Dependence of Satellite Ocean Color Data Products on Viewing Angles: A Comparison Between SeaWiFS, MODIS, and VIIRS

Brian B. Barnes, Chuanmin Hu

Research output: Contribution to journalArticlepeer-review

Abstract

<p> <p id="x-x-sp0075"> Despite widespread use of <a title="Learn more about Extraterrestrial Ocean from ScienceDirect's AI-generated Topic Pages"> satellite ocean </a> color data, measured radiance and derived geophysical parameters (e.g., <a title="Learn more about Remote Sensing from ScienceDirect's AI-generated Topic Pages"> remote sensing </a> reflectance or <em> R </em> <sub> <em> rs </em> </sub> , chlorophyll a concentration, <a title="Learn more about Absorptivity from ScienceDirect's AI-generated Topic Pages"> absorption and scattering coefficients </a> , diffuse attenuation coefficients) may show inconsistencies according to the sensor viewing geometry. In particular, data fluctuations based on sensor <a title="Learn more about Zenith Angle from ScienceDirect's AI-generated Topic Pages"> zenith angle </a> (SZA) can cause variable uncertainties in derived time series, as well as regional or global means. This study analyses single- and merged-sensor datasets from <a title="Learn more about Sea-Viewing Wide Field-of-View Sensor from ScienceDirect's AI-generated Topic Pages"> SeaWiFS </a> , <a title="Learn more about MODIS from ScienceDirect's AI-generated Topic Pages"> MODIS </a> , and <a title="Learn more about VIIRS from ScienceDirect's AI-generated Topic Pages"> VIIRS </a> for the <a title="Learn more about Gulf of Mexico from ScienceDirect's AI-generated Topic Pages"> Gulf of Mexico </a> region, finding pronounced variation within and between satellites as a function of SZA. Such effects are generally restricted to data with SZA above 40&deg;, although large variation exists between satellites and products. The non-tilted MODIS and VIIRS also show residual errors during summer time for SZA &lt; 30&deg; due to imperfect sun glint and <a title="Learn more about Bidirectional Reflectance from ScienceDirect's AI-generated Topic Pages"> bidirectional reflectance </a> distribution function (BRDF) corrections. Furthermore, certain algorithms and products are more resilient to angular dependence in <em> R </em> <sub> <em> rs </em> </sub> data. Overall, this study provides a framework for interpretation and account of SZA dependence in satellite ocean color data products, towards creation of cross-sensor time series as required for analysis of changes on multi-decadal scales. Finally, these findings can inform design and calibration of future geostationary sensors, for which targets have fixed viewing geometry. </p></p>
Original languageAmerican English
JournalRemote Sensing of Environment
Volume175
DOIs
StatePublished - Jan 1 2016

Keywords

  • Ocean color
  • Data continuity
  • Uncertainty
  • Sensor zenith
  • Time series

Disciplines

  • Life Sciences

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