Marine Science Faculty Publications

Spectral Interdependence of Remote-sensing Reflectance and its Implications on the Design of Ocean Color Satellite Sensors

Document Type

Article

Publication Date

2014

Digital Object Identifier (DOI)

https://doi.org/10.1364/AO.53.003301

Abstract

Using 901 remote-sensing reflectance spectra (Rrs(λ),sr−1">��rs(��),sr−1Rrs(λ),sr−1 , λ">��λ from 400 to 700 nm with a 5 nm resolution), we evaluated the correlations of Rrs(λ)">��rs(��)Rrs(λ) between neighboring spectral bands in order to characterize (1) the spectral interdependence of Rrs(λ)">��rs(��)Rrs(λ) at different bands and (2) to what extent hyperspectral Rrs(λ)">��rs(��)Rrs(λ) can be reconstructed from multiband measurements. The 901 Rrs">��rsRrs spectra were measured over a wide variety of aquatic environments in which water color varied from oceanic blue to coastal green or brown, with chlorophyll-a concentrations ranging from ∼0.02">∼0.02∼0.02 to >100  mg  m−3">>100  mg  m−3>100  mg  m−3 , bottom depths from ∼1  m">∼1  m∼1  m to >1000  m">>1000  m>1000  m , and bottom substrates including sand, coral reef, and seagrass. The correlation coefficient of Rrs(λ)">��rs(��)Rrs(λ) between neighboring bands at center wavelengths λk">����λk and λl">����λl , rΔλ(λk,λl)">��Δ��(����,����)rΔλ(λk,λl) , was evaluated systematically, with the spectral gap (Δλ=λl−λk">Δ��=����−����Δλ=λl−λk ) changing between 5, 10, 15, 20, 25, and 30 nm, respectively. It was found that rΔλ">��Δ��rΔλ decreased with increasing Δλ">Δ��Δλ , but remained >0.97">>0.97>0.97 for Δλ≤20  nm">Δ��≤20  nmΔλ≤20  nm for all spectral bands. Further, using 15 spectral bands between 400 and 710 nm, we reconstructed, via multivariant linear regression, hyperspectral Rrs(λ)">��rs(��)Rrs(λ) (from 400 to 700 nm with a 5 nm resolution). The percentage difference between measured and reconstructed Rrs">��rsRrs for each band in the 400–700 nm range was generally less than 1%, with a correlation coefficient close to 1.0. The mean absolute error between measured and reconstructed Rrs">��rsRrs was about 0.00002  sr−1">0.00002  sr−10.00002  sr−1 for each band, which is significantly smaller than the Rrs">��rsRrs uncertainties from all past and current ocean color satellite radiometric products. These results echo findings of earlier studies that Rrs">��rsRrs measurements at ∼15">∼15∼15 spectral bands in the visible domain can provide nearly identical spectral information as with hyperspectral (contiguous bands at 5 nm spectral resolution) measurements. Such results provide insights for data storage and handling of large volume hyperspectral data as well as for the design of future ocean color satellite sensors.

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Citation / Publisher Attribution

Applied Optics, v. 53, issue 15, p. 3301-3310

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