Estimation of Current Trends in the Monthly Mean Temperature in the Atmospheric Boundary Layer over Siberia

The trends in variation in the monthly mean temperature of the atmospheric boundary layer (ABL) are analyzed for January and July on the basis of data of radiosonde observations at 10 aerological stations in the Siberian region for the period from 1981 to 2020. Positive temperature trends are observed in the ABL at all the stations in January and July, except for the midlatitude zone (50-60 degrees N) of Western Siberia, where negative trends are noted in January. The values of the trends in temperature anomalies for the periods (1981-2010) and (1981-2020) are also compared. The comparison shows that warming has increased in polar latitudes in Western Siberia over the past 40 years, both in January and July, and the cooling is weakening in the subpolar and midlatitude zones in January. In Eastern Siberia, on the contrary, the warming has slowed down throughout the ABL in polar latitudes and increased in midlatitudes, especially near the Earth's surface, in January as compared to the period (1981-2010); the cooling has intensified in subpolar latitudes. In July, a decrease in warming is observed throughout Eastern Siberia at all ABL altitudes, except for polar latitudes, but only near the Earth's surface, where warming has increased.