Following the evolutions implemented in the SYNERGY L2 and VGS softwares, quality assessments have been re-conducted at the end of year 2018 and confirmed the clear improvement of the SYN L2 and SYN VGT-P like products. In particular, the correlation between the Aerosol Optical Thickness data provided by SYN L2 and provided by AERONET stations are close and, despite a bias of 0.2 due to remaining cloud contamination, a regression slope of 1.12 can be drawn comparing these two datasets.
Similarly, we observe a high correspondence between TOA reflectances provided by SYN VGT-like products and the ones provided by Proba-V products. A regression slope close to 1 is observed on the BLUE, Red and NIR radiometric measurements. For SWIR measurements however, systematic large differences are observed and could be linked to the SLSTR calibration of SWIR channels.
Several major improvements have been progressively brought to the SYN L2 products during the year 2018. Besides several bugs corrected on the cloud handling and on the handling of Sun Zenith Angles, the global quality of the SYN L2 and SYN VGT like products have been increased as a result of:
- A reduction of cloud contamination with a more appropriate filtering of the cloudy pixels
- A discarding of the pixels flagged as affected by snow from the aerosol retrieval section.