Specific objectives are :   

  • to improve the global isoprene emission estimates from the MEGAN model by simultaneously taking into account the effects of climate, land use changes, and increasing CO2 levels through their impact on biomass fertilization and isoprene emission inhibition
  • to develop a consistent root-zone soil moisture dataset obtained by assimilation of the state-of-the-art in satellite surface soil moisture data (SMAP) and to validate using in situ data
  • to develop a new soil moisture stress parameterization relying on spaceborne SIF yield observations and on the satellite-based soil moisture dataset
  • to assess the model performance, in particular of its new soil moisture response to drought, by evaluating the seasonal and interannual variability of MEGAN isoprene emissions against in situ flux measurements and in situ soil moisture during droughts
  • to evaluate the isoprene emission anomalies of the MEGAN model through comparisons of multi-year satellite OMI HCHO data with HCHO columns simulated with the global IMAGESv2 model, over regions where isoprene is the dominant HCHO source
  • to test and possibly improve the parameterization applied in a case study of the exceptional 2018 drought over Europe by using simultaneously spaceborne observations of HCHO and SIF from the TROPOMI hyperspectral high-resolution spectrometer aboard the Sentinel-5 Precursor satellite (S5P).