Abstracts

Variability in AOGCM Prediction of Sea Surface Temperature Change on the Scotian and Newfoundland-Labrador Shelf

Gail Chmura¹, Charles Menza
¹McGill University
chmura@geog.mcgill.ca

For two Large Marine Ecosystems on Canada's Atlantic coast (the Scotian Shelf and the Newfoundland-Labrador Shelf) we compare the change in sea surface temperatures projected by output of seven Global Atmosphere-Ocean General Circulation Models (AOGCMs) in two climate change scenarios. Outputs from AOGCMs show a relatively high consistency when considering global average changes, but at the regional scale the models display area-average biases that are highly variable from region to region evident even in our analysis of LMEs, ocean regions designated for large scale fisheries management that have areas greater than 200,000 sq km.

Climate model output indicates changes in seasonality on the Scotian Shelf that could affect coupling of phytoplankton and grazers, thus availability of production to fisheries. Today water temperatures of the Scotian Shelf have exceptionally high seasonal variability. Five of the models project decreased seasonality and all warmer temperatures. Projections of increased winter SSTs on the Scotian Shelf range from 0.5 to 12.1ºC and in summer 1.4 to 10.3ºC higher.

Although waters may warm on the Scotian Shelf, the adjacent northern waters may cool, preventing the northward shift of species, compressing the range of some. Six models project increased SSTs in the summer and winter for the Newfoundland-Labrador Shelf, but the US NCAR model projects lower SSTs there. Projections of SST differences range from -0.1 to 9.8ºC in winter and -5.7 to 9.3ºC in summer.

2005-04-05