Polarization cloud detection with imaging polarimetry

Abstract

In this chapter we show some practical applications of 180° field-of-view (full-sky) imaging polarimetry. The concept and structure of some full-sky imagers (Total Sky Imager, Whole Sky Imager, All Sky Imager) widely used in environmental optics are presented. Some algorithms dealing with photometric cloud detection, a hot topic in meteorology, are described. A brief summary of the satellite-borne PARASOL/POLDER imaging polarimeter is given. Two versions of full-sky imaging polarimetry are described. Both use the measured extra polarization information of skylight. Their advantageous features are (1) enhancement of accuracy and reliability of cloud detection, (2) estimation of the relative cloud-base distance distribution in the sky and (3) applicability in solar forecasting, a very special current topic.