Comparison of hydrography and circulation on the Newfoundland Shelf during Pages 1990-1993 with the long-term mean

Meteorological and ice data from the Atlantic region indicate that the large-scale atmospheric circulation over the Northwest Atlantic during the early 1990s caused below-normal air temperatures in eastern Canada, resulting in increased ice growth during winter, increased ice transport from northern latitudes, and increased freshwater from melting ice during spring. The reduced solar flux onto the ocean surface resulted in a 3-to 4-wk delay in the annual warming cycle causing record low temperatures over the upper water column throughout the Newfoundland Shelf region. We examined temperature, salinity, and current measurements from acoustic Doppler current profilers, moored current meters, and drogued drifting buoys to establish the hydrographic conditions and circulation on the Newfoundland Shelf during 1990-1993 in relation to the longer term (1950-1989) mean. The mean circulation and transport do not show significant departures from the long-term average, but the total advective summer heat transport through the Bonavista transect indicates a 26% reduction during the early 1990s.