climate.uvic.ca

Project # : S02-13-01

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

2. PRINCIPAL INVESTIGATOR(S) : A. J. Weaver

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

4. REPORT AGAINST PROJECT GOALS AND DELIVERABLES (for period ending September 30, 2002) :

The primary objective of this work is to investigate the effects of Arctic Ocean related processes and their parametrisations in a global climate model upon increasing atmospheric CO2 concentrations. To address this objective, a first step was to obtain a series of steady state simulations of the preindustrial climate. This has been achieved using the Earth System Climate Model, developed in the Climate Modelling Group of the University of Victoria.

The simulated preindustrial climates differ in several important ways. These include:

Starting from these steady states with fixed levels of atmospheric CO2, a series of transient climate change simulations have been performed by gradually increasing the CO2 concentration at a rate of 1% per year. The CO2 level was allowed to reach four times the initial value by the 140th year and remained unchanged thereafter.

A preliminary analysis of these numerical experiments indicates the importance of initial position of sea ice edge in the Northern North Atlantic for simulating the transient response of the rate of North Atlantic Deep Water (NADW) formation to the increasing CO2 concentration. This is illustrated in Figure 1, which shows the response of maximum meridional overturning in the North Atlantic relative to its steady state value in each climate change simulation (a) and the associated response of sea ice area in the Northern North Atlantic (b). We found that the further north the position of sea ice edge in the unperturbed climate state, the larger the initial reduction of the rate of deep water formation in the North Atlantic in the response to increasing CO2.

5. ANY COMMENTS OR CONCERNS ON STATE OF PROGRESS : None

6. CCAF FUNDS RECEIVED, APRIL 1 TO SEPTEMBER 30, 2002 : $ 30,000.00

7. CCAF FUNDS SPENT, APRIL 1 TO SEPTEMBER 30, 2002: $ 25,082.59

8. PREPARED BY: A. J. Weaver

9. DATE: November 1st , 2002


UVic / SEOS / Climate Group / Research Funding / CCAF Weaver, Saenko, Eby Last updated: Monday, 30-Sep-2002 09:44:54 PDT