Future Projection of the California Current System Using a Downscaled Coupled Bio-physical Model.

The California upwelling system is one of the most extensively studied US coastal regions because of its diverse ecosystem and importance for marine resources. However, low-resolution climate models fail to achieve a realistic representation of the upwelling and other coastal processes, limiting their applicability in certain problems. Deficiencies in the in the physics of the models hence can have dramatic consequences on the biogeochemistry. This is partly due to the high-sensitivity of the biology to the vertical supply of nutrients. To ameliorate this issue, we implemented the NOAA-GFDL biogeochemical model COBALT in the regional ocean model ROMS permitting a seamless representation of the biogeochemistry across scales. The California Current implementation is at 7 km horizontal resolution forced by downscaled model data from the global GFDL ESM2M RCP8.5 future projection. In this presentation, we will describe our approach to a multi-scale bio-geochemical solution, highlight the benefits of the higher resolution coastal model and describe expected changes to the California Current lower trophic level dynamics under a climate change scenario.