We present a detailed discussion of the chemical and dynamical processes in the Arctic winters 1996/1997 and 2010/2011 with high resolution chemical transport model (CTM) simulations and space-based observations. In the Arctic winter 2010/2011, the lower stratospheric minimum temperatures were below 195 K for a record period of time, from December to mid-April, and a strong and stable vortex was present during that period. Simulations with the Mimosa-Chim CTM show that the chemical ozone loss started in early January and progressed slowly to 1 ppmv (parts per million by volume) by late February. The loss intensified by early March and reached a record maximum of ∼2.4 ppmv in the late March-early April period over a broad altitude range of 450-550 K. This coincides with elevated ozone loss rates of 2-4 ppbv sh -1 (parts per billion by volume/sunlit hour) and a contribution of about 30-55% and 30-35% from the ClO-ClO and ClO-BrO cycles, respectively, in late February and March. In addition, a contribution of 30-50% from the HO x cycle is also estimated in April. We also estimate a loss of about 0.7-1.2 ppmv contributed (75%) by the NO x cycle at 550-700 K. The ozone loss estimated in the partial column range of 350-550 K exhibits a record value of ∼148 DU (Dobson Unit). This is the largest ozone loss ever estimated in the Arctic and is consistent with the remarkable chlorine activation and strong denitrification (40-50%) during the winter, as the modeled ClO shows ∼1.8 ppbv in early January and ∼1 ppbv in March at 450-550 K. These model results are in excellent agreement with those found from the Aura Microwave Limb Sounder observations. Our analyses also show that the ozone loss in 2010/2011 is close to that found in some Antarctic winters, for the first time in the observed history. Though the winter 1996/1997 was also very cold in March-April, the temperatures were higher in December-February, and, therefore, chlorine activation was moderate and ozone loss was average with about 1.2 ppmv at 475-550 K or 42 DU at 350-550 K, as diagnosed from the model simulations and measurements. © 2012 Author(s).
CITATION STYLE
Kuttippurath, J., Godin-Beekmann, S., Lefevre, F., Nikulin, G., Santee, M. L., & Froidevaux, L. (2012). Record-breaking ozone loss in the Arctic winter 2010/2011: Comparison with 1996/1997. Atmospheric Chemistry and Physics, 12(15), 7073–7085. https://doi.org/10.5194/acp-12-7073-2012
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