One of the outstanding results of the Indigirka (1926) and Kolyma (1929-1930) expeditions of Sergei Vladimirovich Obruchev was the forecast of the presence of an extensive gold-bearing belt in the Kolyma-Indigirka interfluve area of the Russian northeast, which later served as the “main foreign currency producing shop” of the country. According to the authors, the decisive role in this discovery was played by the meeting of Obruchev with Yury Bilibin. The meeting took place on the bank of the Kolyma River in July 1929. The forecast was based on information about the regional gold content of most of the Chersky Ridge, obtained in both Obruchev’s expeditions (1926 and 1929), and the discoveries of industrial gold placers made by the Bilibin’s expedition (1928-1929) in a small area of the southeastern end of the Ridge.

Currently, mobile laser scanning technology is increasingly used in large-scale topographic surveys of roads and adjacent areas and in the inspection of the roadway. The advantages of mobile laser scanning technology are the efficiency and accuracy of the results obtained. The article considers the main sources of errors that occur when shooting with the use of mobile scanning systems. The existing and proposed new ways to improve the accuracy of the results of mobile laser scanning are analyzed, as well as a technique for assessing their accuracy. Based on the analysis of survey accuracy indicators using mobile scanning systems, it was concluded that they can be used to perform large-scale topographic surveys of roads and the surrounding area. It was established that the main source of errors is the equipment of the global navigation satellite system (hereinafter referred to as GNSS), which is used to calculate the trajectory of a mobile scanner. Methods are shown by which it is possible to improve the accuracy of shooting in conditions of a weak or absent GNSS signal. The issues of evaluating the accuracy of the results of mobile laser scanning are considered. It is shown that if the exhibition parameters of the components of the mobile scanning system were carefully calibrated, then the main source of errors will be associated with the operation of the navigation unit and lidars.

In particular, with a complete or partial loss of the GNSS signal, as well as with a significant multipath effect, the accuracy of determining the position and orientation of the mobile platform will decrease.

Some methodological principles of assessment and mapping of the degree of anthropogenic change in landscapes are considered. The analysis of modern condition of landscapes of South Yakutia on the basis of the structural organization and the environmental state of natural complexes of different level. The landscape structure of Southern Yakutia is studied, the basic features of their differentiation are established. Assessment of the degree of anthropogenic impact is carried out at the main levels of ecological and geographical analysis of Yakutia: regional, local-regional, and local. At the regional level, the degree of anthropogenic disturbance of landscape regional complexes is revealed. Here data are presented on the changes in the selected research objects at the level of regional complexes. At the local-regional level, the degree of anthropogenic transformation of typological complexes within a certain physical-geographical region is determined. Disturbance of landscapes is determined by the ratio of the sum of the squares of disturbed landscapes with their weight coefficients to the area of natural landscapes. At the local level, the degree of anthropogenic change in landscapes is determined, expressed as a percentage. There are five degrees of disturbance of landscapes: unmodified, slightly modified, significantly modified, heavily modified and transformed landscapes. The proposed method for assessing the disturbance of natural landscapes was used for the following research objects in Southern Yakutia: at the regional level, the territory of the Aldan-Timpton interfluve is considered (scale 1: 500 000), the local-regional territory is the territory of the Neryungri industrial complex (scale 1: 200 000), the local one is the Elkon deposit (scale 1:25 000). Based on the results of anthropogenic change assessment and using GIS technologies, maps of the degree of anthropogenic transformation of the landscapes of South Yakutia were compiled. The analysis of anthropogenic impact on different spatial-hierarchical levels of landscapes made it possible to reveal the degree of disturbance of their natural state.

The aticle investigates the current state of affairs concerning the use of laser scanning results for the purposes of topographic mapping, cadastre and obtaining spatial information in Russia and abroad. The problems inherent in aerial laser scanning from manned and unmanned aerial vehicles (UAVs) are considered. In particular, for laser scanning systems installed on UAVs, there are constraining factors of their application, namely the existing organizational and legal restrictions on UAV access to airspace and ensuring flight safety, including at night. Laser scanning systems installed on manned aircraft are characterized by problems of high cost of equipment and software, as well as a limited and every year decreasing the number of specially equipped carriers capable of providing effective laser scanning from high altitudes.

The prospects and directions of laser scanning technologies application for the purposes of topographic mapping, cadastre, obtaining spatial information in order to create digital twins of territories and objects are shown. These prospects and directions are associated with the implementation of laser scanning technologies in the creation of cities with the millions of people in Siberia, the creation of an unified electronic cartographic framework (UECF), obtaining a very special type of product – high-precision topobathymetric laser surveying.

Proposals on the tasks requiring solutions for more intensive introduction of laser scanning technologies in the production works of Rosreestr and other departments are given. These proposals include the development on the basis of pilot production works of regulatory and technical documents, standards as well as the documents regulating the time and financial costs of work, taking into account new approaches to assessing the effectiveness of using of the laser scanning technologies. These approaches are associated with new types of products, multipurpose application of spatial information in various branches of the country’s economy, multiple the use of information on the principle of “received once, use repeatedly”.

