Trends of climate change in Mountain Altai during post-soviet period

The Altai Republic is a representative region for studying climate change in the mountain areas of Northern Eurasia. Altai has a full set of high-altitude belts and significant landscape diversity, a large center of modern glaciation is located on its territory, it is an important water and climate divide separating the Arctic Ocean basin from the basin of internal runoff. In addition, there is a fairly long series of climatic observations in Altai. All this creates prerequisites for using the territory of the Altai Mountains as a model region to identify spatial patterns of climate change in mountainous countries. Monitoring and studying climate change in the Altai Mountains is an important and urgent task for Russia and the World, because in this region are located the largest glaciation areas. In the paper trends of air temperatures and precipitations in the Altai Republic are examined during three post-Soviet climatic decades: from 1992 to 2001, from 2002 to 2011 and from 2012 to 2021 used weather station data sets and two atmospheric reanalyses (NCEP/NCAR & ERA5). For the analysis, GIS technologies were used in Matlab using Mapping Toolbox. The magnitude of the linear trend in changes in average monthly air temperature for three periods in the Altai Republic demonstrates that from 1991 to 2001 and from 2012 to 2021 warming is recorded, the average rate of which in the post-Soviet decade is 1.7°C/10 years, and in the last decade—1.2°C/10 years. However, from 2002 to 2011, almost all weather stations in the Altai Republic observed negative values of linear trend coefficients, and the average cooling rate in this decade was -0.9°C/10 years. Climatic analysis of changes in the amount of precipitation in the Altai Republic on average over the past two decades shows a decreasing trend. The average rate of precipitation declines from 2002 to 2011 is -2.2 mm/10 years, and from 2012 to 2021— -11.0 mm/10 years. It is important to note that the reduction in liquid and solid precipitation is typical specifically for the western part of the Altai Republic.