The atmospheric correction of ROCSAT-1 OCI imagery - Part II: OCITRAN-2

The algorithms used to establish the atmospheric correction model, OCITRAN-2, are demonstrated in detail. This study uses the difference between the total radiance and the Rayleigh scattering radiance at 865nm to determine the air mass character for estimating the aerosol scattering radiance and the water leaving radiance. The result indicates a high correlation between the estimates using the OCITRAN-2 and the SeaDAS models. Detailed analysis shows that the correlation coefficient can be up to 0.83 when the chlorophyll concentration is less than 10 mg/m³. The OCITRAN-2 result was more accurate than that of the OCITRAN-1 using the concept of clear water method, indicating that the improvements in multiple Rayleigh scattering in the OCITRAN-2 are solid. Analysis results also suggest that the process to reduce the radiance contamination by neighboring cloud edge and thin cloud pixels should be improved.