Inter-sensor Level 1 radiometric performance assessment using Deep Convective Clouds Method: Application to Sentinel-2 and Landsat 8 and 9

The European Union (EU) created the Copernicus programme to achieve a global, high quality Earth observation capacity. The eyes of this programme are the Sentinel missions, and among them the Sentinel-2 mission provides high-resolution optical imaging in thirteen different bands, from visible to short-wave infrared. The Deep Convective Clouds (DCC) method is used to monitor inter-satellite level 1 radiometry in the framework of the Optical Mission Performance Cluster, an EU-funded Copernicus programme managed by the European Space Agency to assess the performance of optical missions. Sentinel-2 instruments MSI-A, B and C are monitored with this method along with Landsat OLI and OLI-2 instruments. Recent improvements in the methodology enabled an extension of the monitoring in the SWIR bands, up to 2200 nm, by computing spectral band adjustment factors (SBAF). These SBAF have been computed using hyperspectral DCC observations from the EnMAP mission. Results of this method show a good stability of the sensors, and relative differences of reflectance between MSI-A and B lower than 1% for all bands analysed, similarly for the relative difference between OLI and OLI-2, and relative difference between MSI units and OLI and OLI-2 lower than 3% for all bands analysed. The methodology will be presented in detail along with significant results. Consolidated results regarding the validation of MSI-C, especially during the tandem phase, will also be discussed.