The Sentinel-5p TROPOMI OCRA/ROCINN retrieval is a two-step algorithm, with two model variants for the second step (ROCINN_CAL and ROCINN_CRB). OCRA computes the radiometric cloud fraction (RCF), ROCINN_CAL retrieves the cloud top height (CTH) and the cloud optical thickness (COT) and ROCINN_CRB retrieves the cloud height (CH, corresponding to the optical centroid) and the cloud albedo (CA).
The different quantities are validated as follows:
- The ROCINN_CAL cloud top height is compared to ground-based lidar/radar CTH measurements of the CLOUDNET and ARM network.
- Similarly, the ROCINN_CRB cloud height is compared to cloud mean height data, derived from the CLOUDNET vertical classification profile data.
- Several comparisons with cloud parameters of other satellite products are performed: NPP-VIIRS (CTH, COT), Sentinel-5p FRESCO (RCF, CH), Aura OMI O2-O2 (RCF, CH), MODIS (CTH).
Details on the methodology and results are described in Compernolle et al., AMT 2021.
Compernolle, S. et al., Validation of the Sentinel-5 Precursor TROPOMI cloud data with Cloudnet, Aura OMI O2-O2, MODIS and Suomi-NPP VIIRS, Atmos. Meas. Tech., 14, 2451–2476, 2021, doi:10.5194/amt-14-2451-2021.