abstract
- After over one complete year of Copernicus Sentinel-2A satellite extended operations and with the mission prolonged until the end of 2026, we provide the first quantitative and globally consistent assessment of its added value to the Sentinel-2 mission. Using a pixel-level overview of cloud-, shade-, and snow-free (herein usable) observations, we show that despite reduced spatio-temporal coverage, the additional March 2025-2026 Sentinel-2A acquisitions enhanced the average number of usable Sentinel-2 observations at the global scale by 6.6 (20.81% increase with respect to the Sentinel-2B and -2C baseline). At the continental level, Sentinel-2A enhanced the mission's data pool most in Africa, where, on average, it added over 13 new acquisitions (>34% increase) and reduced average data-gap length by three days. In Europe, Sentinel-2A added, on average, 8.54 usable observations (>33% increase) and reduced average data-gap length from 19.51 to 16.87 days. Importantly, Sentinel-2A observations had the highest relative importance in regions with systematically lower temporal fidelity in the Sentinel-2B and -2C baseline, specifically the areas outside the orbit overlaps. At the global scale, Sentinel-2A boosted data availability for regions depicted from only a single orbit by over 31% (51% in Europe alone). Overall, our results demonstrate that the triplet Sentinel-2 constellation provides measurable improvements in temporal fidelity of the Sentinel-2 mission, thus likely enhancing the quality of Copernicus downstream products and operational services aimed at monitoring and managing terrestrial ecosystems and backing the EU's climate, agricultural policy, and sustainability goals.