Uncertainties in Remote Sensing Reflectance From MODIS-Terra

A validation analysis of remote sensing reflectance (R_RS) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument onboard Terra (MODIS-T) is conducted with field R_RS data obtained at three fixed sites equipped with autonomous radiometers in the coastal northern Adriatic Sea and at two locations in the Baltic Sea, and during oceanographic campaigns in the Baltic, Black, and Mediterranean Seas and the English Channel. Validation results show mean relative differences |ψ| between satellite and field R_RS values of 10%-13% at 531 and 547 nm and 23%-36% at 667 nm. There are much larger deviations in statistics for shorter wavelengths with large |ψ| and bias values in the Baltic Sea. The root-mean-square differences tend to decrease with wavelength from 0.0011-0.0014 sr^-1 at 412 nm to 0.0002-0.0005 sr^-1 at 667 nm. Overall, the uncertainties shown for MODIS-T are very consistent with those associated with MODIS onboard Aqua.