDAL), a vertical mixing parameterisation based on turbulent kinetic energy (cvmix_TKE) as well as a combination of cvmix_TKE and the recent scheme for the computation of the Internal Wave Dissipation, Energy and Mixing (IDEMIX). The IDEMIX parameterises the redistribution of internal wave energy through wave propagation, nonlinear interactions and the associated imprint on the vertical background diffusivity. Further, the benefit from using a parameterisation of sea ice melt season mixing in the surface layer (MOMIX) for reducing Southern Ocean hydrographic biases in FESOM2.0 is presented. We document the implementation of different model components and illustrate their behaviour. This paper serves primarily as a reference for FESOM users but is also useful to the broader modelling community.


2019 ◽  
Author(s):  
Patrick Scholz ◽  
Dmitry Sidorenko ◽  
Ozgur Gurses ◽  
Sergey Danilov ◽  
Nikolay Koldunov ◽  
...  

Abstract. The evaluation and model element description of the second version of the unstructured-mesh Finite-volumE Sea ice–Ocean circulation Model (FESOM2.0) is presented. The model sensitivity to arbitrary Lagrangian Eulerian (ALE) linear and nonlinear free surface formulation, Gent McWilliams eddy parameterisation, isoneutral Redi diffusion and different vertical mixing schemes is documented. The hydrographic biases, large scale circulation, numerical performance and scalability of FESOM2.0 are compared with its predecessor FESOM1.4. FESOM2.0 shows biases with a magnitude comparable to FESOM1.4 and it simulates a more realistic AMOC. Compared to its predecessor FESOM2.0 provides clearly defined fluxes and a three times higher throughput in terms of simulated years per day (SYPD). It is thus the first mature global unstructured-mesh ocean model with computational efficiency comparable to state-of-the-art structured-mesh ocean models. Other key elements of the model and new development will be described in following-up papers.


2019 ◽  
Vol 12 (11) ◽  
pp. 4875-4899 ◽  
Author(s):  
Patrick Scholz ◽  
Dmitry Sidorenko ◽  
Ozgur Gurses ◽  
Sergey Danilov ◽  
Nikolay Koldunov ◽  
...  

Abstract. The evaluation and model element description of the second version of the unstructured-mesh Finite-volumE Sea ice-Ocean Model (FESOM2.0) are presented. The new version of the model takes advantage of the finite-volume approach, whereas its predecessor version, FESOM1.4 was based on the finite-element approach. The model sensitivity to arbitrary Lagrangian–Eulerian (ALE) linear and nonlinear free-surface formulation, Gent–McWilliams eddy parameterization, isoneutral Redi diffusion and different vertical mixing schemes is documented. The hydrographic biases, large-scale circulation, numerical performance and scalability of FESOM2.0 are compared with its predecessor, FESOM1.4. FESOM2.0 shows biases with a magnitude comparable to FESOM1.4 and simulates a more realistic Atlantic meridional overturning circulation (AMOC). Compared to its predecessor, FESOM2.0 provides clearly defined fluxes and a 3 times higher throughput in terms of simulated years per day (SYPD). It is thus the first mature global unstructured-mesh ocean model with computational efficiency comparable to state-of-the-art structured-mesh ocean models. Other key elements of the model and new development will be described in follow-up papers.


2020 ◽  
Author(s):  
Dmitry Sidorenko ◽  
Sergey Danilov ◽  
Nikolay Koldunov ◽  
Patrick Scholz ◽  
Qiang Wang

Abstract. Computation of barotropic and meridional overturning streamfunctions for models formulated on unstructured meshes is commonly preceded by interpolation to a regular mesh. This operation destroys the original conservation which can be then artificially imposed to make the computation possible. An elementary method is proposed that avoids interpolation and preserves conservation in a strict model sense. The method is described as applied to the discretization of the Finite volumE Sea ice -- Ocean Model (FESOM2) on triangular meshes. It however is generalizable to collocated vertex based discretization on triangular meshes and to both triangular and hexagonal C-grid discretizations.


2021 ◽  
Author(s):  
Ozgur Gurses ◽  
Judith Hauck ◽  
Moritz Zeising ◽  
Laurent Oziel

<p>Marine biogeochemistry models are generally coupled to a physical ocean model. The biases in these coupled models can be attributed to simplified and empirical representation of biogeochemical processes, insufficient spatial mesh resolution which has an impact on the transport and mixing of biogeochemical substances in the ocean, and a deficit of physical parameterizations that intent to mimic unresolved processes such as eddies. Ocean Biogeochemical models based on variable mesh resolution proved to be convenient tools due to their computational efficiency and flexibility. Unlike standard structured-mesh ocean models, the mesh flexibility allows for a realistic representation of eddy dynamics in certain regions. Here, we present preliminary results of the coupling between the Finite-volumE Sea ice-Ocean Model (FESOM2.0) and the biogeochemical model REcoM2 (Regulated Ecosystem Model 2) in a coarse spatial resolution global configuration.<br>Surface maps of the simulated nutrients, chlorophyll a and net primary production (NPP) are comparable to available observational data sets. The control simulation forced with the JRA55-do data set reveals a realistic spatial distribution of nutrients, nanophytoplankton and diatom NPP, carbon stocks and fluxes. <br>FESOM2 utilizes a new dynamical core based on a finite-volume approach. The computational efficiency is about 2-3 times higher than the previous version FESOM1.4, whereas the quality of the simulated ocean and sea ice conditions and representation of biogeochemical variables are comparable in the two models. Thus, the new coupled model FESOM2- REcoM2 is very promising for ocean biogeochemical modelling applications.</p>


2020 ◽  
Author(s):  
Dmitry Sidorenko ◽  
Sergey Danilov ◽  
Nikolay Koldunov ◽  
Patrick Scholz

<p>The Atlantic meridional overturning circulation (AMOC) is the most common diagnostics of numerical simulations. Generally it is computed as a streamfunction of zonally averaged flow along the constant depth. More rarely it is computed as zonally averaged along constant isopycnals. The latter computation, however, allows one to better distinguish between water masses and physical processes contributing to the meridional transport. We analyze the AMOC in global simulations based on the Finite-volumE Sea ice–Ocean Model (FESOM 2.0) using eddy permitting to eddy resolving configurations in the North Atlantic. We (1) split the AMOC computed in density space into the constitutes induced by surface buoyancy fluxes and cross isopycnal transformations, (2) identify the water masses which contribute to the formation of the North Atlantic Deep Water and (3) study the AMOC response to the permitting or resolving eddies in the North Atlantic ocean.</p>


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