Surface forcing on the southern flank of Georges Bank, February-August 1995

[1] Surface wind stress, heat, and freshwater fluxes were estimated over the southern flank of Georges Bank during February - August 1995 using moored measurements made at ST1 located on the 76-m isobath, roughly halfway between the tidal mixing and shelf/ slope fronts. Wind stress variability was dominated by a succession of atmospheric lows that passed Georges Bank during the deployment. A transition between frequent lows and strong wind stress events ("winter'') to less frequent lows and weaker wind stresses ("summer'') occurred in mid-May. In winter, wind stress fluctuations tended to be omnidirectional, with maximum stresses above 0.5 N/m(2) during four storms, one a classic "nor'easter'', while summer fluctuations were weaker but strongly polarized in the alongbank direction. The ST1 surface heat flux was dominated by shortwave heating, which increased from a winter mean of 130 W/m(2) to 230 W/m(2) in summer. Long-wave cooling decreased from 50 W/m(2) (winter) to 30 W/m(2) (summer), while mean sensible and latent fluxes increased from - 20 and - 40 W/m(2) (winter) to + 10 and 0 ( summer) respectively. Overall, winter was characterized by weak net heating (30 W/m(2)) with shortwave gain offset by long-wave, latent, and sensible heat loss. In summer, increased shortwave gain and reduced long-wave loss and weak sensible and latent fluxes combined to produce strong net heating (210 W/m(2)). ST1 precipitation was highly episodic with little seasonality while evaporation occurred mostly during winter, resulting in a net evaporation of - 15 cm and net freshwater flux of + 48 cm over the deployment.