Satellite Monitoring of Desertification in the Transitional Natural-Geographical Zone of the Volgograd Transvolga Region

Abstract

The northern part of the Volgograd Transvolga region is located in the transition zone from the Small Syrt to the Caspian lowland. This zone is characterized by a change in climatic conditions towards a decrease in the amount of precipitation and soil conditions, expressed in the transition from steppe to semidesert soil types. This condition of the lands is due to the peculiarities of the physical and geographical conditions of the transition zone and the influence of economic activity. As a result of monitoring, it becomes possible to monitor the processes of their degradation, leading to a drop in soil fertility. The use of monitoring results will make it possible to plan measures to neutralize the consequences of their degradation. The main results of studies of degraded lands in the Volgograd Transvolga region were obtained on the basis of satellite images of Landsat 7 and 8 over a 20-year period. Based on the study of the dynamics of changes in areas subject to degradation, geoinformation mapping of degraded lands was carried out from 1984 to 2020. A degradation assessment is carried out using geoinformation analysis tools and Earth remote sensing data in the research area. At the same time, changes in the area of degradation foci with a projective coverage of less than 10% were revealed, their spatial distribution was established, and the change in such an area over the period of research was established. The role of satellite images in the monitoring system is to timely establish changes in the state of the studied territory, including vegetation (projective cover); determine their area and spatial location; and clarify the geometric characteristics of research objects that can be identified on the displayed raster. The analysis of the state of the lands is carried out by the projective vegetation cover, which is most likely established by the tone of the image as the main characteristic of the satellite images raster and is identified as the individual objects under study. Currently, due to the aridity of the climate on the territory of the Volgograd Transvolga region, low natural soil fertility, and an abnormal economic load, the process of land degradation continues (Tkachenko and Koshelev, 2019). Degradation foci with a projective coverage of less than 10% average over 150 000 h. The growth of the area of such degradation sites is established in 1984, 1995, 1999, 2004, 2007, 2018, and 2020. The area of degradation sites in the study area in some years exceeded 300 000 ha, which is 100% higher than the average for the entire time of research. In this regard, monitoring of the Volgograd Transvolga region is of great importance for the timely detection of land degradation processes in arid conditions and the development of measures for their rehabilitation.