The atmosphere sees the ocean, with sometimes huge waves, as a much smoother surface, compared to its passage over land where it is slowed down much more, even if obstacles are small compared to the size of ocean waves. A good observer notices right away that waves travel with the wind and consequently do not give much resistance. The details of how much resistance there actually is and its variation with wind speed and parameters defining the wave conditions has been a hot topic for the last 35 years. The correctness of the roughness formulation is a crucial question in the understanding of the air-sea interface. It has major implications in wave modelling, in storm surge modelling and also in modelling of the atmospheric boundary layer above the ocean.... |