POLARIZATION OF THE MULTIPLE SCATTERED SK YLIGHT OF THE ZENITH DURINGTWILIGHT

Results of measurements of intensity and polarization of the twilight sky in the zenith direction are given. These measurements were carried out with the polarimeter constructed on the base of 1-m telescope at two wavelengths: 0.48 and 0.69 mum. The observational point was on the slopes of Zailiysky Alatau mountains (2700 m MLS) and is characterize d with high, close to background level transparency of the atmosphere. Monte-Carlo method was applied to compute the single- and multiple sc attered intensity for background model of aerosols. Results of computa tions were used to estimate the degree of polarization of multiple sca ttered light directly from observational data. The values found were 0 .5 and 0.6 for red and blue regions of spectra, respectively. The comp arison of obtained values with known data of other authors was made.