Quantification of the Spatial Variability of the Ocean Surface Roughness and Momentum Flux
Abstract
It is well known that physical processes occurring at the air-sea interface, such as air-sea mass, momentum, and energy exchanges, are controlled by the ocean surface roughness that has often been characterized in the literature as being homogeneous in space and time from a large-scale point of view. However, the ocean surface roughness is heterogeneous within a wavelength. The surface areas on wave crests are usually rougher than those on wave troughs. The mechanisms range from capillary ripples on wave crests to larger scale wave breaking. Ambient swell and non-uniform currents also can cause significant spatial variations of the surface roughness as short waves become steeper on the swell crest than those on the swell trough. This study parameterizes the spatial variability of the sea surface roughness and quantifies the resultant variations of momentum and energy exchanges between the atmosphere and the coastal ocean using a phase-resolving numerical wave model. Numerical experiments were carried out to test a hypothesis for the suppression of the wave growth rate by the following swell. A simple mechanism is suggested to explain the influence of swell on the short waves observed in the numerical and laboratory experiments.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2004
- Accession Number
- ADA430399
Entities
People
- Qin J. Chen
Organizations
- University of South Alabama