The calibration of an ocean-color sensor or validation of water products is generally based on ground-based extinction measurements from which the aerosol products (optical thickness τ a and aerosol type) are deduced. Sky-radiance measurements complement the extinction measurements mainly in the aerosol-model characterization. Our basic goal is to promote calibration-validation activities based on the radiative properties of the aerosols rather than their chemical or physical properties. A simple method is proposed (and evaluated) to convert sky radiances measured in the principal plane into atmospheric phase functions P. Indeed τ a and P are the required inputs to a radiative-transfer code for predicting the top-of-the-atmosphere radiances. The overall error in this prediction is a few percent. This method can operate on a worldwide network on ground-based sun radiometers and then be used to achieve a statistical analysis for validating satellite products.
© 2003 Optical Society of America
Original Manuscript: January 28, 2002
Revised Manuscript: August 23, 2002
Published: February 20, 2003
Richard Santer and Nadège Martiny, "Sky-radiance measurements for ocean-color calibration-validation," Appl. Opt. 42, 896-907 (2003)