Outputs from the project such as publications will be added to this website as the project progresses.
Publications
Marchese, C., E. Boss, F. Falcini, D. Doxaran, C. de Vargas, G. Pfister, and V.E. Brando. 2024. Satellite data sharing for scientific inter-group cooperation using the leaflet R package. Oceanography 37(3):70–74, https://doi.org/10.5670/oceanog.2024.513.
Abstract
Satellite observations have revolutionized ocean monitoring and analysis by providing a synoptic view of crucial marine environmental and biological data. By allowing planning of sampling locations based on observed biogeochemical patterns, satellite-based remote sensing data permit rapid and effective sampling of the full range of present conditions. Compared to traditional grid sampling, this technological advance has significantly improved sampling strategies of oceanographic campaigns. Sharing this crucial information in an accessible, user-friendly visual format promotes interdisciplinary research and collaboration. A strategy for such sharing, suggested here, is to integrate satellite data with interactive mapping tools, such as the leaflet, an open-source JavaScript library that can interactively visualize site-specific remote-sensing data. It produces customized maps that, because they are web-based, can be accessed from any device with an internet connection, making them useful for real-time collaboration among remote partners. Here, we demonstrate the practical application of the leaflet R package within the framework of the Tara Europa expedition, the ocean component of the Traversing European Coastlines (TREC) program, which has been using it to visualize satellite-derived data for selecting sampling stations and showcase its value in aiding researchers’ decision-making.
Jordan, TM, Simis, SGH, Selmes, N, Sent, G, Ienna, F and Martinez-Vicente, V. 2023. Spatial structure of in situ reflectance in coastal and inland waters: implications for satellite validation. Frontiers in Remote Sensing, 4. https://doi.org/10.3389/frsen.2023.1249521
Abstract
Validation of satellite-derived aquatic reflectance involves relating meter-scale in situ observations to satellite pixels with typical spatial resolution ∼ 10–100 m within a temporal “match-up window” of an overpass. Due to sub-pixel variation these discrepancies in measurement scale are a source of uncertainty in the validation result. Additionally, validation protocols and statistics do not normally account for spatial autocorrelation when pairing in situ data from moving platforms with satellite pixels. Here, using high-frequency autonomous mobile radiometers deployed on ships, we characterize the spatial structure of in situ Rrs in inland and coastal waters (Lake Balaton, Western English Channel, Tagus Estuary). Using variogram analysis, we partition Rrs variability into spatial and intrinsic (non-spatial) components. We then demonstrate the capacity of mobile radiometers to spatially sample in situ Rrs within a temporal window broadly representative of satellite validation and provide spatial statistics to aid satellite validation practice. At a length scale typical of a medium resolution sensor (300 m) between 5% and 35% (median values across spectral bands and deployments) of the variation in in situ Rrs was due to spatial separation. This result illustrates the extent to which mobile radiometers can reduce validation uncertainty due to spatial discrepancy via sub-pixel sampling. The length scale at which in situ Rrs became spatially decorrelated ranged from ∼ 100–1,000 m. This information serves as a guideline for selection of spatially independent in situ Rrs when matching with a satellite image, emphasizing the need for either downsampling or using modified statistics when selecting data to validate high resolution sensors (sub 100 m pixel size).