Dee_et_al-2011-Quarterly_Journal_of_the_Royal_Meteorological_Society.pdf

Quarterly Journal of the Royal Meteorological Society Q. J. R. Meteorol. Soc. 137: 553–597, April 2011 A The ERA-Interim reanalysis: configuration and performance of the data assimilation system D. P. Deea*, S. M. Uppalaa, A. J. Simmonsa, P. Berrisforda, P. Polia, S. Kobayashib, U. Andraec, M. A. Balmasedaa, G. Balsamoa, P. Bauera, P. Bechtolda, A. C. M. Beljaarsa, L. van de Bergd, J. Bidlota, N. Bormanna, C. Delsola, R. Dragania, M. Fuentesa, A. J. Geera, L. Haimbergere, S. B. Healya, H. Hersbacha, E. V. Ho?lma, L. Isaksena, P. Ka?llbergc, M. Ko?hlera, M. Matricardia, A. P. McNallya, B. M. Monge-Sanzf, J.-J. Morcrettea, B.-K. Parkg, C. Peubeya, P. de Rosnaya, C. Tavolatoe, J.-N. The?pauta and F. Vitarta a European Centre for Medium-Range Weather Forecasts, Reading, UK b Japan Meteorological Agency, Tokyo, Japan c Swedish Meteorological and Hydrological Institute, Norrko?ping, Sweden d European Organisation for the Exploitation of Meteorological Satellites, Darmstadt, Germany e Department of Meteorology and Geophysics, University of Vienna, Austria f School of Earth and Environment, University of Leeds, UK g Korea Meteorological Administration, Seoul, Korea *Correspondence to: D. P. Dee, ECMWF, Shinfield Park, Reading RG2 9AX, UK. E-mail: dick.dee@ ERA-Interim is the latest global atmospheric reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). The ERA-Interim project was conducted in part to prepare for a new atmospheric reanalysis to replace ERA-40, which will extend back to the early part of the twentieth century. This article describes the forecast model, data assimilation method, and input datasets used to produce ERA-Interim, and discusses the performance of the system. Special emphasis is placed on various difficulties encountered in the production of ERA-40, including the representation of the hydrological cycle, the quality of the stratospheric circulation, and the consistency in time of the reanalysed fields. We provide ev