scholarly journals AMOC, Water Mass Transformations, and Their Responses to Changing Resolution in the Finite‐VolumE Sea Ice‐Ocean Model

2020 ◽  
Vol 12 (12) ◽  
Author(s):  
Dmitry Sidorenko ◽  
Sergey Danilov ◽  
Vera Fofonova ◽  
William Cabos ◽  
Nikolay Koldunov ◽  
...  
Keyword(s):  
Sea Ice ◽  
Finite Volume ◽  
Water Mass ◽  
Ocean Model ◽  
Water Mass Transformations

scholarly journals Simple algorithms to compute meridional overturning and barotropic streamfunction on unstructured meshes

2020 ◽  
Author(s):  
Dmitry Sidorenko ◽  
Sergey Danilov ◽  
Nikolay Koldunov ◽  
Patrick Scholz ◽  
Qiang Wang
Keyword(s):  
Sea Ice ◽  
Finite Volume ◽  
Unstructured Meshes ◽  
Ocean Model ◽  
Triangular Meshes ◽  
Elementary Method ◽  
Meridional Overturning

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.

Global ocean biogeochemical modelling with FESOM2-REcoM

2021 ◽  
Author(s):  
Ozgur Gurses ◽  
Judith Hauck ◽  
Moritz Zeising ◽  
Laurent Oziel
Keyword(s):  
Sea Ice ◽  
Finite Volume ◽  
Computational Efficiency ◽  
Ocean Model ◽  
Global Ocean ◽  
Biogeochemical Model ◽  
Coupled Models ◽  
Data Set ◽  
Biogeochemical Models ◽  
Mesh Resolution

<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>

AMOC response to changing resolution in the Finite-volumE Sea ice–Ocean Model

2020 ◽  
Author(s):  
Dmitry Sidorenko ◽  
Sergey Danilov ◽  
Nikolay Koldunov ◽  
Patrick Scholz
Keyword(s):  
Sea Ice ◽  
Finite Volume ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Ocean Model ◽  
Water Masses ◽  
Meridional Overturning Circulation ◽  
Meridional Transport ◽  
The North ◽  
The North Atlantic

<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>

scholarly journals Scalability and some optimization of the Finite-volumE Sea ice-Ocean Model, Version 2.0 (FESOM2)

2019 ◽  
Author(s):  
Nikolay V. Koldunov ◽  
Vadym Aizinger ◽  
Natalja Rakowsky ◽  
Patrick Scholz ◽  
Dmitry Sidorenko ◽  
...  
Keyword(s):  
Sea Ice ◽  
Finite Volume ◽  
Ocean Circulation ◽  
Circulation Model ◽  
Ocean Model ◽  
Special Focus ◽  
Climate Modelling ◽  
Parallel Scalability ◽  
Model Version ◽  
Version 2.0

Abstract. A study of the scalability of the Finite-volumE Sea ice-Ocean circulation Model, Version 2.0 (FESOM2), the first mature global model of its kind formulated on unstructured meshes, is presented. This study includes an analysis of main computational kernels with a special focus on bottlenecks in parallel scalability. Several model enhancements, improving this scalability for large numbers of processes, are described and tested. Model grids at different resolutions are used on four HPC systems with differing computation and communication hardware to demonstrate model's scalability and throughput. Furthermore, strategies for improvements in parallel performance are presented and assessed. We show that in terms of throughput FESOM2.0 is on par with the state-of-the-art structured ocean models and in realistic eddy resolving configuration (1/10° resolution) can produce about 16 years per day on 14 000 cores. This suggests that unstructured-mesh models are becoming extremely competitive tools in high-resolution climate modelling. It is shown that main bottlenecks of FESOM parallel scalability are the two-dimensional components of the model, namely the computations of external (barotropic) mode and the sea-ice model. It is argued that these bottlenecks are shared with other general ocean circulation models.

scholarly journals Intercomparison of Antarctic ice-shelf, ocean, and sea-ice interactions simulated by MetROMS-iceshelf and FESOM 1.4

2018 ◽  
Vol 11 (4) ◽  
pp. 1257-1292 ◽  
Author(s):  
Kaitlin A. Naughten ◽  
Katrin J. Meissner ◽  
Benjamin K. Galton-Fenzi ◽  
Matthew H. England ◽  
Ralph Timmermann ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Water Mass ◽  
Horizontal Resolution ◽  
Ocean Model ◽  
Small Scale ◽  
Ice Shelf ◽  
Vertical Coordinate ◽  
Ice Shelves ◽  
Basal Melting

Abstract. An increasing number of Southern Ocean models now include Antarctic ice-shelf cavities, and simulate thermodynamics at the ice-shelf/ocean interface. This adds another level of complexity to Southern Ocean simulations, as ice shelves interact directly with the ocean and indirectly with sea ice. Here, we present the first model intercomparison and evaluation of present-day ocean/sea-ice/ice-shelf interactions, as simulated by two models: a circumpolar Antarctic configuration of MetROMS (ROMS: Regional Ocean Modelling System coupled to CICE: Community Ice CodE) and the global model FESOM (Finite Element Sea-ice Ocean Model), where the latter is run at two different levels of horizontal resolution. From a circumpolar Antarctic perspective, we compare and evaluate simulated ice-shelf basal melting and sub-ice-shelf circulation, as well as sea-ice properties and Southern Ocean water mass characteristics as they influence the sub-ice-shelf processes. Despite their differing numerical methods, the two models produce broadly similar results and share similar biases in many cases. Both models reproduce many key features of observations but struggle to reproduce others, such as the high melt rates observed in the small warm-cavity ice shelves of the Amundsen and Bellingshausen seas. Several differences in model design show a particular influence on the simulations. For example, FESOM's greater topographic smoothing can alter the geometry of some ice-shelf cavities enough to affect their melt rates; this improves at higher resolution, since less smoothing is required. In the interior Southern Ocean, the vertical coordinate system affects the degree of water mass erosion due to spurious diapycnal mixing, with MetROMS' terrain-following coordinate leading to more erosion than FESOM's z coordinate. Finally, increased horizontal resolution in FESOM leads to higher basal melt rates for small ice shelves, through a combination of stronger circulation and small-scale intrusions of warm water from offshore.

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