The 3MI mission on-board EPS-SG: a multi-spectral multi-polarization multi-directional imager for operational characterization of aerosol and cloud.

The 3MI instrument is one of the missions of the EPS-SG program to be launched in 2021. This polarimetric mission is a heritage of the POLDER mission, with improved capabilities and now placed in a fully operational long-term framework. The spectral range was extended from the visible-near-infrared (410 to 910nm) to the shortwave infrared domain (up to 2200nm). The spatial resolution (4km at nadir) and the swath (2200x2200km(2)) were also improved compared to previous POLDER instruments. The 3MI concept of the multi-viewing, multi-spectral and multi polarized Imaging will be described, especially how these 3 information are acquired together with one instrumental concept that remains simple. The performance necessary to meet the mission requirements will be initially reached before launch through a fully dedicated ground campaign and maintained once in orbit through an extensive vicarious calibration strategy. The level 1 products available to the users will be geolocated Stokes vectors on the native geometry (Level 1B) and geoprojected multi-directional and spectral Stokes vectors (Level 1C). Level-2 products will provide geophysical and microphysical parameters for aerosol and clouds. The presentation will detail the 3MI concept, overview the mission characteristics, and browse the foreseen ground campaign and in-flight strategy necessary to reach the performance, as well as the products available to the users.