Projections of ocean properties along the Washington coast: 20–30 years from now

The objective of this study is to evaluate medium-term responses of the coastal waters of Washington state to forcing perturbations associated with climate change. Our research has proceeded along two lines: (1) direct analysis of the output for the region from global climate model simulations presented in IPCC AR4, and (2) dynamical downscaling using a sub-set of the climate models to drive a regional ocean circulation model. The ocean model used is the Regional Ocean Modeling System (ROMS), with 3-km horizontal resolution and 60 vertical layers. Output from the global climate models provides the initial and lateral boundary conditions as well as surface forcing variables for ROMS. The ROMS output is being examined for assessment of upper ocean properties pertaining to marine ecosystem response. Results to date suggest potentially significant changes in summer stratification, surface eddy kinetic energy, and meridional mass transport into the region in years 2030-2040 relative to years 2001-2011. The implications of these changes for the health of the regional marine ecosystem will be discussed.