Simulation of MOS spectra by radiative transfer calculations using ground-truth data and atmospheric models

Abstract

A radiative transfer simulation technique (RTST) is described that is applied to simulate spectral signatures recorded by the ocean colour sensor MOS onbo-ard the IRS-P3 platform. The RTST is based on a successive order technique and considers ab-sorption and multiple scatte-ring of solar radiation by particu-late and molecu-lar species. Aerosol optical depths are retrieved from ground-based solar absorption measurements while the scattering phase functions are primarily determined from almucantar measurements and are then fitted by two- or three-term Henyey-Greenstein functions. Quasi-mono-chro-matic line-by-line calcu-lations are used to predict molecular trans-mission functions at 10 nm spectral resolutions in a layered atmo-sphe-re. The inherent pure sea water reflectance and reflection functions due to solar and sky glitter effects are considered in the simulations by use of ground-based measurement data as well as model assumptions. Synthetic VIS and NIR spectra that have been calcula-ted in the 400-1700 nm wavelength range for a varie-ty of atmo-sphe-ric mo-dels and surface condi-tions are compared with selected MOS measurements.