Objective assessment of ozone in chemistry-climate model simulations

• Main Authors: Karpechko, Alexey Yu., Gillett, Nathan P., Hassler, Birgit, Rosenlof, Karen H., Rozanov, Eugene
• Format: Report
• Language: English
• Published: Copernicus 2009
• Subjects: Antarctic; The Antarctic; Antarc*
• Online Access: https://hdl.handle.net/20.500.11850/157207; https://doi.org/10.3929/ethz-b-000157207

Stratospheric ozone recovery is expected to drive pronounced trends in atmospherictemperature and circulation from the stratosphere to the troposphere in the 21st cen-tury, but coupled chemistry-climate models (CCMs) vary widely in their predictions offuture ozone evolution. In order to assess which models might be expected to better simulate future ozone evaluation, we assess the ability of twelve CCMs to simulateobserved ozone climatology and trends and rank the models according to their errorsaveraged across the individual diagnostics chosen. According to our analysis no onemodel performs better than the others in all the diagnostics; however, combining errorsin individual diagnostics into one metric of model performance allows us to objectively rank the models. The multi-model average shows better overall agreement with theobservations than any individual model. Based on this analysis we conclude that themulti-model average ozone projection presents the best estimate of future ozone evolu-tion. Our results also demonstrate a sensitivity of the analysis to the choice of referencedata set for vertical ozone distribution over the Antarctic, highlighting the constraints that large observational uncertainty imposes on such model verification. ISSN:1680-7375 ISSN:1680-7367