Arctic cubed sphere configuration of MITgcm with 2-km resolution

This repository includes a regional Arctic configuration of the Massachusetts Institute of Technology general circulation model (MITgcm,Marshall et al., 1997; MITgcm Group, 2017) with a horizontal resolution of 2 km, which is described in Hutter & Losch (2020). It is based on a regional Arctic configuration (Nguyen et al., 2012) of the MITgcm, which represents the Northern face of a global cubed sphere configuration. The number of vertical layers is reduced to 16, with the first 5 layers covering the uppermost 120 m to decrease the computational cost associated with the ocean model component. The Refined Topography dataset 2 (RTopo-2) (Schaffer and Timmermann, 2016) is used as bathymetry for the entire model domain. The lateral boundary conditions are taken from the globally optimized ECCO-2 simulations (Menemenlis et al., 2008). The configuration is designed to use the 3-hourly Japanese 55-year Reanalysis (JRA-55, Kobayashi et al., 2015) with a spatial resolution of 0.5625° for surface boundary conditions. The ocean temperature and salinity are initialized on 1 January, 1992, from the World Ocean Atlas 2005 (Locarnini et al., 2006; Antonov et al., 2006). The initial conditions for sea ice are taken from the Polar Science Center (Zhang et al., 2003). Ocean and sea ice parameterizations and parameters are directly taken from Nguyen et al. (2011), with the ice strength P=2.264×104Nm−2. The configuration uses the classical discrimination of two ice classes: thin and thick ice (Hibler, 1979). The momentum equations are solved by an iterative method and line successive relaxation (LSR) of the linearized equations following Zhang and Hibler (1997). In each time step (\(\Delta\)t=120 s), 10 nonlinear steps are made and the linear problem is iterated until an accuracy of 10e−5 is reached or 500 iterations are performed.  With this configuration, simulations were run from 1 January 1992 to 31 December 2012. We also provide pickup files to restart the simulation in 2012.

To reference this configuration please use the citation of this repository and reference to the paper describing the configuration:

Hutter, N. and Losch, M.: Feature-based comparison of sea ice deformation in lead-permitting sea ice simulations, The Cryosphere, 14, 93–113, https://doi.org/10.5194/tc-14-93-2020, 2020.