BIODIVERSITY – A NEW SPACE MISSION TO MONITOR EARTH ECOSYSTEM AT FINE SCALE

Abstract

Imaging spectroscopy has demonstrated an interest in characterizing the biochemical, biophysical and structural properties of vegetation, natural and agricultural soils, as well as artificial surfaces. Following the Hyperion mission, new space missions have emerged (PRISMA, EnMap), or are under study (CHIME, SBG). Most of these space missions have a ground sampling distance (GSD) of 30 m, a wide swath and thus they can cover large regions of the Earth simultaneously to characterize different terrestrial and oceanic ecosystems with a revisit period varying from 4 to 16 days. However, their spatial resolution is limited which induces a large number of mixed pixels reducing their potential to discriminate heterogeneous areas. The BIODIVERSITY mission aims to complement these space missions with a better GSD (typically 8-10 m), a 5-day revisit on targeted reference sites with identified and well-located characteristics. It will thus provide answer to two scientific issues that will design the instrument. The first issue concerns the spatial and temporal distribution of vegetation traits in species assemblages; these traits are associated with the resilience of terrestrial ecosystems, anthropogenic influences, and the biodiversity of ecosystems in terms of species composition and assemblages. The second issue relates to improving our knowledge of coastal areas and inland waters in terms of biodiversity, water quality and bathymetry, to assess the impact of human activity on their ecosystems. Finally, these two applications, which determine the specifications of the instrument, will be supplemented by the study, at fine spatial resolution, of the impact of soil management practices in an environmental process such as soil carbon sequestration, infiltration and retention, runoff or soil erosion. They also open new avenues for evaluating how urban materials influence our close environment and for characterizing urban and industrial pollution. The scientific challenges as well as the user requirements for such a mission are presented for each application.