Spatial Variability of In Situ Above-Water Reflectance in Coastal Dynamic Waters: Implications for Satellite Match-Up Analysis

The validation of ocean color satellite retrievals generally relies on analyzing match-ups between in situ measurements and retrievals. These analyses focus the quality data, however, same importance is data. Here, we present spatial variability above-water reflectance (R rs (0+)) within resolution different satellites—300, 900, 1500, 3000 m resolutions, mimicking Sentinel 3 OLCI MODIS-Aqua satellites, possible × 5 windows. Radiometric data was acquired with autonomous radiometric sensors installed British Columbia Ferry Services Inc. vessel “Queen Alberni” from May to September 2019, crossing optically dynamic waters Strait Georgia, Canada. dataset followed optimal geometry acquisition processing, including corrections for skylight radiance signals, ship superstructure, non-isotropic distribution water-leaving radiances, control. A total 33,073 spectra at full resolution, corresponding 10 days, were considered analysis presented here. results showed that, overall, subpixel increased as sensor or window size increased, mainly a linear fashion. Specifically, R (0+) largest (∼18% 68% 900 pixel respectively) Near Field Plume Interface waters, by Ocean Water (∼28% 35%, respectively), thus indicating heterogeneity interface waters. Further, found that estuarine higher (∼8% 16% m, compared plume oceanic We high primarily associated dynamics optical water constituents, limiting use these datasets Fiducial Reference Measurements satellite-derived atmospherically corrected reflectance. suggest should also be selection criteria good match-up especially coastal systems. As result, it will advocate exclusion transition grids order avoid compromising statistical result validation.