Winter surface salinity in the northeastern Gulf of Maine from five years of SMAP satellite data

Wintertime freshwater transport into the Gulf of Maine (GoM) is typically controlled by a seasonal velocity increase in fresh upstream Nova Scotia Current (NSC). Repeat satellite observations from Soil Moisture Active Passive mission have mapped significant GoM surface salinity anomalies four five recent winters. These data are used combination with Jordan basin buoy and model datasets to investigate likelihood that variable wind-forcing NSC contributed these anomalies. This stems regional ocean circulation studies suggesting strengthening alongshore southwesterly winds on Scotian shelf weakens GoM, while cross-shore southeasterly may also contribute weakening, vice versa. A 17-year time series analysis shows near-surface eastern can indeed be modulated both through their impact NSC. The geostrophic current modulation correlates buoy-observed when using one month advective lead time. For shorter 5-year period, SMAP-derived anomaly index indicates similar relation variation Shelf wind relationships between winter variability confirmed output 19-year high resolution global simulation. Attribution local basin-scale atmospheric patterns most years strong freshening coincide weakening North Atlantic Oscillation-like pattern. But its reversals do not always correspond saline GoM. contrast suggests forcing more directly controls but salty. Instead, they partly due density-driven advection neighboring warm slope water including episodic Stream instabilities.