Retrieval of nearshore bathymetry from Sentinel-2A and 2B satellites in South Florida coastal waters. (15th October 2019)

• Record Type: Journal Article
• Authors: Caballero, Isabel; Stumpf, Richard P.
• Is Part Of: Estuarine, coastal and shelf science. Volume 226(2019)
• Publication Date: 2019-10-15
• Subjects: Satellite-derived bathymetry -- Lidar -- Copernicus programme -- Atmospheric correction -- Surface correction; Estuarine oceanography -- Periodicals; Coasts -- Periodicals; Estuarine biology -- Periodicals; Seashore biology -- Periodicals; Coasts; Estuarine biology; Estuarine oceanography; Seashore biology; Periodicals; 551.461805
• DOI: 10.1016/j.ecss.2019.106277
• Languages: English
• ISSNs: 0272-7714

Abstract

Abstract: This study examines the relatively high-resolution MultiSpectral Instrument (MSI) onboard Sentinel-2A and 2B for generating bathymetric maps through a ratio transform model in South Florida (United States). Atmospheric correction of imagery is implemented though ACOLITE software, providing accurate performance and consistency over different Sentinel-2A/B scenes and three different study sites. Vertical calibration uses 5–10 points collected from digital charts, independent of lidar surveys, which are used for validation and error analysis. Satellite-Derived Bathymetry (SDB) has Median Absolute Error (MedAE) of 0.5 m in West Palm Beach (at depths ranging between 0 and 18 m, limit of lidar survey for validation), 0.4 m in Key West (0–5 m), and 0.22 m in Dry Tortugas (0–6 m), in conditions with low turbidity. Accurate bathymetry mapping can be accomplished with both sensors over environments with varying water transparency conditions, with the advantage of a fast, flexible, and economical solution. The 10-m MSI can capture small-scale features, such as tidal channels, straits relevant to navigation or steep slopes. While the least error is achieved by calibrating each image separately, a generic calibration produces only a moderately greater error with MedAE still ∼1m, indicating the robustness of the approach. The research highlights the great potential of the 5-day revisit, suggesting that the twin Sentinel-2 mission of the Copernicus programme may enhance SDB to leverage its use for several operational purposes, particularly in remote and inaccessible regions of the world. Highlights: The potential of Sentinel-2A and 2B to map shallow bathymetry at 10 m resolution is confirmed. Three tested sites are examined in South Florida under conditions of low turbidity. Few calibration points (5–10) from charts are required for vertical tuning of the ratio algorithm. Atmospheric correction with ACOLITE offers consistency and repeatability of performance. Comparison with lidar data provides median errors of ∼0.5 m for depths to at least 18 m.