The retrieval of the complete velocity vector field from single-Doppler radar data is investigated with a simple Lagrangian 4DVAR method. This method combines the conceptually simple Lagrangian framework of Laroche and Zawadzki (1994) with the method of Xu et al (1995) in which source terms in the equations of motion are retrieved as part of the problem. Results are presented for an Oklahoma squall line and for a south Florida thunderstorm.

Key words: Doppler-radar, velocity-retrieval, 4DVAR