Requirement of minimal signal-to-noise ratios of ocean color sensors and uncertainties of ocean color products

Details

• Journal Title:
  Journal of Geophysical Research: Oceans
• Personal Author:
  Qi, Lin ; Lee, Zhongping ; Hu, Chuanmin ; Wang, Menghua
• NOAA Program & Office:
  NESDIS (National Environmental Satellite, Data, and Information Service) ; STAR (Center for Satellite Applications and Research)
• Description:
  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 Rrs in the visible wavelengths (ΔRrs(vis)) due to sensor noise in both the near-infrared (NIR) and the visible bands. While the former induces noise in Rrs(vis) through atmospheric correction, the latter has a direct impact on Rrs(vis). Such estimated uncertainties are compared with inherent ΔRrs(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.
• Keywords:
  Ocean Color Remote Sensing Ocean Color Remote Sensing
• Source:
  JGR Oceans 122(3): 2595-2611
• DOI:
  https://doi.org/10.1002/2016jc012558
• Document Type:
  Journal Article
• Rights Information:
  Other
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha256:1737e344ae803d86bf0a2dd2f9d48ca3777bc66a097d7f5c622e543fa3d7af20
• Download URL:
  https://repository.library.noaa.gov/view/noaa/43939/noaa_43939_DS1.pdf
• File Type:
  [PDF - 2.74 MB ]