Virtual constellation of Sentinel-2 and PlanetScope satellites to monitor forest ecosystems

Earth observation capacity, used to monitor forest ecosystems and characterize forest disturbances using satellite Earth observation data, has improved over the past few years, with the development of many algorithms that exploit dense time series at high spatial resolutions. In particular, a significant contribution to land monitoring is offered by Copernicus Sentinel-2 and cubesat satellite constellations, whose high revisit frequency, observation scenario, and guaranteed continuity have encouraged the development of operational monitoring services, also supporting sustainable ecosystem management. In particular, PlanetScope satellite constellation, consisting of more than 200 cubesat satellites, is able to image all Earth land nearly with daily frequency. Virtual constellations of satellites, integrating multiple sensors, allow for the generation of denser vegetation indices using a time series, helping to improve vegetation time trajectories, augment phenology estimation accuracy, and consequently enhance the monitoring capacity of forest ecosystems .
This research study compared and integrated a time series of various vegetation indices calculated from satellite Earth observation acquisitions over forest areas from Sentinel-2 MSI and PlanetScope DOVE and SuperDove satellite sensors. Time series were used to estimate phenological metrics and monitor the post-fire vegetation recovery of forest located at distinct phytoclimatic belts. Technical issues related to the use of virtual constellations of satellites, like radiometric normalization and spatial co-registration, were evaluated and discussed.
Results indicate that the exploitation of the medium-term time series of vegetation indices estimated from satellite data is a suitable tool that can be used to identify, describe, and monitor vegetation post-fire dynamics in ecosystems disturbed by wildfires. This research study demonstrates the ability of virtual satellite constellations to strengthen forest monitoring, highlighting the suitability of proposed approaches to develop operational services for supporting forests ecosystems surveillance, especially under climate change scenarios, supporting sustainable ecosystem management.