Nonlinear Processes in Geophysics www.nonlin-processes-geophys.net 1023-5809 1607-7946 13 1 2006 10.5194/npg-13-67-2006 http://www.nonlin-processes-geophys.net/13/67/2006/ http://www.nonlin-processes-geophys.net/13/67/2006/npg-13-67-2006.html http://www.nonlin-processes-geophys.net/13/67/2006/npg-13-67-2006.pdf 67 81 2006-03-24 Detecting unstable structures and controlling error growth by assimilation of standard and adaptive observations in a primitive equation ocean model F. Uboldi uboldi@magritte.it A. Trevisan no current affiliation CNR-ISAC, Bologna, Italy Oceanic and atmospheric prediction is based on cyclic analysis-forecast systems that assimilate new observations as they become available. In such observationally forced systems, errors amplify depending on their components along the unstable directions; these can be estimated by Breeding on the Data Assimilation System (BDAS). 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