La polarimétrie radar à Météo-France

EnglishThis paper presents a summary of the experience gained atMeteo-France on the use of polarization in the S, C and, more recently, X-band. After eight years of experience at Meteo-France, it appears that polarization clearly helps to improve the quality of all radar products, through a better identification of non-meteorological echoes (in clear air), the ability to correct for attenuation, which allows to better estimate the rain rate, especially at high rain rates, and identify the type of hydrometeor. In order to exploit fully polarization, it is absolutely necessary to implement rigorous procedures to monitor the calibration of polarizing variables and detect and correct for potential biases. A polarization processing chain has been introduced into operations on all polarized radars (except the X-band which are still being tested) in 2012. This processing chain, applicable to the three wavelengths (S, C and X) will undergo regular upgrades in the coming years. francaisCet article dresse un bilan de l'experience acquise a Meteo-France sur l'exploitation de la polarimetrie en bande S, C et, plus recemment, X. Apres pres de huit annees d'experience a Meteo-France, il apparait que la polarimetrie permet clairement d'ameliorer la qualite des produits radars, au travers notamment d'une meilleure identification des echos non meteorologiques (ciel clair), d'une capacite a corriger de l'attenuation, a mieux estimer le taux de precipitations, notamment sur les pluies fortes, et a identifier le type d'hydrometeores. Pour tirer pleinement benefice de la polarimetrie, il est indispensable de mettre en place des procedures rigoureuses de suivi temporel de l'etalonnage des variables, de detection et de correction des biais eventuels. Une chaine de traitement polarimetrique a ete rendue operationnelle sur tous les radars polarimetriques (a l'exception des radars en bande X, encore en cours de qualification) en 2012. Cette chaine de traitement, applicable aux trois longueurs d'onde (S, C et X), sera regulierement amelioree au cours des prochaines annees.