MIZMAS is a coupled ice/ocean modeling and assimilation system. The ocean circulation model is based on the Parallel Ocean Program (POP) developed at Los Alamos National Laboratory (Smith et al., 1992). The POP ocean model is modified by Zhang and Steele (2007) so that open boundary conditions can be specified. This allows MIZMAS to be nested into a global ice/ocean model. The POP ocean model is further modified by Zhang et al. (2010) to incorporate tidal forcing arising from the eight primary constituents.

The sea ice model is a thickness and enthalpy distribution (TED) sea ice model (Thorndike et al., 1975; Hibler, 1980; Zhang and Rothrock, 2001). The TED sea ice model has eight categories each for ice thickness, ice enthalpy, and snow depth. It is adopted from the Pan-arctic Ice/Ocean Modeling and Assimilation System (PIOMAS; Zhang and Rothrock, 2003), with a high-resolution focus on the Chukchi and Beaufort seas (CBS). It is able to assimilate satellite observations of sea ice concentration and sea surface temperature (SST). We are currently working to incorporate multicategory floe size distribution into the TED ice model for simulating marginal ice zone (MIZ) processes.

The MIZMAS model domain covers the Northern Hemisphere north of 39°N. The MIZMAS finite-difference grid is based on a generalized orthogonal curvilinear coordinate system. The “north pole” of the model grid is placed in Alaska. Thus, MIZMAS has its highest horizontal resolution along the Alaskan coast and in the Chukchi, Beaufort, and Bering seas. For the Chukchi and Beaufort seas, the model resolution ranges from an average of ~4 km in the Alaska coastal areas to an average of ~10 km for the whole region. There are 26 ocean grid cells (average ~3 km) across Bering Strait for a good connection between the Pacific Ocean and the Arctic Ocean. To better resolve the mixed layer and the pycnocline, the ocean’s vertical dimension has 40 levels. The MIZMAS configuration is useful for studying seasonal-to-decadal scale changes in sea ice and ocean dynamics in the CBS and the connection to the pan-arctic system in an efficient and effective manner.


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