On the influence of location of high-latitude ocean deep convection and Antarctic sea-ice on climate change projections

• Published in: Journal of Climate
• Main Authors: Schaeffer, M., Selten, F., Goosse, Hugues, Opsteegh, T.
• Other Authors: UCL - SST/ELI/ELIC - Earth & Climate
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Meteorological Society 2004
• Subjects: CISM: CECI; 1443; Antarctic; Norway; Antarc*; North Atlantic; Sea ice
• Online Access: http://hdl.handle.net/2078.1/129620; https://doi.org/10.1175/3174.1

The mean state and variability of deep convection in the ocean influence the North Atlantic climate. Using an ensemble experiment with a coupled atmosphere–ocean–sea ice model, it is shown that cooling and subdued warming areas can occur over the North Atlantic Ocean and adjacent landmasses under global warming. Different ‘‘present-day’’ convection patterns in the Greenland–Iceland–Norway (GIN) Sea result in different future surface- air temperature changes. At higher latitudes, the more effective positive sea ice feedback increases the likelihood of changes in convection causing a regional cooling that is larger than the warming brought about by the enhanced greenhouse effect. The modeled freshening of deep ocean layers in the North Atlantic in a time period preceding a reorganization of GIN Sea convection is consistent with recent observations. Low-frequency internal variability in the ocean model has relatively little impact on the response patterns.