Objective

The SMOS L-band Vegetation Optical Depth (L-VOD, τL also called opacity or tau) retrieved to estimate Above Ground Biomass (AGB) has shown the potential of passive microwave remote sensing to provide biomass estimates at the global scale. OSMOSE aims: 

• to improve AGB estimates from passive microwave sensors, such as SMOS, AMSR-E, and AMSR-2,
• to develop harmonized datasets of microwave band-specific band-VOD (τband) to assess evolutions of vegetation parameters (AGB, for instance) over the last 20 years from passive microwave sensors

While microwave brightness temperatures exhibit sensitivities to fresh woody components of vegetation, the optical domain is related to green Leaf Area Index (LAI), canopy structure, and leaf biochemical composition. It is therefore difficult to derive direct estimates of total AGB from observations in the optical domain, particularly for perennial crops that store most of their biomass in trunks, stalks, and branches which contribute marginally to optical canopy reflectance. Nevertheless, information on vegetation state variables derived from optical sensors can efficiently complement the ones derived from measurements in the microwave domain, and ultimately improve estimates of total AGB.

Role of CAPTE/EMMAH

Hongliang Ma, PostDoc, Marie Weiss & Frédéric Baret were in charge of

• Developing and validating optical vegetation water content products derived from MODIS, SENTINEL-2 and LANDSAT, based on the BV-NNET tool developed at EMMAH, previously used to derive operational products such as COPERNICUS GLOBAL LAND SERVICE LAI, fAPAR, fCOVER and Sentinel-2 SNAP toolbox biophysical variable tool.
• Develop long-term harmonized 1km datasets of LAI and fAPAR from MODIS, VEGETATION and PROBA-V products

Partnership

CESBIO, Magellium, GlobEO, WSL. See projet organization here