Atmos. Chem. Phys. Discuss., 12, 12423-12451, 2012
© Author(s) 2012. This work is distributed
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Implications of all season Arctic sea-ice anomalies on the stratosphere
D. Cai, M. Dameris, H. Garny, and T. Runde
Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany

Abstract. In this study the impact of a substantially reduced Arctic sea-ice cover on the lower and middle stratosphere is investigated. For this purpose two simulations with fixed boundary conditions (the so-called time-slice mode) were performed with a Chemistry-Climate Model. A reference time-slice with boundary conditions representing the year 2000 is compared to a second sensitivity simulation in which the boundary conditions are identical apart from the polar sea-ice cover, which is set to represent the years 2089–2099.

Three features of Arctic air temperature response have been identified which are worth to be discussed in detail. Firstly, tropospheric mean polar temperatures increase up to 7 K during winter. This warming is primarily driven by changes in outgoing long-wave radiation. Secondly, temperatures decrease significantly in the summer stratosphere caused by a decline in outgoing short-wave radiation, accompanied by a characteristic increase of ozone mixing ratios. Thirdly, there are short periods of statistical significant temperature anomalies in the winter stratosphere probably driven by modified planetary wave activity.

Both the internal as well as the inter-annual variability of Arctic sea-ice content is related to Arctic climatic fields like surface air temperature, sea level pressure or precipitation, which are analogue with the variability of the Arctic Oscillation (AO)-index. In this study significant changes in the AO-index are detected in the course of winter. Neutral phases of AO appear more often. As expected, the dominating dynamical response of the stratosphere during winter turned out to be consistent to alterations in the tropospheric AO, although it is not statistically significant most of the time.

Citation: Cai, D., Dameris, M., Garny, H., and Runde, T.: Implications of all season Arctic sea-ice anomalies on the stratosphere, Atmos. Chem. Phys. Discuss., 12, 12423-12451, doi:10.5194/acpd-12-12423-2012, 2012.
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