Impact of different sea surface roughness on surface gravity waves using a coupled atmosphere-wave model: a case of Hurricane Isaac (2012)

The complicated pattern of the chaotic ocean surface depends strongly on the interaction between wind and waves. An accurate representation of momentum and energy exchange at air-sea interface is very important for ocean modeling and climate studies. The exchange of momentum, heat, and moisture at the air-sea interface considered a fundamental process in the development of mesoscale atmospheric phenomena such as hurricanes and precipitating systems. Since these exchanges take place in the wave boundary layer, one cannot neglect the importance of ocean surface waves in modifying air-sea interaction processes. In this paper, the sensitivity of a regional coupled atmosphere-wave model to sea surface roughness parameterizations is discussed. In order to see the impact of sea spray in modifying the surface gravity waves, we have introduced a sea-spray parameterization in surface layer scheme of the atmospheric model. We have taken the case of Hurricane Isaac, formed in the Gulf of Mexico in 2012 for this study. It is observed that the newly added sea-spray scheme shows a better performance compared with three existing, well-known formulations. Thus, during extreme events, sea spray can play an important role in modifying the wind and wave height.