Western Yakutia is famous for its mineral wealth. It is difficult to overestimate the role of exploration geologists of different generations who have contributed to its study. Today the diamond mining and oil and gas industries are developing most intensively in Western Yakutia. The extraction of minerals is preceded by the regional, prospecting and exploration stages of geological exploration. At the same time, the modern system of environmental regulation used in assessing the impact of geological exploration on the environment is insufficient and imperfect, especially for large-scale exploration for oil and gas. It is required to develop special environmental standards for environmental impact during the implementation of geological projects, taking into account various geographic, climatic and mining and geological conditions, based on the study of environmental and geochemical factors and assessment of the stability of landscape components of a particular territory to man-made impact. For the territory of Western Yakutia, studies were carried out to assess the geoecological safety of geological exploration. A register of disturbed sites was compiled; the areas of lands disturbed due to geological exploration were identified and calculated. The adaptation of the high-resolution satellite imagery interpretation technique for small-scale linear objects was carried out. The scale of geological prospecting technogenesis was revealed, which has a significant regional scale, while it has the prospect of spreading to the entire territory of Western Yakutia, including the shelf of the Laptev Sea. It will be hundreds of thousands of kilometers of clearings, a million square kilometers transformed into a network of geophysical profiles about 10 m wide. It should be noted that the consequences of such technogenesis are not known today, how the cryolithozone and the underground and surface hydrosphere will react, what will be the reaction of gas hydrates trapped in the bowels? Such a scale of work today can already influence the climatic processes of a regional scale, it is possible that they are to some extent to blame for the dry years following one after another in Central Yakutia. The work performed allows us to understand the scale of antropogenic impact, to look for ways to solve it, to form green exploration for the protection of our environment.

Thermokarst is one of the striking processes that characterize the dynamics of permafrost landscapes. It represents the process of soil subsidence due to thawing of underground ice. Under the influence of external factors, such as climate change, forest fires, deforestation, the invasion of silkworms, etc., there is an acceleration of the process of degradation of permafrost soils. The situation is also aggravated by the release of greenhouse gases trapped in permafrost soils, which, in turn, accelerate the process of climate warming. The study of thermokarst makes it possible to assess the scale of degradation of permafrost and to quantify the impact on climate warming.

Manifestations of thermokarst processes on ice-saturated soils of the Yanskiy plateau are considered. The climatic conditions of the investigated area, as well as survey geomorphological and lithological features of the distribution of soils on it. The degradation of permafrost under the influence of forest fires has been assessed. The thawing of underground ice in the “Chogoro” area was calculated according to the classification of the digital elevation model using the interpretation of images from unmanned aerial vehicles. The main methods of work are landscape cryoindication and remote sensing. Aerial photographs were processed using Topodrone, Agisoft metashape and ArcGIS software. A step-by-step method for calculating the volume of thawed ice in two areas is presented. The rates of degradation of frozen soils for key areas were revealed in the range from 5.2 to 10.5 cm / year. The volume of melted ice was 16364 m³ and 17985 m³.

Comparative analysis of landforms obtained from digital elevation models based on aerial photography data revealed a good correlation with a digital surface model based on satellite imagery data, which was confirmed by field measurements. The amount of ice that has melted indicates large-scale releases of greenhouse gases into the atmosphere, accelerating the rate of global warming. The rate of degradation of permafrost soils after forest fires on icy soils is undoubtedly intensified or accelerated.

Wild fires is an important factor in the functioning and transformation of geosystems. The aim of the study is to assess the impact of fires on the aquatic ecosystems of urbanized areas of the Middle Amur Lowland (within Khabarovsk Krai). The tasks of the work are to assess the burnability and pyrogenic transformation of the territory based on the analysis of long-term earth remote sensing (ERS) data series and to analyze the composition and patterns of post-pyrogenic changes in the bottom sediments of the key site (basin of the Simmi River, small tributary of the Amur River). Cloudless data of free access from Landsat 5, 7 and 8 satellites for 37-yr (1984 – 2020) were used to determine the average long-term characteristics of wildfires and trends in their changes. ERS processing was carried out by the expert decryption method in the ArcGIS 10.5 program.

The analysis of allocated wild fires indicates a significant scale and high repeatability of pyrogenic effects on the geosystems of the territory. Grass fires affected from 27 to 35 % of non-forest ecosystems, exceed 50 % in some years, which is comparable to the areas of forest fires. But according to official data, due to the imperfection of the methods of automatic mapping of the burnt-out territory, non-forest fires in the region account for only 8.9 %.

The bottom sediments were studied in the key site. Sampling (15 samples, according to standard methods) was carried out in May 2018 (in the third year after the autumn fire of 2016) and in July 2019 after the spring (March–April) fire. The main research methods were granulometric and gross chemical analyses and scanning electron microscopy (VEGA 3 LM scanning electron microscope, TESCAN, Czech Republic). The granulometric composition was determined by laser diffraction on a particle size analyzer (SALD-2300, Shimadzu, Japan). The gross composition was determined by X-ray fluorescence method (Pioneer S4, Bruker AXS, Germany). Our data indicate that the passage of grass fires in the catchment area entails a change in the chemical composition of BS formed in the post-pyrogenic period. In the first months after the fire, the reaction of the river system is the sequestration of soluble P compounds, which are formed during “fire” mineralization. This occurs as a result of the binding of phosphate ions into vivianite. It is precipitated on the surface of clay-ferruginous microaggregates of a suspended sediment fraction, which over time (2-3 years) is carried out by the stream. The latter leads to a reduction in the scale of the impact of the fire.