Numerical simulation of the light field in the atmosphere-ocean system using the matrix-operator method

A computer code to calculate the light field in the stratified atmosphere-ocean system is described and validated. The code is based on the matrix-operator method and includes multiple scattering as well as the effects at the flat or rough sea surface and the ocean ground. Special emphasis is put on the methods employed to ensure numerical accuracy and energy conservation. The code is validated by comparing model predictions with the analytical solution of the radiative transfer equation for a semi-infinite Rayleigh scattering atmosphere and by a model intercomparison for selected problems of the radiative transfer in the atmosphere-ocean system. The observed deviations from the analytical solution are smaller than 0.1% for solar and observation zenith angles < 60<degrees>. The observed differences between the model predictions depend on the numerical difficulties encountered with the specific problem: they reach maximal values on the order of 5% for solar zenith angles < 60<degrees> and observation zenith angles < 30<degrees> in water and < 42<degrees> in air, respectively. (C) 2001 Elsevier Science Ltd. All rights reserved.