Research Document - 2004/53
Physical Oceanographic Conditions on the Scotian Shelf and in the Gulf of Maine during 2003
By Petrie, B., Pettipas, R.G., Petrie, W.M., Soukhovtsev, V., Drinkwater, K.F.
A review of physical oceanographic conditions on the Scotian Shelf and in the Gulf of Maine and adjacent offshore areas during 2003 has shown some broad scale changes from previous years. Cool conditions tended to dominate the Scotian Shelf and to a lesser extent the eastern Gulf of Maine in 2003. Mean annual sea-surface temperature at Boothbay Harbor was 2.4°C above normal, the 7th warmest in 98 years. St. Andrews was 0.6°C below normal, ranking 47th in 83 years from warmest to coldest. At Prince 5, 0-90 m, monthly mean temperatures were generally below normal by 0.1 to 0.3°C. Salinities were generally 0-0.6 above normal throughout the year. Halifax sea surface temperature was 1.8°C below normal, making 2003 the 4th coldest in 78 years. At Halifax Station 2, 0-100 m temperature anomalies were 0 to -2°C; salinity was typically 0-0.5 above normal. Sydney Bight, Misaine Bank and Emerald Basin (to 75 m) featured anomalies of -1 to -2°C. At depths greater than 75 m, Emerald Basin temperatures were about 0.5°C above normal. Lurcher Shoals temperature anomalies were varied but slightly above normal for the year. Georges Basin showed an anomaly reversal like Emerald Basin with temperatures about 1°C below normal 0-100m and 0.5°C above normal deeper. Eastern Georges Bank temperature anomalies varied through the year, negative early, positive late with amplitudes less than 1°C. Standard sections in April, July, October and December on the Scotian Shelf support the overall conclusion of temperatures ~2°C below normal, salinities ~0.5 above normal and a more intense and extensive cold intermediate layer on the shelf. Cabot Strait deep-water (200-300 m) temperatures were near normal. The temperatures from the July groundfish survey were exceptional with the outstanding feature being a very broad cold intermediate layer with below normal temperatures. The July surface temperatures were generally 0o-3°C above normal for the survey region except for the Bay of Fundy where below normal temperatures by up to 2°C prevailed. However, at the deeper layers of 50 m, 100 m and at the bottom below normal temperatures of up to 3°C , 2°C and 1°C dominated. Break-up of the strong stratification pattern established in the late 20th and early 21st century continued in 2003. Though overall stratification was slightly above normal for the Scotian Shelf region, there was considerable variability at small spatial scales. The Shelf/Slope front and the Gulf Stream moved in opposite directions in 2003 with the former moving onshore on average by 22 km compared to its position in 2002 and the latter offshore by 32 km.
- Date modified: