Upper slope jets inshore of the Charleston Bump – barriers to shelf-slope exchange?

A field program conducted in winter 2012 just inshore of the seaward deflection of the Gulf Stream at the Charleston Bump observed several week-long periods of strong equatorward along-shelf flow and elevated bottom temperatures over the upper slope and outer shelf. In sea surface temperature imagery these features resemble and appear linked to warm filaments, a known feature associated with meanders of the Gulf Stream as it traverses the southeast coast of North America. However, the character of these upper slope features is not consistent with previous observations of filaments. We here document the characteristics of the jets and suggest that these may be a form of coastal trapped wave, excited on the deep water side of the slope by meanders when the Gulf Stream position is sufficiently far offshore of the shelfbreak. When present, the jets spread onto the outer shelf, creating cross-shelf convergence between the mid- and outer shelf, possibly explaining the presence of persistent mid-shelf maxima in satellite-derived chlorophyll concentration imagery during the winter season.