A High Resolution Coupled Ocean-atmosphere Simulation of the Regional Climate Over Central America
Abstract This study analyzes a relatively high resolution (15km grid spacing), regional coupled ocean-atmosphere simulation configured over Central America. The simulation is forced with global atmospheric and oceanic reanalysis for a period of 25 years (1986-2010). The spatial resolution and the time period of the Regional Climate Model (RCM) simulation are both unprecedented for the region. The highlights of the RCM simulation include the verifiable seasonal cycle of mesoscale features like the low level jets, the mid-summer drought and the seasonal tropical cyclone activity both in the Pacific and in the Atlantic Oceans. Similarly, the seasonal cycle of the robust surface ocean currents in the eastern Pacific and the Costa Rica Dome is also well captured in the RCM simulation. The RCM simulation also resolves the seasonal cycle of the Panama-Colombia Gyre, the Gulf of Papagayo and the Gulf of Tehuantepec Gyre. In many instances we find the RCM improves upon the global reanalysis forcing the simulation, indicating the potential value of dynamic downscaling. Furthermore, the co-evolving components of the atmosphere and ocean in the RCM is an added benefit to the atmosphere only and ocean only global reanalysis forcing the simulation. However, the model displays significant biases that manifest in precipitation, precipitable water, SST and winds which could potentially be improved.