Abstract
Nowadays, it has become clear that atmosphere and ocean should be simulated by integrated modeling systems resolving interconnected physical factors which determine Earth’s energy balance. Waves play a key role on the interfacial interaction between atmosphere and ocean regulating momentum, heat and moisture exchange. This study aims to evaluate the two-way coupled atmosphere-ocean wave system CHAOS (Chemical Hydrological Atmosphere Ocean wave System) over the Mediterranean and Black Seas. The evaluation is performed against in-situ and remote sensing data for the period from 1 December 2013 to 1 December 2014. CHAOS includes the Weather Research Forecasting (WRF) model version 3.8 as atmospheric component and the Wave model (WAM) cycle 4.5.4 as ocean wave component, coupled through the OASIS3-MCT coupler version 3.0. In order to assess the impact of the atmosphere-ocean waves coupling, two approaches of continuous model simulations are followed. In the first approach (1-way coupling mode) the ocean wave component uses the winds produced by the atmospheric component while in the second approach (2-way coupling mode) the atmospheric component additionally uses the sea state information estimated by the ocean wave component through wave-dependent Charnock parameter computations. In the 2-way coupling mode, the attenuation of the atmospheric flow has a damping effect on wind-generated waves. The simulations in 2-way coupling mode produce more realistic results yielding statistical improvements. Against buoys observations, 2-way reduces root mean square error (RMSE) per 1.2% and 6.3% for wind speed and significant wave height, respectively, while against Jason-2 satellite retrievals per 0.5% and 2.4%, respectively. Additionally, the 2-way outperforms the 1-way coupling mode under intense wind and wave conditions during this one-year period.