M. A. Balmaseda, K. S. Mogensen, and A. T. Weaver, Evaluation of the ECMWF ocean reanalysis system ORAS4, Quarterly Journal of the Royal Meteorological Society, vol.39, issue.674, pp.139-1132, 2013.
DOI : 10.1029/2012GL051503

L. Debreu, ´. E. Neveu, E. Simon, L. Dimet, F. Vidard et al., Multigrid solvers and multigrid preconditioners for the solution of variational data assimilation problems, Quarterly Journal of the Royal Meteorological Society, vol.100, issue.694, pp.1-19, 2015.
DOI : 10.1016/S0377-0427(98)00133-2
URL : https://hal.archives-ouvertes.fr/hal-00874643

S. Gratton, A. S. Lawless, and N. K. Nichols, Approximate Gauss???Newton Methods for Nonlinear Least Squares Problems, SIAM Journal on Optimization, vol.18, issue.1, pp.106-132, 2007.
DOI : 10.1137/050624935
URL : http://www.reading.ac.uk/web/FILES/maths/09-04.pdf

P. Laloyaux, M. A. Balmaseda, D. P. Dee, K. S. Mogensen, and P. Janssen, A coupled data assimilation system for climate reanalysis', Q, J.R. Meteorol. Soc, issue.694, pp.142-65, 2015.
DOI : 10.1002/qj.2629

A. S. Lawless, N. K. Nichols, and S. P. Ballard, A comparison of two methods for developing the linearization of a shallow-water model, Quarterly Journal of the Royal Meteorological Society, vol.126, issue.589, pp.129-1237, 2003.
DOI : 10.1034/j.1600-0870.1993.00016.x

D. P. Mulholland, P. Laloyaux, and K. Haines, Origin and Impact of Initialization Shocks in Coupled Atmosphere???Ocean Forecasts*, Monthly Weather Review, vol.143, issue.11, 2015.
DOI : 10.1175/MWR-D-15-0076.s1

P. J. Smith, A. M. Fowler, and A. S. Lawless, Exploring strategies for coupled 4D-Var data assimilation using an idealised atmosphere???ocean model, Tellus A: Dynamic Meteorology and Oceanography, vol.135, issue.1, pp.67-217, 2015.
DOI : 10.1175/MWR3466.1
URL : http://www.tandfonline.com/doi/pdf/10.3402/tellusa.v67.27025?needAccess=true

A. Vidard, P. A. Bouttier, and F. Vigilant, NEMOTAM: tangent and adjoint models for the ocean modelling platform NEMO', Geosci. Model Dev, pp.1245-1257, 2015.
DOI : 10.5194/gmdd-7-6705-2014
URL : https://doi.org/10.5194/gmdd-7-6705-2014

A. T. Weaver, C. Deltel, E. Machu, S. Ricci, and N. Daget, A multivariate balance operator for variational ocean data assimilation, Quarterly Journal of the Royal Meteorological Society, vol.131, issue.41, pp.131-3605, 2005.
DOI : 10.1256/qj.05.119
URL : https://hal.archives-ouvertes.fr/hal-00125249