Radiation factors climate formation in the Altai-Sayan mountain region in modern climate change period

Long-term (1965-2015) observations of actinometric stations were used to characterize the solar radiation regime in the Altai-Sayan Mountain Region. The paper presents the results of expedition actinometric observations in the Aktru Mountain Glacial Basin (the North-Chui Ridge) and the Multa Basin (the Katun Ridge). It is necessary to take into account climate resources for the develop-ment of mountain areas in Siberia and effective use in economic activities. The use of renewable sources of solar energy is becoming relevant for economic activities in the modern period. The regional feature of the indicators of atmospheric transparency in the mountainous regions of Siberia is revealed. The transparency of the air increases in the direction from north to south. Distribution’s regularities the sums of direct, scattered, total solar radiation, effective radiation and radiation balance are considered. The Altai-Sayan Region is characterized by a high transparency of the atmosphere. This factor is combined with the position of the region in the south of Russia, and contributes to the arrival of increased amounts of total radiation. The annual total radiation in the northern regions of the Altai and the Sayan mountains is 3900 MJ/m 2 per year, in the southern regions – 5600-5700 MJ/m 2 per year. Maximum values of total radiation are observed in mountain basins. Mountain valleys receive 25-30% less total radiation than basins due to the closed horizon and greater cloud cover. Average monthly amounts of total radiation decrease from west to east. The greatest changes are observed in summer and autumn. This is due to the features of atmospheric circulation. The largest increase in monthly amounts of total radiation in the north-south direction is observed in the spring and autumn. The article deals with current trends in the incoming solar radiation. In the modern period, the amount of direct radiation decreases, but the amount of scattered radiation increases. There is a tendency to decrease the annual total radiation amounts at all actinometric stations. In mountain valleys, a positive significant trend in the amount of radiation balance is observed throughout the year. In the warm period of the year, the growth rate of its values is much higher than in the cold period. In the Gornaya Shoria, positive trends in the radiation balance are observed during the cold period of the year. In the warm season, there is a decrease in the values of the radiation balance. There is a tendency to decrease the annual amounts of the radiation balance in the Altai-Sayan Region. The magnitude of trends in the radiation balance is within the limits of natural variability.