Use of ROMS to downscale ocean climate scenarios - South Atlantic case

IPCC model projections for the late 21st century show temperature increases and circulation changes in the Southwestern Atlantic, which will impact regional ocean dynamics and local weather systems. We are using ROMS as a numerical downscaling tool to improve time-space climate scales. This poster focuses on the model general behavior, boundary conditions, long term stability, and capability to reproduce climate regional dynamics.

The hydrodynamic model validation was based on its ability to reproduce general (but local) known phenomena. For that, we are using 20th century ocean reanalysis (SODA) and other measured data sets. These comparisons show good agreement between model and data and also between the different model runs. The partial conclusion here points to a high level of accuracy and model stability in long term runs. The model standard boundary formulations (low frequencies and baroclinic flows) work well for this kind of simulation. This has allowed us to start downscaling experiments from GCM (RCPs). These new GCM results, specially cloud cover and precipitation rates, are expected to contribute to and increase the results accuracy and the model predictability skill. Future runoff sensitivity experiments, specifically near the Amazon and Prata river mouths, will use this specific South Atlantic configuration (SAC).

(Pereira, J.E.R.-IOUSP; Wainer, I.-IOUSP)