Long-term dynamics of open sand areas in the Astrakhan Volga region according to remote sensing data

Summary. The article presents an analysis of the relationship of climatic data with the dynamics of the areas of open sand massifs identified using remote sensing data in the south of the Astrakhan Volga region over the last decade (2014-2023).

Introduction. Throughout the entire territory of the Caspian lowland, including the Astrakhan Trans-Volga region, in recent years there has been an increase in the frequency and intensification of dust storms, while winds reaching deflation-dangerous speeds also lead to an increase in the areas occupied by open sands. The aim of the work was to study the dynamics of the areas of open sands for 2014-2023 and the influence of climatic factors (precipitation and wind conditions) on it.

Object. The study was conducted on the territory of the Kharabalinsky and Krasnoyarsk districts of the Astrakhan region (south of the Astrakhan Volga region). The territory is characterized by a flat relief and belongs to the dry-steppe and semi-desert natural zones.

Materials and methods. Mapping was carried out on the basis of visual interpretation of satellite images "Landsat-8, 9" (in "natural colors" and with the addition of IR) for the end of August and beginning of September. Data on wind conditions, dust storms and annual precipitation amounts from weather stations in Dosang and Kharabali were used. "QGIS" and "MS Excel" were used for processing raster, vector and statistical data.

Results and conclusions. According to the results of decryption, a total of 524 thousand hectares of open sands were identified for the entire period of the study (more than 160 thousand objects). The largest areas of open sands were identified in 2020, the smallest – in 2023. A strong positive relationship between the area of sand massifs and climatic factors (critical wind speeds and dust storms) was revealed. The reduction of the visible deciphered area of sands is associated with the growth of psammophytes, mainly annual. The results of the study are applicable in further studies of desertification in the Astrakhan region and adjacent regions, as well as in the development of reclamation measures.

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