Determination of the anomalous refraction using meteorological data

This paper presents the results of determining the slopes of equiscalar boundary atmospheric layers above the Ulan Bator Astronomical Observatory using meteorological data. From these slopes, corrections to the apparent zenith distance of stars near the meridian have been computed. The corrections are found to vary during the day and year. The values are maximum in summer, minimum in winter. The sign of the correction during the day is always opposite to that during the night, and the correction is equal to zero in the morning and evening. The amplitude of these corrections is equal to 5 seconds of arc for zenith distance 85 degrees.