1. Barker, D. M., W. Huang, Y.-R. Guo, and Q. Xiao, 2004: A three-dimensional variational (3DVAR) data assimilation system for use with MM5: Implementation and initial results.Mon. Wea. Rev.,132, 897–914.
2. Courtier, P., 1985: Experiments in data assimilation using the adjoint model technique. Preprints.Workshop on High-Resolution Analysis, Reading, United Kingdom, European Centre for Medium-Range Weather Forecasts, 1–20.
3. Courtier, P., E. Anderson, W. Heckley, J. Pailleux, D. Vasiljevic, M. Hamrud, A. Hollingsworth, F. Rabier, and M. Fischer, 1998: The ECMWF implementation of three dimensional variational (3DVAR) data assimilation. Part I: Formulation.Quart. J. Roy. Meteor. Soc.,123, 1–26.
4. Courtier, P., J. -N. Thepaut, and A. Hollingsworth, 1994: A strategy for operational implementation of 4D-Var, using an incremental approach.Quart. J. Roy. Meteor. Soc.,120, 1367–1387.
5. Derber, J. C., 1985: The variational 4-D assimilation of analyses using filtered models as constraints. Ph.D. dissertation, University of Wisconsin-Madison, 142pp.