The French radar network and products: achievements and outlook

The number of weather radars in the French metropolitan radar network (ARAMIS) has increased from 13 radars in 1995 to 28 in 2014 and will reach 31 in the very near future. Météo France also operates 7 overseas S band radars and with the recent addition of 4 X band radars in the Alps, 3 wavelengths, S, C and X are now being used in the network. All the radars are Doppler and operated with a triple PRT scheme that allows velocity measurements up to maximum range (250km). Dual polarisation has become the standard with dualpol parameters zdr, rohv, phidp available from 20 metropolitan radars and from one radar overseas.

The densification of the network and the operational use of dual polarisation have greatly contributed to improving the quality of the national QPE mosaic that is produced every 5 minutes at the spatial resolution of 1km² and delivered 2 minutes after data time. This success has also fuelled the demand for equivalent QPE products in the overseas territories and for the design of new products for various applications (nowcasting, hydrology, numerical weather prediction, aviation, climatological studies and even bird migrations monitoring...).

In spite of the large increase in the number of radars, parameters, data volume and products, the number of dedicated staff resources has remained constant and greater efficiency had to be found throughout the changes to maintain the quality of the products while developing new ones.

In this paper, we will give an overview of the most recent developments that include: the design and development of a new centralised processing platform that can ingest polar volume scans from any radar (including foreign ones in ODIM format) and generate all the single site products and composites in less than a minute, the operational implementation of a new version of the dualpol processing chain that can be used at all frequencies (including X band) and that delivers improved rain rates (using kdp that is insensitive to beam blockages, attenuation or the calibration of the radar) and hydrometeors types, the operational implementation of new spatialized gauge adjustment procedure that improves significantly QPE at intermediate (80-150km) and long ranges (>150km).