CCAF-Science Quarterly Report for Period Ending 30 December 2003

Project # : S02-13-01

1. PROJECT TITLE : The effect of Arctic Ocean processes on global climate change


3. COLLABORATOR(S ): O. A. Saenko and M. Eby

4. PROGRESS (for 1 October through 30 December 2003):

Progress achieved

  1. The paper entitled “The effect of sea-ice extent in the North Atlantic on stability of the thermohaline circulation in global warming experiments” has just been accepted for publication in Climate dynamics. The original reviews were favourable but the reviewers did ask for minor revisions and that some additional experiments be conducted. Two additional integrations were carried out with increased heat transport in the atmosphere to test the sensitivity of the original results. The experiments show that the overturning response to global warming can be positive, when sea ice is present near areas of deep water formation. Once sea ice is removed from these areas, the response to global warming is a decrease in overturning (much like that seen in flux adjusted experiments).

  1. Results of the final set of experiments involving the separation of thermal and fresh water fluxes due to global warming are still being analyzed and some additional integrations need to be completed. Initial results confirm that sea ice may be one of the major reasons for differences in the thermohaline response in various coupled models. The results of these experiments will form part of the paper in preparation (see below).

Milestones attained

Two papers have been completed and a third is being prepared. Results have shown that the representation of sea ice, especially in areas of deep water formation, can have a major effect on the thermohaline response in coupled models. Climate models show considerable variation in their THC response to global warming. Understanding these differences is necessary to reduce the uncertainty in the models predictions.

Deliverables completed

Papers in preparation, in press, or completed that will be acknowledging CCAF funding are as follows:

Eby M., O. A. Saenko and A. J. Weaver, 2003: Response of the thermohaline Circulation, in a coupled model, to global warming, fresh water forcing,

in preparation:

Saenko O. A., M. Eby and A. J. Weaver, 2003: The effect of sea-ice extent in the North Atlantic on stability of the thermohaline circulation in global experiments, Climate Dynamics, IN PRESS.

Saenko O. A., E. C. Wiebe and A. J. Weaver, 2003: North Atlantic response to the above-normal export of sea ice from the Arctic. J. Geophys. Res., Vol. 108, No C7, 3224, doi:10.1029/2001JC001166.


6. PREPARED BY: A. J. Weaver

7. DATE: February 1, 2003

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