Drag coefficient reduction at very high wind speeds

Abstract

The correct representation of the 10-m drag coefficient for momentum (K10) at extreme wind speeds is very important for modeling the development of tropical depressions and may also be relevant to the understanding of other intense marine meteorological phenomena. We present a unified boundary layer model for (K10), which takes account of both the wave field and spray production, and asymptotes to the growing wind wave state in the absence of spray. The theoretical development is based on an air-sea system with shear layers in both fluids and contains three constants that must be determined empirically. This is done using data from observations, and the resulting behavior is interpreted in t..