where Ed(a) is the down welling irradiance above the water surface, d*
diffuse and
d*
direct are the diffuse and direct ground-to-sensor transmittance, Rapp is the target
apparent reflectance and Aapp is the average background apparent reflectance.
The atmospheric correction of the hyperspectral images was performed with
the in-house software WATCOR. WATCOR uses the radiative transfer code
MODTRAN-4. The at-sensor radiance is converted to apparent reflectance Rapp.
The apparent reflectance Rapp can be estimated from the at-sensor radiance Lrs