Gulf of Mine Coastal Current explained

http://web.mit.edu/seagrant/rt06/Pettigrew.pdf

THE RESPONSE OF THE GULF OF MAINE COASTAL CURRENT SYSTEM TO LATE-SPRINGNORTHEASTERLY WIND FORCINGNeal R Pettigrew and Huijie Xue

Seasonal Variations and Driving Factors of the Eastern Maine Coastal Current 

Drifter Observations of the Gulf of Maine Coastal Current

https://coastalscience.noaa.gov/data_reports/drifter-observations-of-the-gulf-of-maine-coastal-current/

 Results indicate that the Gulf of Maine Coastal Current is a strong and persistent feature centered on the 94±23 m isobath, but that particles: (a) deviate from the seasonal-mean core fairly regularly, and are often re-entrained; (b) follow a slower (9 cm/s), less-constrained path in the western portion off the coast of Maine relative to the eastern (16 cm/s) section; and (c) can be affected by wind events and small-scale baroclinic structures. Residence times calculated for each 1/2° grid cell throughout the GoM depict some regions (Eastern Maine and Western Nova Scotia) as being relatively steady, flow-through systems, while others (Penobscot, Great South Channel) have more variable, branching pathways. Travel times for drifters that are retained within the coastal current along the entire western side of the Gulf of Maine are typically less than two months (55 days).

Our model shows that the Eastern Maine Coastal Current (EMCC) possesses two cores, an offshore and a nearshore core that peak in summer and spring, respectively. The two cores can be traced back to outflows from the Bay of Fundy from opposite sides of Grand Manan Island, and both cores are deeper and slightly more onshore in summer and fall in response to tidal mixing, surface thermal stratification and wind. The two cores merge south of Pleasant Bay, then split into two branches again east of Mount Desert Rock, where the nearshore branch flows along the coast, while the offshore branch turns southward to recirculate in the eastern GoME. Subject to variations of Scotian Shelf Water and Slope Water (SW) inflows, the offshore veering occurs further upstream (northeastward) in late winter and summer, but gradually shifts downstream (southwestward) from summer to winter

Seasonal Variations and Driving Factors of the Eastern Maine Coastal Current

Plain Language Summary

The coastal current in the Gulf of Maine (GoME) plays an important role in modulating fisheries in Maine. To investigate the coastal current and its relation to different forcing, a high-resolution circulation model was developed and validated. Our model shows that in the eastern GoME, the coastal current has two cores, namely an offshore and a nearshore core peaking in summer and spring, respectively. The two cores can be traced back to outflows from the adjacent Bay of Fundy. Both cores are deeper and slightly more onshore in summer and fall due to tidal mixing, large solar radiation and weak wind. The two cores merge as they flow downstream, then bifurcate again east of Mount Desert Rock, where the nearshore branch flows along the coast, while the offshore one turns southward. Subject to variations of inflows from outside of the gulf, the offshore turning occurs further upstream in late winter and summer, but gradually shifts downstream from summer to winter. Analyses of momentum balance show that the coastal current is primarily modulated by the variation of deep denser water inflow that is blended by tidal mixing.

===================

Drifter observations of the Gulf of Maine Coastal Current