Integration of the VHF wind6profiler data within dual Doppler wind synthesis

During the Mesoscale Alpine Programme experiment, three Doppler weather radars and a VHF wind-profiler radar were deployed in the lago Maggiore area. The VHF radar was located in the area scanned by the weather radars. For IOP-2a (September 17-18, 1999), 3-D wind fields were retrieved from dual Doppler weather observations using the MANDOP analysis. In this paper, we present the impact on the reconstruction of the wind field when VHF wind-profiler radar data are used as an additional constraint among dual Doppler-radar measurements. The interest of VHF radar data is related to observations at the upper limit of, and above, the convective cell; and to the vertical wind measurements, not measured by Doppler weather radars. The experiment consists to integrate the horizontal wind, or the vertical wind and both of them in the retrieval. For each case, the difference between the reference and the new wind-field is computed. The positive effect of including VHF wind measurements in the upper layers, above 5km, is demonstrated in that it helps to get a better conditioning of the system, especially along the radar base line, which is the classical "hard region" for retrieving the three-dimensional wind field in a dual Doppler-radar configuration. (C) 2000 Elsevier Science Ltd. All rights reserved.