Multiple-truncation incremental approach for four-dimensional variational data assimilation
Article first published online: 15 DEC 2006
Copyright © 1998 Royal Meteorological Society
Quarterly Journal of the Royal Meteorological Society
Volume 124, Issue 550, pages 1889–1908, July 1998 Part B
How to Cite
Veerse, F. and Thepaut, J.-N. (1998), Multiple-truncation incremental approach for four-dimensional variational data assimilation. Q.J.R. Meteorol. Soc., 124: 1889–1908. doi: 10.1002/qj.49712455006
- Issue published online: 15 DEC 2006
- Article first published online: 15 DEC 2006
- Manuscript Revised: 3 OCT 1997
- Manuscript Received: 1 APR 1997
- Barotropic vorticity-equation model;
- Incremental approach;
- Quasi-continuous technique;
- Variational data assimilation
The incremental approach provides an approximate solution to four-dimensional variational data assimilation (4D-Var) at a reasonable CPU cost. An extension of this approach is studied, namely the multiple-truncation incremental technique, and is compared to the standard and single-truncation incremental implementations of 4D-Var, using a two-dimensional barotropic vorticity-equation model.
The quasi-continuous approach deals with the cut-off problem and spreads the computer requirements over time. Quasi-continuous incremental and quasi-continuous multiple-truncation incremental techniques are assessed.
The same number of iterations is specified in all the experiments. The multiple-truncation incremental technique is found to produce a good approximate analysis at a lower CPU cost. Applying the quasi-continuous approach to the incremental methods adds some benefit in terms of computer time.