| Summary: | To improve our understanding of the Arctic marine ecosystem variations in response to climate changes, this project developed the high-resolution Regional Arctic System Model (RASM) with an addition capacity of coupled sea ice and marine biogeochemistry (mBGC). During the course of the project, we published nine journal papers, and one still under review. Our main outcomes are: 1) built up the coupled ice-ocean mBGC codes into the RASM; 2) evaluated the model extensively in the subarctic and Arctic Oceans with multidecadal observational data. The global coarse resolution model and high resolution regional model converge to similar mean status of observed physical ecosystem environments in general, but high resolution model can better represent areas with sharp topographic gradient, and shelf-basin exchanges, thus get reduced model errors compared with observations; 3) compared with other arctic ecosystem models with different model domains, resolutions and parameters to better understand model behaviors. Our models performed reasonably well in simulation of spatial distribution of annual cycle of ocean stratification, nutrients, chlorophyll and primary production etc. compared to other models; 4) investigate arctic marine ecosystem changes in response to climate changes. Under a warming arctic with declining sea ice cover, the total primary production within the Arctic Circle is increasing according to our model, in agreement with several other models and remote sensing results. 5) released the RASM version 1 to general public and conducted education and outreach through various presentations at scientific conferences and to non-professional audiences. The archived data are the high resolution Regional Arctic System Model (RASM) and ecosystem model code and input parameters, the model can be run as a G-case (ice-ocean-ecosystem with atmospheric reanalysis forcing data, e.g., National Center for Atmospheric Research Coordinated Ocean-ice Reference Experiments II (NCAR CORE II) data from 1948-2009, or Japan's Japanese 55-year Reanalysis (JRA) 55 data from 1958 to near present) or fully coupled case (atmosphere-land-ice-ocean-ecosystem). The model domain is pan-arctic region (north of 30 degree north) with around 9 kilometer model grid.
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