Home – Home – Jornals – Geography and Natural Resources 2024 number 2

Based on data on air temperature as obtained at meteorological stations of Cisbaikalia, the dynamics of the continentality index over 90 years has been studied. An analysis was made of the dynamics of the continentality index in four circulation epochs in the Siberian sector (two zonal and two meridional epochs). The continentality was assessed by using the Gorczyński Continentality Index (GCI). The average long-term values of GCI in the study area are in the range from 51 to 86, which corresponds to the continental (33 < GCI < 67) and extreme continental (67 < GCI < 100) climate. A latitudinal growth of the GCI is clearly manifested. Minimum values were recorded at weather stations on the coast of Lake Baikal as well as at weather stations located in the central and southern parts of Irkutsk oblast, which are located on the coast of the reservoirs of the Angara cascade of hydroelectric power stations. It was found that with the zonal form of circulation, the continentality index either increases moderately or decreases at a slower rate than with the meridional form of circulation. An increase of the continentality index is observed at all weather stations at the second zonal circulation epoch (1977-2005). It is established that this is due to elementary circulation mechanisms (ECM) of the meridional northern group, the frequency of which at the second zonal epoch is twice as high as at the first epoch. The greatest contribution was made by sediment-forming ECM 12a, the duration of which since the late 1980s is twice as large as the long-term average. A distinctive feature of the weather stations on the Baikal coast is the positive trend of the continentality index at the last meridional epoch, while a negative dynamics is observed at the “continental” stations.