X-Band polarimetric and Doppler radar observations of heavy precipitation events over the Mediterranean region
Résumé
Numerous heavy precipitations take place over the western Mediterranean Sea especially during summer and in some case lead to severe floods over the continent (Vaison la Romaine 1992, Draguignan 15-16 June 2010, ...). Since the Mediterranean is surrounded by mountain barriers and strong contrasts between sea and continent exist, local forcing are important. This study aims to examine the environmental conditions and precipitation structures of storms in order to improve our knowledge about the life-cycle of intense events and processes that govern their evolution. It uses observations gathered by the X band polarimetric & Doppler weather Radar HYDRIX. This radar, developed by the LATMOS and operated by NOVIMET from the Mont Vial (mountain peak near Nice (France)), collects in an operational way since 2008 reflectivity, Doppler and polarimetric data with a time step and a spatial resolution of 5 minutes and 1 km respectively. In addition to these data, derived products such as instantaneous rainfall, cumulated rain, cell displacement and hydrometeor classification are obtained in real time. It also provides Doppler information in clear air region. All these data can be used to document the low level environment and the internal dynamics, microphysics and the interaction-mechanisms (wind shear, ...) leading to high-accumulated surface rainfall. The presentation focus on the first step of this work devoted to the temporal and spatial characterisation of the precipitation that affect the Provencal/Ligurian region. This is realized by means of a statistical analysis of these data to construct a climatology and to document the life cycle and the dynamical-microphysical characteristics of a few representative high-impact events.