The ERA-Interim reanalysis: configuration and performance of the data assimilation system

TitleThe ERA-Interim reanalysis: configuration and performance of the data assimilation system
Publication TypeJournal Article
Year of Publication2011
AuthorsDee, DP, Uppala, SM, Simmons, AJ, Berrisford, P, Poli, P, Kobayashi, S, Andrae, U, Balmaseda, MA, Balsamo, G, Bauer, P, Bechtold, P, Beljaars, ACM, van de Berg, L, Bidlot, J, Bormann, N, Delsol, C, Dragani, R, Fuentes, M, Geer, AJ, Haimberger, L, Healy, SB, Hersbach, H, Hólm, EV, Isaksen, L, Kållberg, P, Köhler, M, Matricardi, M, McNally, AP, Monge-Sanz, BM, Morcrette, J-J, Park, B-K, Peubey, C, de Rosnay, P, Tavolato, C, Thépaut, J-N, Vitart, F
JournalQuarterly Journal of the Royal Meteorological Society
Pagination553 - 597
Date Published04/2011
ISBN Number0035-9009
Keywords4D-Var, ERA-40, forecast model, hydrological cycle, observations, stratospheric circulation

Abstract 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 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.

Short TitleQ.J.R. Meteorol. Soc.