Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 31, 755-764, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
Regular paper
25 Apr 2013
A 20-day period standing oscillation in the northern winter stratosphere
K. Hocke1,2, S. Studer1,2, O. Martius2, D. Scheiben1, and N. Kämpfer1,2 1Institute of Applied Physics, University of Bern, Bern, Switzerland
2Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
Abstract. Observations of the ozone profile by a ground-based microwave radiometer in Switzerland indicate a dominant 20-day oscillation in stratospheric ozone, possibly related to oscillations of the polar vortex edge during winter. For further understanding of the nature of the 20-day oscillation, the ozone data set of ERA Interim meteorological reanalysis is analyzed at the latitude belt of 47.5° N and in the time from 1979 to 2010. Spectral analysis of ozone time series at 7 hPa indicates that the 20-day oscillation is maximal at two locations: 7.5° E, 47.5° N and 60° E, 47.5° N. Composites of the stream function are derived for different phases of the 20-day oscillation of stratospheric ozone at 7 hPa in the Northern Hemisphere. The streamline at Ψ = −2 × 107 m2 s−1 is in the vicinity of the polar vortex edge. The other streamline at Ψ = 4 × 107 m2 s1 surrounds the Aleutian anticyclone and goes to the subtropics. The composites show 20-day period standing oscillations at the polar vortex edge and in the subtropics above Northern Africa, India, and China. The 20-day period standing oscillation above Aral Sea and India is correlated to the strength of the Aleutian anticyclone.

Citation: Hocke, K., Studer, S., Martius, O., Scheiben, D., and Kämpfer, N.: A 20-day period standing oscillation in the northern winter stratosphere, Ann. Geophys., 31, 755-764, doi:10.5194/angeo-31-755-2013, 2013.
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