Description of the Project

Scientific context

Tropical convection plays a fundamental role in the functioning of the climate system by transporting from the lower layers of the atmosphere to the free troposphere, air, water and momentum.
Although its study has been the subject of intense and rich scientific activity for decades, our lack of understanding of the vertical distribution of convective motions in the core of convective cells is now a major scientific lock.

Recent technological advances have enabled the design of miniaturized microwave instruments that are quite capable and, at the same time, inexpensive enough to consider the formation of a convoy of identical radars or radiometers in low-Earth orbit, separated in time by Dt ~ 1 minute, the temporal scale required to observe the highly nonlinear cloud dynamics present in convective updrafts

The mission

The C2OMODO project is supported by the French Space Agency CNES since 2019.

It inherits from the CNES expertise in microwave radiometry and more specifically from the SAPHIR microwave sounder from atmospheric humidity that operates on the Megha-Tropiques satellite (

C2OMODO will be the French contribution to the NASA « Atmosphere Observing System » ( and will provide original observations that will feed questions related to extreme weather and the development of storms.

The instrument : SAPHIR – NG

C2OMODO is a tandem of 2 identical microwave radiometers called SAPHIR – New Generation (SAPHIR-NG). The final specifications of SAPHIR-NG are currently under study between CNES and Airbus Defense and Space, but its main characteristics are:

  • 1 window channel at 89 GHz – instantaneous footprint size at nadir ~10 km
  • 6 channels in the 183.31 GHz absorption line (legacy of SAPHIR) – instantaneous footprint size at nadir ~ 5 km
  • 3 channels in the high frequency 325.15 GHz absorption line (legacy of ICI on MetOP-SG) – instantaneous footprint size at nadir ~ 3 km

=> This combination of observing channels will enable to map convective activity and development

In addition, on-ground processing specific to the use of time-delayed / delta-t maps are being developed jointly by Fluctus SAS and Informus GmbH and supported by CNES.

The C2OMODO Science Team

  • Hélène Brogniez (Laboratoire Atmosphères, Observations Spatiales – LATMOS) – PI –
  • Rémy Roca (Laboratoire d’Etudes en Géophysique et Océanographie Spatiales – LEGOS)
  • Jean-Pierre Chaboureau (Laboratoire d’Aérologie – LAERO)
  • Dominique Bouniol (Centre National de Recherche en Météorologie – CNRM)
  • Thomas Fiolleau (Laboratoire d’Etudes en Géophysique et Océanographie Spatiales – LEGOS)
  • Franck Auguste (Laboratoire d’Aérologie – LAERO)
  • Alexis Dépée (Laboratoire Atmosphères, Observations Spatiales – LATMOS)
  • Jean-François Rysman (Laboratoire de Météorologie Dynamique – LMD)
  • Laurence Picon (Laboratoire de Météorologie Dynamique – LMD)
  • Sophie Cloché (Institut Pierre-Simon Laplace – IPSL)
  • Christophe Dufour (Laboratoire Atmosphères, Observations Spatiales – LATMOS)

The CNES Team

The C2OMODO Science Team works closely with the « Instrumentation Radar and Performance » team of CNES : L. Hermozo, J. Puech, C. Goldstein and A. Mallet.

The project is managed by V. Cipolla and is developed within the Meteorology application area led by A. Deschamps.