Svenja Ryan (Woods Hole Oceanographic Institution, USA); W. Gordon Zhang (Woods Hole Oceanographic Institution, USA); Dihya Chaal (Skidaway Institute of Oceanography, USA)

In this project we are studying the connectivity of the circulation on the Northwest Atlantic shelf. The motivation for this project is two-fold: (1) to understand the fate of fresh water entering the shelf region from the Arctic and Greenland Ice Sheet through Davis Strait and its effect on the AMOC, and (2) to improve predictability of ocean properties in the Gulf of Maine/Mid-Atlantic Bight region that is home to one of the most productive ecosystems globally and has recently experienced dramatic swings in temperature and salinity. The project is divided into three work packages, and in this talk, we will present an update on the first work package focused on validation of the SWOT-derived surface geostrophic velocities. Comparisons between the SWOT velocities and two sets of moored data on the Newfoundland and Labrador Shelf, as well as moorings and a regular ship transect in the Mid-Atlantic Bight will be presented. Furthermore, we will present first results from comparisons of SWOT sea surface height data with data from Pressure Inverted Echo Sounders (PIES) deployed at the northern edge of the Gulf Stream for additional validation of SWOT in an eddy-rich region. For this analysis, we will also assess the impact of different spatial filters when deriving geostrophic velocities. In addition, the SWOT velocities and SSH fields are compared to high-resolution SST and chlorophyll products of the region. The goal of this validation work is to determine the processes resolved by SWOT, including the representation of narrow currents such as coastal currents and the shelf break jet, so that we can move forward in the project with confidence that the shelf-basin exchange is accurately resolved by the SWOT data. The goal of this project is to eventually build on these validation results to quantify the shelf-basin exchange along the Northwest Atlantic Shelf and test the hypothesis that this shelf basin exchange has been increasing through time.