Wind, waves and Langmuir circulation during CBLAST-Low

As a part of the 2003 Coupled Boundary Layers and Air-Sea Transfer (CBLAST) Low-Wind Experiment, surface winds, surface waves, upper- ocean structure, and Langmuir circulation strength were observed with instrumentation deployed at the Martha's Vineyard Costal Observatory and the CBLAST Air-Sea Interaction Tower (ASIT) about 2 miles south of Martha's Vineyard, Massachusetts. Varying wind directions relative to Martha's Vineyard create a complex wave field which may contain growing, short-fetch wind waves, decaying wind waves, and persistent swell from the south. Data from various sources were used to estimate wave parameters associated with each component. The strength and dominant scale of Langmuir circulation were determined from a surface-scanning ADCP that measured the horizontal structure of velocity near the ocean surface at scales from ~10-100 m. The relationship between observed Langmuir circulation strength and surface forcing is explored, with particular attention to the scaling of circulation strength with wind stress and Stokes drift, and the influence of wave age.