Climate Modelling Group
School of Earth and Ocean Sciences

1. PROJECT TITLE: Analysis of the Variability of the Arctic Oscillation under Enhanced Greenhouse Warming

Project # (for CCAF use)

S99-13-12

2. PRINCIPAL INVESTIGATOR(S):

Daithi A. Stone and Andrew J. Weaver

3. COLLABORATOR(S):

 

4. REPORT AGAINST PROJECT GOALS AND DELIVERABLES (for period ending 31 March 2000):

D. Stone, A Ph.D. student who is supported through CCAF funds, has made substantial progress towards the completion of several of the goals of this project. Preliminary results have been very encouraging and were recently presented at the Climate Variability Workshop, McGill University (27-28 March 2000). To date he has developed a suite of diagnostic routines to calculate the dominant patterns of variability in the sea level pressure (SLP) and surface air temperature (SAT) data sets obtained from the 1x, 2x and 4x CO2 equilibrium simulations of the GFDL coupled model. He has also developed routines to display various aspects of these data and their dominant modes.

One of the goals of this project was to verify the hypothesis that the Arctic Oscillation (AO) and other dominant patterns of variability remain important in climates with higher greenhouse gas concentrations. D. Stone has calculated the dominant modes of variability in both the SLP and SAT data fields using several approaches. The AO was found to dominate the variability of the SLP field in the extratropical Northern Hemisphere. Furthermore, this pattern remains important in climates with higher greenhouse gas concentrations. Similarly, other dominant patterns of variability in SLP remain important in the different climates. On the other hand, the dominant patterns of variability in SAT do not remain important in the different climates, since these modes are related to variations in sea ice extent that changes substantially in warmer climates. However, using an approach that standardises the variance, other modes of SAT variability unrelated to sea ice are found that remain important in the warmer climates.

Another goal of this project was to determine if climate change induced by increased greenhouse gas concentrations projects onto the natural modes of climate variability. Mean changes in the simulated climates induced by higher greenhouse gas concentrations have been projected onto the AO and other patterns of variability. It was found that these changes do not project exclusively onto the AO or any of the other modes.

D. Stone is now proceeding to examine whether changes in climate variability in the warmer climate project onto the AO and other patterns of variability obtained from the present climate, and thus whether the behaviour of these modes changes.

 

5. ANY COMMENTS OR CONCERNS ON STATE OF PROGRESS:

None. This project is progressing on schedule and will be completed by March 31, 2001.

6. CCAF FUNDS RECEIVED

TO MARCH 31, 2000: $13,000

7. CCAF FUNDS SPENT

TO MARCH 31, 2000: $13,000

8. SOURCES AND AMOUNTS OF non-CCAF FUNDS USED TO DATE (CASH AND IN-KIND):

The infrastructure and personnel support for the Climate Modelling Lab, for projects related to this CCAF initiative comes from NSERC ($180,000 in the past year). IARC funds (50K US) were used to free up Weaver's time through salary relief and have provided additional operating support. Collaboration continues with R. Stouffer at GFDL.

9. PREPARED BY:

Andrew Weaver

10. DATE:

April 3, 2000


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