Fronts, stratification, and mixing in Long Island and Block Island sounds

Abstract

Spatial patterns of bulk stratification in Long Island and western Block Island sounds observed near the fall equinox of 1978 show a strong correlation (r = 0.79) with contours of the h/U3 stratification index derived from tidal stream and depth charts. The index delineates stratified, transitional, and mixed regions with apparent good accuracy, with the marginally stratified frontal zones being characterized by log10 h/U3 ∼ 1.5 m−2 s3. These results and theoretical considerations suggest that the index may be a useful parameter in corroborating and predicting frontal boundaries in other moderately stratified estuaries where local buoyancy fluxes are derived from fresh water sources.