Reduction of error introduced in the processing of coastal zone color scanner-type imagery resulting from sensor calibration and solar irradiance uncertainty.

A combination of sensor calibration error and uncertainty in the solar irradiance can cause very large errors in the computations of the water radiance contribution to the Coastal Zone Color Scanner (CZCS) -measured radiances. This is especially true when the atmospheric correction algorithm is applied in a horizontally inhomogeneous atmosphere. These possible errors can be considerably reduced through spectral measurements of the aerosol optical thickness and upwelled subsurface radiances coincident with a CZCS overpass on a very clear day. For future instruments it is suggested that provision be made for the sensor to view solar irradiance in diffuse reflection. The analysis presented shows that with such a system the error is reduced to a level even below that which would be applicable if the solar irradiance were known precisely.