C3IEL, the Cluster for Cloud evolution ClImatE and Lightning Mission to Study Convective Clouds at High Spatial and Temporal Resolution

The space-borne C³IEL (Cluster for Cloud evolution, ClImate and Lightning) mission, jointly developed jointly by the French and the Israeli space agency, aims at providing new insights on convective clouds, at high spatial and temporal resolutions, close to the scales of the individual convective eddies. The mission will simultaneously characterize the convective cloud dynamics, the interactions of clouds with the surrounding water vapor, and the lightning activity.

The C³IEL mission consists in a short-baseline (~150 km) train of 2 synchronized small satellites. Each satellite carries a visible camera (670 nm) for cloud imagery at a spatial resolution of ~20 meters, near-infrared water vapor imagers (1.04, 1.13 et 1.37 µm ; ~125 m at nadir) measuring in and near the water vapor absorption bands, a lightning imager (777.4 nm ; ~140 m at nadir) and at two photometers (337 and 777.4 nm).

The scientific objectives of the C3IEL mission will be first reminded. They consist in documenting the convective cloud development through their 3D evolution and their environment with the retrieval of water vapor surroundings the clouds and the use of other observations such as geostationary satellite to characterize aerosol properties. In addition, the lightning activities created by such clouds will be observed. We will introduce the satellite train configuration, the different sensors of the mission and the innovative and different observational strategy that will be applied during daytime and nighttime. We will then detail the expected observations and products. Finally we will discuss the current status of the mission and the way forward.