|Title||The ERA-Interim reanalysis: Configuration and performance of the data assimilation system – This report is superseded by the version published in Q J Roy Meteor Soc.|
|Series/Collection||ERA Report Series|
|Authors||Dee, DP, Uppala, S, Simmons, A, Berrisford, P, Poli, P, Kobayashi, S, Andrae, U, Alonso-Balmaseda, M, Balsamo, G, Bauer, P, Bechtold, P, Beljaars, A, van de Berg, L, Bidlot, J-R, Bormann, N, Delsol, C, Dragani, R, Fuentes, M, Geer, AJ, Haimberger, L, Healy, S, Hersbach, H, Hólm, EV, Isaksen, L, Kållberg, PW, Köhler, M, Matricardi, M, McNally, A, Monge-Sanz, BM, Morcrette, J-J, Peubey, C, de Rosnay, P, Tavolato, C, Thépaut, J-N, Vitart, F|
|Event Series/Collection||ERA Report|
|Place of publication||Shinfield Park, Reading|
ERA-Interim is the latest global atmospheric reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ECMWF), covering dates from 1 January 1989. 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 20th century. This article describes the forecast model, data assimilation method, and input data sets 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 evidence for substantial improvements in each of these aspects. We also identify areas where further work is needed and describe opportunities and objectives for future reanalysis projects at ECMWF.