A 4.5 km resolution Arctic Ocean simulation with the global multi-resolution model FESOM1.4

Abstract

Abstract. In the framework of developing a global modeling system which can facilitate modeling studies on Arctic Ocean and high-mid latitude linkage, we evaluate the Arctic Ocean simulated by the multi-resolution ocean sea-ice model FESOM.To explore the value of using high horizontal resolution for Arctic Ocean modeling, we use two global meshes differing in Atlantic Water (AW) mean state and variability. The deepening and thickening bias of the AW layer, a common issue found in coarse resolution simulations, is significantly alleviated by using higher resolution. The topographic steering of the AW is stronger and the seasonal and interannual temperature variability along the ocean bottom topography is enhanced in the high resolution simulation. The high resolution also improves the ocean surface circulation, mainly through a better representation of the narrow straits in the Canadian Arctic Archipelago (CAA). The representation of CAA throughflow not only influences 10 the release of water masses through the other gateways, but also the circulation pathways inside the Arctic Ocean. However, the mean state and variability of Arctic freshwater content and the variability of freshwater transport through the Arctic gateways appear not to be very sensitive to the increase in resolution employed here. We also discuss model issues that are not directly linked to resolution, highlighting the need for further model development including improving parameterizations.

The Relative Influence of Atmospheric and Oceanic Model Resolution on the Circulation of the North Atlantic Ocean in a Coupled Climate Model

“…Increasing ocean model resolution in ocean models has a critical impact on the role that eddies play in the ocean heat budget and in the dynamics of major frontal systems (see, e.g., Iovino et al, ; Von Storch et al, ). Enhanced resolution improves the representation of narrow boundary currents (e.g., Marzocchi et al, ; Sein et al, ; Wang et al, ) and the connectivity between ocean basins (e.g., Chang et al, ). Increases of resolution in atmosphere‐only models have also beneficial impacts on many aspects of the large‐scale circulation and lead to a more realistic simulation of regional climate and small‐scale phenomena (Jung et al, , and Haarsma et al, , for a comprehensive review).…”

Sensitivity of the Arctic freshwater content and transport to model resolution

“…According to Jahn et al (2012) the highest inter-model agreement is found for the interannual and seasonal variability of the solid freshwater export and the solid freshwater storage, which also agree well with observations. In particular, Wang et al (2017) suggested that the spread on the freshwater export from the Arctic towards the Atlantic might be a result of the different representations of the straits (width, depth and grid spacing) and numerical schemes (e.g., momentum advection and boundary conditions). Although Wang et al (2017) did not attribute a one way response to model resolution, they found that increased horizontal ocean model resolution does not necessarily lead to liquid freshwater fluxes comparable with observations.…”

Fast EVP Solutions in a High‐Resolution Sea Ice Model

“…In this paper we use a mesh with a 4.5‐km horizontal grid spacing (defined as the length of the triangle sides) in the Arctic Ocean and an equivalent of 1° resolution in the rest of the globe (Wang, Wekerle, Danilov, Wang, et al, ). The mesh has 47 unevenly spaced vertical layers.…”

“…Most of the model parameters in our runs are the same as those of Wang, Wekerle, Danilov, Wang, et al (). The transition from FESOM1.4 to FESOM2, however, leads to some modifications in the ocean circulation, which will be reported in a dedicated ocean model evaluation paper.…”

“…The model is run in a global configuration with uniform refinement to 4.5 km in the entire Arctic Ocean. This mesh has been used in FESOM simulations for Arctic Ocean studies (Wang, Wekerle, Danilov, Wang, et al, ; Wang, Wekerle, Danilov, Koldunov, et al, ; Wang et al, ). Its resolution already allows to simulate numerous LKFs in the sea ice field (Wang, Danilov, et al, ).…”