Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reduced-order 4D-Var: a preconditioner for the Incremental 4D-Var data
  assimilation method   This study demonstrates how the incremental 4D-Var data assimilation method
can be applied efficiently preconditione d in an application to an
oceanographic problem. The approach consists in performing a few iterations of
the reduced-order 4D-Var prior to the incremental 4D-Var in the full space in
order to achieve faster convergence. An application performed in the tropical
Pacific Ocean, with assimilation of TAO temperature data, shows the method to
be both feasible and efficient. It allows the global cost of the assimilation
to be reduced by a factor of 2 without affecting the quality of the solution.

14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat