VARIATIONAL ANALYSIS FOR AIRBORNE CONICALLY SCANNED DOPPLER LIDAR TO RETRIEVE MESOSCALE WIND FIELDS

An airborne pulsed Doppler lidar implementing a downlooking conical sc an rotating around the vertical axis is under development. The informa tion contained in the measured radial velocities is studied to assess the capacity to retrieve the 3D wind field at mesoscale. First, in the frame of a variational analysis, it is shown that the observations ca nnot resolve horizontal scales shorter than approximately 5 km. Then, constraints of mass conservation and regularity as well as various bou ndary conditions are added to improve the resolution. The various cons traints are tested on synthetic data. Further, a full analysis scheme is proposed that combines a preanalysis at low resolution followed by a finer resolution analysis. The achievable performances are discussed as well as the main limitations.