ИСТИНА

The features of temperature stratification in the surface boundary layer of the atmosphere have a great influence on the microclimatic conditions, as well as on the spatial distribution of various pollutants. Temperature inversion is one of the key phenomena creating severe meteorological conditions and contributing to the accumulation of pollutants in the surface layer of the atmosphere. In accordance with long term observations, it can be stated that the Arctic region is prone to the formation of temperature inversions (observed on more than 30% of the days), especially on the winter season. What is more, the cities in the described area experience a formation of strong “urban heat islands”. This phenomenon of spatial distribution is characterized by an increase of air temperature in the city center compared with its surroundings. It reaches its greatest strength and prominence in the cold season, when the differences in the temperature are the greatest. In consideration of the aforementioned climatic patterns, the city of Apatity, Murmansk region, was chosen as a testing ground for studying the climatology of polar cities, in particular, in order to study the fine structure of surface inversions, their changes over time, and interaction with the urban heat island. To study the fine vertical structure of inversions, vertical sounding was performed using thermal “braid” (rising to a height of 100 m, the sensors were installed every 10 m) and quadrocopters equipped with temperature sensors (rising to 200-250 m). To study the characteristics of the inversion within the urban heat island and in the background area temperature profiles through the city of Apatity were created using iButton temperature sensors. Gradient masts with temperature sensors at altitudes of 1.5 and 3 m were installed in the center of the city and in the background area. Netatmo sensors were also used to monitor changes in weather parameters in real time. All observations were carried out in homogenous synoptic conditions set by an anticyclone ridge of an area of high pressure centered over the Kara sea. During the study, the fine structure of the surface inversion was considered for the first time, both at night and at daytime. Under the conditions of an intensive surface inversion, vertical soundings of the surface layer of the atmosphere were carried out in the lower 100 meters using a DJI 4 quadrocopter. As a part of the experiment, temperature profiles obtained by iMet-XQ, iMet-XF sensors and the 10 iButton thermal “braid” were compared. The acquired results showed great similarities with each other. Also, simultaneous sounding in the urban and background points demonstrated noticeable differences in the intensity of surface inversions, which, apparently, is the result of the influence of the urban heat island of Apatity. Horizontal soundings were also performed using a mobile measuring complex consisting of an automatic meteostation (AMS). The soundings verified the readings of both iButton sensors installed throughout the city and 2 AMS Davis Vantage Pro 2. What is more, the acquired results showed a more detailed image of temperature distribution in the city. Under the conditions of anticyclonic weather, the spatial heterogeneity of temperature within urban landscapes was considered by analyzing the readings of the iButton sensors and data from two AMS Davis Vantage Pro2. The contrasts of air temperature observed simultaneously according to measurements at a height of 2 meters within and outside the city reached 10°C. It was shown that under favorable synoptic conditions in the city, a powerful heat island is formed, which is a key factor influencing the spatial temperature distribution in the city and its surroundings. In addition to meteorological measurements, a basis was laid for subsequent microscale modeling of atmospheric processes inside the urban canopy, for which, as a result of route observations, the online database of available data on the shape and height of buildings of the central core of the city of Apatity was finally completed. Moreover, the assessment of the accuracy of mesoscale forecast modeling was performed. The evaluation was based on the ability of the models to predict the phenomena mentioned above using the WRF-ARW modelling package