24-Hour Change of the Polarization Pattern of the Summer Sky North of the Arctic Circle

Abstract

Using full-sky imaging polarimetry, Gál et al. (2001c) measured the polarization pattern of the summer sky in Sodankylä (Finnish Lapland), north of the Arctic Circle. Since at the place and time of their registrations the sun did not set, they could measure the 24-h change of the celestial polarization. This gave the opportunity to demonstrate how variable the degree of linear polarization p of skylight can be (Fig. 5.1A) and the position of the neutral points (Fig. 5.2) within 24 h on a cloudless, visually clear day.