A fully coupled atmosphere–ocean wave modeling system for the Mediterranean Sea: interactions and sensitivity to the resolved scales and mechanisms

• Published in: Geoscientific Model Development Vol. 9; no. 1; pp. 161 - 173
• Main Authors: Katsafados, P, Papadopoulos, A, Korres, G, Varlas, G
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 21-01-2016; Copernicus Publications
• Subjects: Aerodynamic drag; Air-sea flux; Air-sea interaction; Analysis; Atmosphere; Atmospheric models; Case studies; Climatology; Computer applications; Computer simulation; Crosstalk; Data exchange; Drag; Drag coefficient; Drag coefficients; Energy; Experiments; Fluxes; Friction; High resolution; Hurricanes; Interactions; Mathematical analysis; Modelling; Momentum; Momentum flux; Momentum transfer; Numerical prediction; Ocean circulation; Ocean models; Ocean surface; Ocean waves; Ocean-atmosphere interaction; Oceans; Parameterization; Partial differential equations; Sea state; Sea states; Sea surface; Sediment transport; Significant wave height; Significant waves; Software; Surface chemistry; Talking; Temperature (air-sea); Velocity; Water waves; Wave height; Wave spectra; Weather; Weather forecasting; Wind; Wind speed; Wind waves; Winds; Mediterranean Sea
• ISSN: 1991-9603; 1991-959X; 1991-962X; 1991-9603; 1991-962X
• DOI: 10.5194/gmd-9-161-2016

It is commonly accepted that there is a need for a better understanding of the factors that contribute to air–sea interactions and their feedbacks. In this context it is important to develop advanced numerical prediction systems that treat the atmosphere and the ocean as a unified system. The realistic description and understanding of the exchange processes near the ocean surface requires knowledge of the sea state and its evolution. This can be achieved by considering the sea surface and the atmosphere as a continuously cross-talking dynamic system. Following and adapting concepts already developed and implemented in large-scale numerical weather models and in hurricane simulations, this study aims to present the effort towards developing a new, high-resolution, two-way fully coupled atmosphere–ocean wave model in order to support both operational and research activities. A specific issue that is emphasized is the determination and parameterization of the air–sea momentum fluxes in conditions of extremely high and time-varying winds. Software considerations, data exchange as well as computational and scientific performance of the coupled system, the so-called WEW (worketa-wam), are also discussed. In a case study of a high-impact weather and sea-state event, the wind–wave parameterization scheme reduces the resulted wind speed and the significant wave height as a response to the increased aerodynamic drag over rough sea surfaces. Overall, WEW offers a more realistic representation of the momentum exchanges in the ocean wind–wave system and includes the effects of the resolved wave spectrum on the drag coefficient and its feedback on the momentum flux.