The effects of driver data on the performance of the FinROSE chemistry transport model

Abstract

In this paper we tested the performance of the FinROSE chemistry transport model for three different datasets from the European Centre for Medium-Range Weather Forecasts (ECMWF). Global middle atmospheric simulations from 1990 to 2005 were done using winds and temperatures from the ECMWF re-analysis (ERA) datasets, the ERA-40, the operational and the ERA-Interim. Analysis data was used in all simulations. The performance of the model for each dataset was analysed using the simulated stratospheric age-of-air and the ascent rate in the tropics. The ERA-40 data produced with a three-dimensional variational assimilation system (3D-Var) resulted in a too strong Brewer–Dobson circulation. The operational analysis produced with a four-dimensional variational assimilation system (4D-Var) gave somewhat improved results, and the new 4D-Var ERA-Interim re-analysis resulted in a much more realistic upward transport. Also the modelled ozone showed better agreement with observations when using the new re-analysis data.

Acknowledgements

We thank ECMWF for re-analysis datasets and D. Dee and R. Dragani at ECMWF for valuable comments on the ERA-Interim data. We also want to thank the Ozone Processing Team at the NASA Goddard Space Flight Center for the TOMS data, the OMI groups for the OMI column ozone data, the Bremen group for the GOME and SCIAMACHY data and the UARS reference atmosphere project for the water vapour data. Funding from the Academy of Finland through the FARPOCC project and the Vilho, Yrjö ja Kalle Väisälä foundation is gratefully acknowledged.