Implications of the enhanced Brewer-Dobson circulation in ERA-40 for the downward transport of ozone to the troposphere

As part of the EU project RETRO, whose aim is to reanalyse the tropospheric chemical composition since the late 1950s on the basis of ERA-40, the 45-year meteorological reanalysis that has recently been completed by the ECMWF, this study addresses the question how to simulate the downward transport of stratospheric ozone given that the Brewer-Dobson circulation in ERA-40 has a strong bias.