Details of stratification in a sloping bottom boundary layer of Great Meteor Seamount

Abstract

Detailed temperature and current observations show rapid variations in vertical overturning and stratification above Great Meteor Seamount. Classically, steady downwelling interior flow generates a large homogeneous turbulent bottom boundary layer (bbl) and upwelling interior flow generates a small bbl above a sloping bottom. In contrast, the present observations show the dominance of bores and waves in bbl variations above a slope that is non‐critical for internal tidal waves. During the upslope tidal phase a small bbl is preceded by a breaking bore extending up to 50 m. The bore shows many small stratified layers. These small layers organize in two large, strongly stratified layers, one at <10 m, the other at ∼40 m. During the downslope phase only the lower remains. Above it a thick ∼homogeneous layer is observed, which however does not reach the bottom and thus cannot qualify as a bbl having no influence on sediment resuspension.