How many independent quantities can be extracted from ocean color?
B. B. Cael, Kelsey Bisson, Emmanuel Boss, Zachary K. Erickson
Abstract
Abstract Products derived from remote sensing reflectances (), for example, chlorophyll, phytoplankton carbon, euphotic depth, or particle size, are widely used in oceanography. Problematically, may have fewer degrees of freedom (DoF) than measured wavebands or derived products. Here, we show that a global sea surface hyperspectral dataset has DoF = 4. MODIS‐like multispectral equivalent in situ data also have DoF = 4, while their SeaWiFS equivalent has DoF = 3. Both multispectral‐equivalent datasets predict individual hyperspectral wavelengths' within nominal uncertainties. Remotely sensed climatological multispectral have DoF = 2, as information is lost by atmospheric correction, shifting to larger spatiotemporal scales, and/or more open‐ocean measurements, but suites of ‐derived products have DoF = 1. These results suggest that remote sensing products based on existing satellites' are not independent and should not be treated as such, that existing measurements hold unutilized information, and that future multi‐ or especially hyper‐spectral algorithms must rigorously consider correlations between wavebands.