Improving the ability of coupled chemistry-climate models to project future changes in polar stratospheric ozone and its influence on surface climate in the polar regions
Zusammenfassung der Projektergebnisse
The importance of stratospheric ozone as a climate active gas has long been recognised. However, including the interactions between climate change and ozone in climate models is computationally very expensive. As a result, the effects of ozone on climate are usually incorporated into climate models by prescribing ozone. Process oriented evaluation and coordinated analysis of science results is performed by the CCM Validation Activity (CCMVal) within the Stratospheric Processes And their Role in Climate (SPARC) programme, one of the core projects of the World Climate Research Programme. There are still large discrepancies apparent for the CCM projections of polar ozone. Furthermore, sensitivity studies e.g. for different climate conditions are not possible with these expensive models. It is therefore necessary to develop alternative, inexpensive methods to complement the studies with CCMs. In this project we developed a fast and inexpensive stratospheric chemistry scheme to describe the seasonal and inter-seasonal evolution of polar stratospheric ozone. The model is named SWIFT (Semi-empirical Weighted Iterative Fit Technique). SWIFT is semi-empirical in that it is trained on satellite-based measurements of the trace gases complicit in the polar ozone depletion chemistry. We have shown that key atmospheric processes can be reproduced with this semi-empirical model of polar stratospheric chemistry. Fit parameters in this model can be derived and compared for observations and chemistry-climate models (CCMs) and therefore act as means of CCM validation. Future application of the semi-empirical model will imbed SWIFT in a state-of-the-art climate model. We will build a fast emulator of the highly complex CCMs using the semi-empirical equations which are trained on real world observations. This approach will provide ensembles of simulations that span the full range of uncertainty required for international policy. In the DFG proposal we intended to conduct our study with the already existing semi-empirical model. However, these equations could not be adapted to non-Antarctic conditions. Therefore, a new and more complex system of equations was developed. In collaboration with our Berlin and Potsdam colleagues, new applications of this semi-empirical scheme were defined. Overall, the new scheme of equations have a wider range of applications than the original approach. The final outcome was therefore very successful and has found great interest and feedback in the international community. During my work on the DFG project, I have been interviewed twice by national and local TV stations to comment on the status of the ozone hole. • September 2009 : TV3 News • December 2010 : Canterbury TV News
Projektbezogene Publikationen (Auswahl)
- ”Reducing uncertainty in projections of Antarctic ozone through the 21st century using IPY measurements”. Annual Antarctic Conference, Auckland, New Zealand, July 2009
P. E. Huck, G. E. Bodeker, S. Kremser, G. Zeng, and H. Struthers
- ”SWIFT - A new fast semi-empirical model for polar ozone loss”. CCMVal Workshop, Toronto, Canada, June 2009
Rex, Markus; Huck, Petra E.; Kremser, Stefanie; Bodeker, Greg E.; Santee, Michelle L.; Bernath, Peter
- SPARC CCMVal (2010), SPARC Report on the Evaluation of Chemistry-Climate Models, V. Eyring, T. G. Shepherd, D. W. Waugh (Eds.), SPARC Report No. 5, WCRP-132, WMO/TD-No.1526
Petra Huck
- WMO (World Meteorological Organization), Scientific Assessment of Ozone Depletion: 2010, Global Ozone Research and Monitoring ProjectReport No. 52, Geneva, Switzerland, 2011
Petra Huck
