Change of Regime of Air-Sea Dynamics in Extreme Metocean Conditions

Abstract

As a reference point for the extreme Metocean conditions, the hurricane-scale classification is often used: that is a tropical storm becomes a hurricane if the wind speed reaches U ∼ 33m/s. In this paper, it is argued that such classification is not arbitrary, and indeed signifies change of the physical regimes in all environments near the air-sea interface: in the atmospheric boundary layer, at the surface, and through the upper ocean. This threshold is approximately the wind speed at which the drag coefficient was found to saturate in the field observations (U10 ≈ 32–33m/s), which saturation has received a lot of attention. Less known are the observations that below the surface, change of ..