Correction of the stratospheric aerosol radiative influence in the POLDER measurements

This paper presents the principles and performances of the stratospheric aerosol correction schemes for the Polarization and Directionality of the Earth's Reflectances (POLDER) spatial polarimeter measurements and the method used to derive, from the Stratospheric Aerosol and Gas Experiment II (SAGE II) data, the information about the aerosols that is needed for the correction. On the Advanced Earth Observing Satellite (ADEOS) platform since August 1996, POLDER performs multidirectional measurements, both of reflectance and of polarization in visible and near-infrared spectral bands. These new observational capabilities are used to observe clouds, lands, ocean surfaces, and tropospheric aerosols. These observations are weakly perturbed by the stratospheric aerosols, whose amount is currently low, but in the case of a major volcanic eruption, would increase strongly for few years. The possibility of such a situation has to be considered. Moreover, even near background conditions, the stratospheric aerosols perturb accurate retrieval of the ocean color and products deduced from the polarized light. That is why a systematic correction of their influence on the measured signal has been developed.