ALBERT

Description: Optical observations carried out from low orbit satellites for twenty years have resulted in the first global map of lightning activity. Nowadays the current generation of geostationary meteorological satellites is equipped with lightning imagers like the European MTG (Meteosat Third Generation) LI (Lightning Imager). While on board the International Space Station, LIS (Lightning Imaging Sensor) and ASIM (Atmosphere-Space Interactions Monitor) instruments record optical lightning signal at different wavelengths, from near-UV to near-IR through imagery and photometry. Understanding the radiative transfer of light produced by the lightning discharges in the clouds is fundamental to interpret the detected optical signal. In this work, the forward three dimensional radiative code 3DMCPOL (Cornet et al., 2010) is adapted to simulate realistic lightning waveforms and images. The 3DMCPOL code usually models the light scattering by the cloud hydrometeors by using a Monte-Carlo method in a three-dimensional atmosphere, originally for solar or thermal sources. In the present study, a realistic 4-dimension (time and space) lightning source is considered and its detection at 337 and 777 nm by ground-based or space-borne photometers and cameras is simulated. The methodology will be first presented. Then realistic simulations of optical signal derived from the microphysical and electrical outputs of the French cloud resolving model Meso-NH will be discussed considering both imaging and photometry. Finally the main results will be related i) to the MTG-LI and ASIM observations, and ii) to the French-Israeli C³IEL (Cluster for Cloud evolution Climate and Lightning) mission under development.