Do we need GERB on MTG ?

Context

• GERB on 4 MSG’s approved, will provide 15 year dataset.

• First user consultation meeting on MTG focused on NWP, missing requirements: climate and chemistry.

• Climate expert meeting, 16/10/2002 : “… no need for a broad-band instrument in geo orbit in the long term. It would be enough to make use of the series of already planned GERB instruments in order to learn how to use spectral imagers for the purpose.”

Questions for the GIST

• Which studies/applications require more then 15 years of GERB data ?

• Are long term GERB measurements usefull if they are not global ?

• Can GERB be replaced by narrowband regressions calibrated by e.g. CERES ?