The New Nature Run and International Collaborations in OSSEs Need one or two new good nature runs which will be used by many OSSEs. Share the simulated data, compare the results. Nature Run: Serves as a true atmosphere for OSSEs Preparation of the nature run consumes a significant amount of resources. If different NRs are used the results can not be compared. Many nature runs will delay the delivery of the OSSE results. OSSEs are a very labor intensive project. Forecast runs forced by daily SST and ICE will be used for the Nature run.  Analysis is forced by observation and has jump in time evolution  Analysis is affected by the data assimilation scheme  Forecast run allows frequent sampling Analysis lacks the dynamical consistency

New Nature Run by ECMWF Based on Recommendations by JCSDA, NCEP, GMAO, GLA, SIVO, SWA, NESDIS, ESRL Low resolution Nature Run Spectral resolution : T511 Vertical level: L91 3 hourly dump Model: IFS cycle 31r1 Daily SST and ICE (Provided by NCEP) Period May 1, May 30, 2006 High resolution Nature run for selected period T799 resolution, 91 levels, one hourly dump Get initial condition from L-NR one six week periods To be archived in the MARS system on the THORPEX server at ECMWF Accessed by external users Copies in US for designated users (at NCEP NASA/GSFC, ESRL. SWA ) The simulation of the observation must be done from model levels and full resolution. Low resolution pressure and isentropic level data will be available for diagnostics and evaluation. A large number of standard diagnostic plots have been produced with the 'climplot' software by Adrian Tompkins at ECMWF. Cyclone track diagnostics is produced by Thomas Jung of ECMWF.

Contacts for the New Nature Run ECMWF Erik Andersson NCEP Michiko Masutani NASA/GSFC Lars-Peter Riishojgaard(GMAO), Oreste Reale(GLA), Joe Terry (SIVO) JCSDA John LeMarshall NESDIS Thomas J. Kleespies SWA Steven Greco ESRL Tom Schlatter Air Force Daniel Pawlak THORPEX Pierre Gauthier(DAOS), David Person(USA) Zoltan Toth (GIFS) Met Office Richard Swinbank Meteo France Jean Pailleux KNMI Gert-Jan Marseille JMAMunehiko Yamaguchi, Kozo Okamoto MRITetsuo Nakazawa ES Takeshi Enomoto EUMETSAT Jo Schmetz ESA Eva Oriol Extended international collaboration within Meteorological community is essential for timely and reliable OSSEs JCSDA, NCEP, NESDIS,NASA, ESRL ECMWF, ESA, EUMETSAT THORPEX, IPO Operational Test Center OTC – Joint THORPEX/JCSDA Data distribution A.The complete data set sent to NCEP and copied to ESRL and NASA/GSFC. B. Sample pressure level is posted at Nature run web site. User lists for each data sets are maintained by Michiko Masutani. Contact POC for your institute and provide all user’s Name, affiliation and address to Michiko to use above data set.