Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 7 3 2007 10.5194/acp-7-599-2007 http://www.atmos-chem-phys.net/7/599/2007/ http://www.atmos-chem-phys.net/7/599/2007/acp-7-599-2007.html http://www.atmos-chem-phys.net/7/599/2007/acp-7-599-2007.pdf 599 608 2007-02-07 Differences between the QBO in the first and in the second half of the ERA-40 reanalysis H. J. Punge heinzjuergen.punge@zmaw.de M. A. Giorgetta Max Planck Institute for Meteorology, Bundesstr. 53, 20146 Hamburg, Germany IMPRS on Earth System Modelling, Bundesstr. 53, 20146 Hamburg, Germany The representation of the quasi-biennial oscillation (QBO) is investigated in the ERA-40 reanalysis. In the lower stratosphere, where there are a reasonable number of observations, the representation of the QBO is equally good throughout the record. 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