Quantifying Arctic ozone loss during the 2004–2005 winter using satellite observations and a chemical transport model

摘要

During the last decade, much attention has been placed on quantifying and modeling Arctic stratospheric O3 loss. At issue in particular is the reliability of models for simulating the loss under variable dynamical conditions in the Arctic region. This paper describes inferred O3 loss calculations for the 2004–2005 Arctic winter using data from four solar occultation satellite instruments, as well as the Earth Observing System Microwave Limb Sounder (EOS MLS). O3 loss is quantified with the “Chemical Transport Model (CTM) passive subtraction” approach, using a passive O3 tracer field from the SLIMCAT CTM. The 2004–2005 Arctic winter was moderately active dynamically, but was still one of the coldest Arctic winters on record, with prime conditions for O3 loss. Loss estimates inferred from all of the different satellite instruments peaked in mid-March at 450 K between 2–2.3 ppmv, slightly less than similar estimations for the cold 1999–2000 winter. The SLIMCAT CTM was also used to simulate O3 for the 2004–2005 winter. In March, near 450 K, the model O3 was 0.3 ppmv (～10–15%) lower than the observations, leading to a maximum O3 loss that was 10–15% larger than that inferred from observations, using the passive subtraction approach. Modeled loss maximized around the same time as that inferred from observations. Although some discrepancies between the observed and modeled O3 remain, the level of agreement presented here shows that the SLIMCAT CTM was able to satisfactorily simulate O3 and polar O3 loss during the dynamically active 2004–2005 Arctic winter.