Correlation between Foam-Bubble Size and Drag Coefficient in Hurricane Conditions

TL;DR

This paper investigates how foam-bubble size influences the air-sea drag coefficient during hurricanes, using a model that relates foam coverage and roughness to wind speed to better understand hurricane surface interactions.

Contribution

It introduces a model linking foam-bubble size and drag coefficient, providing a method to estimate foam bubble radius variation with wind speed in hurricane conditions.

Findings

Model relates foam coverage to drag coefficient and roughness length.

Inverse problem approach estimates foam bubble radius from known data.

Enhanced understanding of foam impact on hurricane surface dynamics.

Abstract

Recently proposed model of foam impact on the air sea drag coefficient Cd has been employed for the estimation of the efficient foam-bubble radius Rb variation with wind speed U10 in hurricane conditions. The model relates Cd (U10) with the efficient roughness length Zeff (U10) represented as a sum of aerodynamic roughness lengths of the foam free and foam covered sea surfaces Zw (U10 ), and Zf (U10) weighted with the foam coverage coefficient. This relation is treated for known phenomenological distributions Cd (U10), Zw (U10) at strong wind speeds as an inverse problem for the efficient roughness parameter of foam-covered sea surface Zf (U10).