Development of a nationwide real-time 3-D wind and reflectivity radar composite in France.

The ability to perform multiple-Doppler wind synthesis from operational weather radar systems on an operational basis has been investigated by the French Weather Service since 2006 using a (sub-)network of six Doppler radars covering the Greater Paris area. This analysis has been recently extended to the entire French radar network so as to implement a nationwide, three-dimensional reflectivity and wind field mosaic to be eventually delivered to forecasters and modellers, as well as automatic nowcasting systems for air traffic management purposes. In this composite analysis, data collected by all 24 radars of the French radar network are collected, pre-processed and combined in real time at intervals of 15 minutes to retrieve the complete wind vector ( u, v, w) and reflectivity fields at a horizontal resolution of 2.5 km within a domain of approximately 1000 × 1000 × 12 km3. In order to illustrate the performance of this new product, examples of 3-D wind and reflectivity output produced during the passage of two significant weather events are presented: the extratropical storm Klaus, which struck France on 24 January 2009 with hurricane-force gusts, and a typical orographic high-impact precipitation event that developed on 21 October 2009. The evaluation of real-time radar outputs against operational analyses attests to the consistency of the retrieved wind fields. [ABSTRACT FROM AUTHOR]