Vol 2023, No 2 (2023)

Seasonal and interannual variations of the aerosol optical depth (AOD) and the total carbon monoxide content in the atmospheric column have been determined by measurements of the MODIS and MOPITT instruments of the Terra satellite for several cities of the Irkutsk region and Buryatia with high level of atmospheric pollution for the period 2010–2021. For Irkutsk, a decrease of AOD interannual value from 0.278 in 2012 to 0.14 in 2020 with a general negative trend is shown. However, in 2021, the interannual AOD value for Irkutsk increased to 0.22. For Irkutsk, a negative trend of interannual variations in the total CO content in the atmospheric column is shown. When comparing the long-term seasonal variations of AOD according to ground measurements by CIMEL photometer in Tory (Buryatia), and the OMI/Aura satellite data, it was shown the proximity of AOD values for the summer and autumn seasons and a significant excess of AOT according to satellite data over ground measurements for the spring months. The largest Spearman correlation coefficient between ground and satellite measurements of AOD belongs to 2021 and is equal to ρ_s = 0.64.

The spatial distribution of the lithospheric magnetic anomalies field carries information about its sources – deep tectonic structures – and reflects the processes occurring at mantle depths. Based on the geomagnetic data measured by the CHAMP satellite at an observation altitude of ~290 km, the lithospheric magnetic field parameters over the territory of the African continent were calculated. A lot of maps of the lithospheric magnetic anomalies field total intensity T_a based on various scales and degrees have been constructed. The distribution of T_a over the territories of South and East Africa is given. An analysis of lithospheric magnetic anomalies maps over the territories of African superplume influence showed good agreement with the existing hypothesis about the mantle superplume flow intrusion from the lower mantle to the upper mantle in the northeast direction and its further spread under the East African rift zone. The obtained parameters of the anomalous lithospheric magnetic field contain information about the magnetization of the lithosphere deep layers, reflecting the magnetic properties of large regional tectonic structures and the topography of the Curie surface, which is associated with the geothermal regime and tectonic setting at different levels of the lithosphere. The work shows the perspective of the geomagnetic field satellite observations using in the study of the active zones tectonics and mapping of deep lithosphere heterogeneities in hard-to-reach areas.

The northern part of the Volgograd Volga 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 semi-desert 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 Volga region were obtained on the basis of satellite images of Landsat 7, 8 over a twenty-year period. Based on the study of the dynamics of changes in areas subject to degradation, geoinformation mapping of degraded lands was carried out in the period from 1984 to 2020. 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, as well as 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 into individual objects under study. Currently, due to the aridity of the climate on the territory of the Volgograd Volga region, low natural soil fertility, abnormal economic load, the process of land degradation continues (Tkachenko, Koshelev, 2019). Degradation foci with a projective coverage of less than 10% average over 150 thousand hectares. The growth of the area of such degradation sites is established in 1984, 1995, 1999, 2004, 2007, 2018, 2020 years . The area of degradation sites in the study area in some years exceeded 300 thousand hectares, which is 100% higher than the average for the entire time of research. In this regard, monitoring of the Volgograd Volga region is of great importance for the timely detection of land degradation processes in arid conditions and the development of measures for their rehabilitation.

The work considers the suitability of using multispectral satellite remote sensing data Landsat-8 for conducting regional geological and mineralogical mapping of the territory of south-eastern Transbaikalia (Russia) in conditions of medium- low-mountain relief and continental climate. The territory was chosen as the object of study due to its diverse metallogenic specialization (Au, U, Mo, Pb-Zn, Sn, W, Ta, Nb, Li, fluorite). Diversity in composition and age of ore-bearing massifs of intrusive, volcanogenic and sedimentary rocks are also of interest. Statistical processing algorithms to increase spectral information content of satellite data Landsat-8 were used; they include: principal component analysis (PCA); minimum noise fraction (MNF) and independent component analysis (ICA). Eigenvector matrices analysed on the basis of statistical processing results and two-dimensional correlation graphs were built to compare thematic layers with geological material classes: oxide/hydroxide group minerals containing transition iron ions (Fe³⁺ and Fe³⁺/Fe²⁺); a group of clay minerals containing A1–OH and Fe, Mg–OH; minerals containing Fe²⁺ and vegetation cover. Pseudo-coloured RGB composites representing the distribution and multiplication of geological materials classes was generated and interpreted. Integration of informative thematic layers with using fuzzy logic model was carried out to construct a prospectivity map. Received map was compared with geological information, and positive conclusions about territory suitability for further remote mapping research of hydrothermally altered zones and hypergenesis products in order to localize areas promising for identifying hydrothermal-metasomatic mineralization were made.

The model of the atmosphere in the form of a sequence of homogeneous layers 100 meters thick from the surface of the Earth to a height of 40 kilometers is considered. Layer parameters are defined for the standard atmosphere. Spectral sections 1002–1003 and 1020–1021 cm^–1 with opposite dependence of ozone absorption coefficient on its temperature change are selected. This model was transformed into one efficient homogeneous layer. The contribution to the outgoing radiation of the atmosphere in the selected spectral regions of the ozone absorption band (1002–1003 and 1020–1021 cm^–1) is equal to the contributions to the outgoing radiation of the Earth by all non-uniform layers constituting them. The possibility of adjusting the temperature of the Earth’s underlying surface is shown. The method of calculating the ozone content in the atmosphere by the outgoing radiation of the Earth is considered.