Requirement of Minimal Signal-to-noise Ratios of Ocean Color Sensors and Uncertainties of Ocean Color Products

Authors

Lin Qi, Xiamen University
Zhongping Lee, University of Massachusetts Boston
Chuanmin Hu, University of South FloridaFollow
Menghua Wang, National Oceanic and Atmospheric Administrations, Center for Satellite Applications and Research, College Park, Maryland, USA

Document Type

Article

Publication Date

2017

Keywords

remote sensing, sensor design, signal-to-noise ratio, ocean color, atmospheric correction, noise reduction, uncertainties, remote sensing reflectance, chlorophyll a

Digital Object Identifier (DOI)

https://doi.org/10.1002/2016JC012558

Abstract

Using simulations, error propagation theory, and measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS), we determined the minimal signal-to-noise ratio (SNR) required for ocean color measurements and product uncertainties at different spatial and temporal scales. First, based on typical top-of-atmosphere (TOA) radiance over the ocean, we evaluate the uncertainties in satellite-derived R_rs in the visible wavelengths (ΔR_rs(vis)) due to sensor noise in both the near-infrared (NIR) and the visible bands. While the former induces noise in R_rs(vis) through atmospheric correction, the latter has a direct impact on R_rs(vis). Such estimated uncertainties are compared with inherent ΔR_rs(vis) uncertainties from in situ measurements and from the operational atmosphere correction algorithm. The comparison leads to a conclusion that once SNR(NIR) is above 600:1, an SNR(vis) better than 400:1 will not make a significant reduction in product uncertainties at pixel level under typical conditions for a solar zenith angle of 45°. Then, such uncertainties are found to decrease significantly in data products of oceanic waters when the 1 km pixels from individual images are binned to lower spatial resolution (e.g., 4 km) or temporal resolution (e.g., monthly). Although these findings do not suggest that passive ocean color sensors should have SNR(vis) around 400:1, they do support the argument for more trade space in higher spatial and/or spectral resolutions once this minimal 400:1 SNR(vis) requirement is met.

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Citation / Publisher Attribution

Journal of Geophysical Research: Oceans, v. 122, issue 3, p. 2595-2611

©2017. American Geophysical Union. All Rights Reserved.

Scholar Commons Citation

Qi, Lin; Lee, Zhongping; Hu, Chuanmin; and Wang, Menghua, "Requirement of Minimal Signal-to-noise Ratios of Ocean Color Sensors and Uncertainties of Ocean Color Products" (2017). Marine Science Faculty Publications. 1971.
https://digitalcommons.usf.edu/msc_facpub/1971