SEASONAL AND LONG-TERM FEATURES OF SURFACE TEMPERATURE IN THE CITIES OF THE DRY ZONE

What is it about?

The artificial anthropogenic environment of modern cities greatly changes the surface temperature in comparison with natural landscapes. The presence of a large amount of spatial information allows you to compare different cities with each other, to investigate how strongly anthropogenic factors, in particular, the degree of sealing of the surface, affect the long-term course of temperature. Object. The research area is a region at the junction of the south-east of the European part of Russia and north-west Kazakhstan, located between 43 and 51 north latitude, 44 and 51 east longitude. In this area, 8 cities are selected – Saratov, Volgograd, Elista, Astrakhan, Makhachkala, Uralsk, Atyrau, Aktau. Materials and methods. The study is based on arrays of statistically processed data on the day and night temperatures of the earth's surface, obtained by the MODIS radiometer for the period from 2000 to 2020. Data on the degree of sealing and greening of urban areas were obtained during the decoding of Sentinel-2 satellite images. Results and conclusion. The classification of land use types based on Sentinel-2 satellite images revealed similarities and differences in the studied cities in terms of such indicators as the proportion of green and sealed surfaces, water bodies and agricultural land. The analysis showed a high proportion of sealed surfaces (six cities out of eight have this indicator over 30%). The group of the studied cities is carried out according to the features of the seasonal and long-term course of the daily maximum temperature. The latitudinal dependence of the nighttime temperature maxima, which increase when moving from north to south, is established. A comparison of the nighttime maxima of surface temperature with the degree of sealing of cities allowed us to conclude that the level of sealing in 40% and above is critical and contributes to the strengthening of the "heat island" over the city at night. It is revealed that as we move deeper into the continent, the uncertainty in predicting the date of the maximum daily surface temperature of cities increases.

Featured Image

Photo by Halima Bouchouicha on Unsplash

Photo by Halima Bouchouicha on Unsplash

Why is it important?

The article presents the results of comparing seasonal and long-term (20-year period) features of the earth's surface temperature in the cities of the arid zone of Russia and Kazakhstan to obtain information about the influence of natural meteorological factors and anthropogenic conditions, such as the degree of sealing and greening on the formation of the "urban heat island" effect on a regional scale.