1Laboratoire d'Aérologie, UMR 5560 UPS/CNRS, OMP, Toulouse - France
2ONERA-CERT, Département Electromagnétisme et radar, Toulouse - France
Several thundercells have been observed by different devices in different locations of South-Europa. These devices consist of meteorological radar and Cloud-to-Ground lightning flash (CG) detection sensors. The radar data allow hail detection, precipitation rate evaluation and, in some cases, dynamic characteristics estimation. The detection of the hail within the thundercloud is possible thanks to diverse analysis techniques, especially when the cell is observed by two radar of different wavelength. The CG data provide the flash rate and density, the CG polarity and other characteristics like the number of lightning strokes and their intensity. Some of the observed thundercells exhibit hail-bearing cell features and others exhibit heavy precipitation rates without hail production. We compare the lightning activity characteristics of both types of thundercell. The CG rates corresponding to hail-bearing thundercells are singularly lower. Moreover, they produce higher positive CG proportions. Two cases are analyzed in detail in term of vertical structure, dynamics and temporal evolution. The CG activity seems to be well correlated with strong vertical velocities as a precursor factor (cloud charge production) and with the presence of liquid hydrometeors as a triggering factor (electric field enhancement).