“…A comprehensive review of data assimilation in CPBM is provided by Gregg (2008). A collection of studies have been performed quite recently using ocean colour data, which demonstrate the value of the assimilation concepts inherited from optimal control or estimation theory (Hemmings et al 2003, 2004, Losa et al 2004, Friedrichs 2002, Garcia-Gorriz et al 2003, Ishizaka 1990, Armstrong and Sarmiento 1995, Natvik and Evensen 2003a,b, Gregg 2008, Nerger and Gregg 2007, 2008, Fontana et al 2009, Ford et al 2012, Hu et al 2012, Korres et al 2012, Roy et al 2012. Very often, variational data assimilation methods are implemented with the purpose of parameter estimation.…”