ILAC: Radio and optical Lightning signals coupled to Atmospheric Chemistry measurements

ILAC (Impact of Lightning activity on Atmospheric Chemistry) is the combination of an electromagnetic sensor, an optical sensor and, an atmospheric chemistry instrument providing information on lightning, Ozone, NOX and other trace gas constituents.

The main objective of the ILAC mission is the evaluation of the effect of deep convection on the chemical and radiative equilibrium of the atmosphere. Additional mission objectives include, the characterization and identification of VHF sources radiated by lightning, lightning data fusion for storm nowcasting purposes and monitoring of global lightning activity as a proxy of global warming.

Climatological studies on the effect of LNOx and NOx on ozone chemistry need a permanent survey of lightning activity in the troposphere together with chemistry observations giving input to global 3-dimensional Chemistry General Circulation Models (CGCM) for the overall 3D modeling of the atmosphere. Reliable modeling evaluations need a validated parameterization of the subgrid LNOx and other NOx production rates.

Other space missions provide vertically integrated observations of trace gases in the atmosphere. Those valuable observations can be used to assess the present global states of the atmosphere and to compare the performances of the different CGCM used by the climatology laboratories. Those observations alone cannot be used to accurately predict the long term effect of the different natural sources like LNOx and soil emission through denitrification, and anthroprogenic sources like aviation, transport and biomass burning.

ILAC aims to provide observations of lightning activity and chemical composition which will be used to validate both global and mesoscale chemical transport models and their different parameterizations of LNOx production and NOx transport by deep convection.

ILAC consists of two satellite platforms. One, the Lightning Instrument Platform (LIP), is equipped with the lightning observation instruments and the other, the Chemistry Monitoring Payload (CMP), with an atmospheric chemistry instrument. The two platforms will be launched together and will fly on the same orbit providing the adapted time delay between the lightning and the chemistry observations.

Comparison of the space-borne measurements proposed here with ground based and air-borne measurements of lightning and chemical properties does allow to assess the quality of both types of data.