Method for sea water absorption spectra estimation on the basis of shipboard passive remote sensing data and pure sea water properties

Abstract

An original method for calibration of spectra of the seawater surface radiance coefficient measured from onboard a moving ship with a three-channel optical spectrophotometer is proposed. The method is based on some characteristics of pure sea water absorption. Using this method, the sea water absorption spectra can be retrieved. Results of processing measurements in the Russian coastal area of the Black Sea near river mouths are given. The efficiency of the calibration method for radiance spectra measurements under variable clouds and wind is shown. The concentrations of the main natural seawater admixtures have been estimated from the absorption spectra retrieved, and the estimates have been compared with contact measurements in water samples. It is shown that the method developed for sea water analysis, which includes remote shipboard measurements of the seawater brightness coefficient, calibration of the spectra, seawater absorption spectra retrieval, and estimation of the main seawater admixture concentrations, can be used for the study of shelf and inland seawater areas because it does not imply any correlation between phytoplankton, dissolved organic matter (yellow substance), and suspended matter concentrations.