NISAR: Seeing Beyond the Trees to Understand Wetlands, Forests and Biodiversity

Globally, wetlands are a critical habitat of numerous plants and animal species and play a major role in maintaining Earth’s biodiversity. Wetlands ecosystems are particularly challenging to characterize and monitor because many tend to be in remote regions that are difficult to access. As optical satellite remote sensing instruments observe only the top of the canopy, they are limited in they cannot directly observe surface inundation beneath vegetation canopies. The NISAR mission is tasked with mapping surface inundation in wetlands. NISAR’s unique capability enables consistent and reliable observations of wetlands inundation extent and dynamics. This capability supports characterization of changes in wetlands systems driven by a changing climate and will support a better understanding of the impacts to carbon fluxes, ecosystems services and biodiversity in these critical systems.Focusing on our efforts in Pacaya Samiria Nation Reserve, Peru, we provide an overview of NISAR’s capability to study wetlands ecosystems. Pacaya Samiria has been selected to be the NISAR calibration-validation site for tropical wetlands. Here, we have established a network of in situ sensors for validation of inundation state and extent in a complex tropical wetlands environment. Our sensor network is supported by ancillary measurements of vegetation structure drawn from drone and ground LiDAR and photogrammetry. We also describe the calibration validation approach that will be implemented as part of supporting the NISAR objectives, and we present preliminary results using ALOS PALSAR-2 data and possibly first light images from NISAR.