The energy exchanged between Earth and space was first estimated at the turn of the century. However, the ScaRaB instrument has been precisely mapping the planet’s radiation budget and its variations for 20 years now.

When CNES and CNRS, the French national scientific research centre, gave the go-ahead for the ScaRaB programme (Scanner for Radiation Budget) in 1986 as part of space cooperation efforts between France and Russia, global warming was already becoming a major concern. ScaRaB, designed to determine the contributors to Earth’s radiation budget, therefore followed the recommendations of the World Climate Research Programme (WCRP).

The ScaRaB instrument is a 4-channel radiometer capable of measuring incoming energy fluxes (solar radiation absorbed by the Earth system) and outgoing fluxes at the top of the atmosphere (infrared radiation escaping into space). It can thus monitor variations in these energy exchanges over time to gain new insights into Earth’s climate system.

CNRS’s LMD dynamic meteorology research laboratory conceived and developed the ScaRaB instrument with contributions from Russian and German laboratories, as well as the data processing software. CNES has coordinated with the Russian and German partners for the first two ScaRaB instruments and then Indian partners for the ScaRaB-3 instrument on the Megha-Tropiques satellite. It also processes and archives ScaRaB data in France and delivers them to users.