Research Document - 2011/089

An assessment of the physical oceanographic environment on the Newfoundland and Labrador Shelf during 2010

By E. Colbourne, J. Craig, C. Fitzpatrick, D. Senciall, P. Stead, and W. Bailey

Abstract

The North Atlantic Oscillation (NAO) index, a key indicator of climate conditions in the Northwest Atlantic, was at a record low in 2010 and as a consequence, outflow of arctic air masses to the Northwest Atlantic was much weaker than normal. This resulted in a broad-scale warming throughout the Northwest Atlantic from West Greenland to Baffin Island to Newfoundland relative to 2009. Air temperatures were above normal by 2-3 standard deviations (SD) and at a record high at some northern sites on Baffin Island and the Labrador Coast. Sea-ice extent and duration on the Newfoundland and Labrador Shelf decreased in 2010 for the 15th consecutive year, with the annual average reaching a record low. As a result of these and other factors, local water temperatures on the Newfoundland and Labrador Shelf increased compared to 2009 and were above normal in most areas. Salinities on the NL Shelf were lower than normal throughout most of the 1990s, increased to above normal during most of the past decade but decreased to fresher-than-normal conditions in many areas in 2010. At Station 27 off St. John’s, the annual depth-averaged water temperature increased to 2 SD above normal, the second highest on record. Annual surface and bottom temperatures at Station 27 were also above normal by 0.6°C (1 SD) and 0.64 °C (1.7 SD) respectively. Bottom temperatures at Station 27 were slightly below normal in 2009. The area of the Cold-Intermediate-Layer (CIL) water mass with temperatures <0 °C on the eastern Newfoundland Shelf during 2010 was below normal by 0.6 SD off Bonavista and 1 SD off Seal Island Labrador. Average temperatures conditions along sections off eastern Newfoundland and southern Labrador were above normal while salinities were generally below normal. Spring bottom temperatures in NAFO Divs. 3Ps and 3LNO during 2010 were above normal by up to 1 SD and as a result the area of the bottom habitat covered by water <0 °C was significantly below normal. During the fall, bottom temperatures in 2J were at record high values, almost 2 SD above normal and in Divisions 3K and 3LNO they were >1 SD above normal. The volume of CIL water on the NL shelf during the fall was below normal (3^rd lowest since 1980) for the 16^th consecutive year. A composite climate index derived from 26 meteorological, ice and ocean temperature and salinity time series show a peak in 2006, a declining trend in 2007-09 and a sharp increase in 2010 to the 2nd highest in 61 years, indicating warmer than normal conditions throughout the area.

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