## 3 Results
### Air Temperature  
Air temperature is the parameter that reflects the degree to which air is heated. Historically, air temperature was one of the first climatic parameters that scientists began to measure. When satellite missions were launched, they began to measure atmospheric temperature at various altitudes, e.g., sea surface or land surface. The most common method for satellite measurements is obtaining data using radiometric sounding. For this purpose, instruments that measure radiation in different wavelength ranges, most commonly infrared radiation allowing for calculating the temperature at specified heights, have been developed. The MERRA-2 reanalysis used upgraded instruments to measure vertical profiles of parameters such as air temperature and humidity--the CrIS Cross-Track Infrared Sounder (CrIS) and the Advanced Technology Microwave Sounder (ATMS) [19]. The CrIS Cross-Track Infrared Sounder is one of the most advanced hyper spectral instruments in the National Oceanic and Atmospheric Administration (NOAA) Joint Satellite System. CrIS is a high-resolution infrared spectrometer of which the operating principle is based on the separation of infrared energy emitted by the atmosphere, resulting in high vertical resolution. The instrument provides atmospheric sounding within 2,211  
Figure 11: Average rate of change in mean monthly anomalies of the soil upper layer moisture content (% per 10 years) for the period 1980–2021. spectral channels in three wavelength bands: long-wave LWIR (9.14-15.38 um), medium-wave MWIR (5.71-8.26 um), and short-wave SWIR (3.92-4.64 um) [44]. The Advanced Technology Microwave Sounder (ATMS) is a 22-channel scanning microwave radiometer for atmospheric and Earth surface observations, which makes observations in the microwave part of the electromagnetic spectrum. ATMS and CrIS provide data on the water cycle, namely, water vapor, clouds, and precipitation. Since clouds are non-transparent in the infrared part of the spectrum (as measured by the CrIS instrument), the two instruments work in combination to cover a broader range of weather conditions. ATMS provides a view inside and under clouds and can be used to study storms and hurricanes from the inside [45]. The MERRA-2 catalog presents temperature values for various altitudes: 2, 10, 42, 72 m, and at \"surfaces\" where atmospheric pressure is 250, 500, and 850 hPa. The atlas used air temperature values at 42.2 m above the ground surface. This makes it possible to analyze the data without taking into account the influence of wind, snow, and other surface factors. If we use the compiled maps for the purpose of climate forecasting, the general tendency of average air temperature increase since 1980 is clearly observed in Figure 12. This map shows the rate of change of the average annual air temperature. All values are positive, which means that for the specified time period, the temperature values are exclusively increasing. Additionally, we can distinguish the general trend--the more northward, the stronger the temperature changes are. In the area of the Novaya Zemlya Archipelago, the values of average annual temperature increase by 1 \({}^{\circ}\)C per 10 years. Since the studied area is located in the north, we can note extreme temperature values in winter periods, as well as characteristic areas where the cooling is not in contrast. Figure 13 shows a map of air temperature values for the whole period for January. The data indicate that the general trend of decreasing temperatures is directed from west to east--from near-zero temperatures north of the Kola Peninsula, to \(-\)26 \({}^{\circ}\)C in Taimyr and  
Figure 12: Average rate of change in mean monthly anomalies (relative to the annual rate) of air temperature at 42.2 m (\({}^{\circ}\)C per 10 years) according to NCEP/NCAR Reanalysis for the period 1980–2021. from \(-20\)\({}^{\circ}\)C to \(-24\)\({}^{\circ}\)C in Siberia. Zero temperatures, however, are present only in the oceanic part of the territory, which is explained by the influence of warm ocean currents.