TY  - GEN
AU  - Cullen, M.J.
TI  - Use of potential vorticity as a control variable within a 4D variational data assimilation  system
T2  - ECMWF/Technical Memorandum
VL  - 358
PY  - 2002///
CY  - Reading
PB  - ECMWF
KW  - PREVISAO NUMERICA
KW  - IM
ER  -