Purpose is quantitative estimation of the mass of emissions of combustion products, chemical elements, the energy and power of acoustic and thermal radiation caused by the forests large tracts burning in the Northern Hemisphere. Methods. Analytical review of investigation problem, theoretical and computational, numerical modeling, system analysis. Results. It was found that large-scale fires in the Northern Hemisphere in 2020 had catastrophic ecological consequences. The greatest contribution was made by the burning of forests in Russia and the USA. Ecosystems were affected on an area of about 15 million hectares. About 3,5 Gt of wood was irretrievably lost. About 140 Mt of smoke and more than 10 Mt of soot were emitted into the atmosphere. The mass of the injected CO gas was about 350 Mt. The mass of hydrocarbons emitted into the atmosphere was about 140 Mt. About 7,8 Gt of CO2 gas was additionally emitted into the atmosphere. Hundreds of megatons of atomic nitrogen, hundreds of tons of potassium and calcium, as well as from units to tens of tons of such chemical elements as Fe, Zn, Cr, Br, Mn, Pb, Rb, Sr and Se have been emitted into the atmosphere. The energy of acoustic radiation was about 100 PJ, which is almost a thousand times higher than its energy under normal conditions. The energy of weakly damped infrasonic radiation was 1–10 PJ. The thermal radiation flux density reached 56–160 kW/m2. Even after the distribution of forest combustion products around the globe, their concentration exceeded the concentration under normal conditions. This primarily applies to smoke, soot and carbon monoxide. The economic damage amounted to about 750 billion US Dollars. Dozens of people died and were injured. Material and moral damage has been caused to many thousands of people. Material and moral damage caused to many thousands of people. Conclusions. The ecological consequences of the forests large tracts burning of Northern Hemisphere in 2020 for the planet became a kind of record.

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Topicality. There is an urgent need to select the main energy, geometric and thermophysical parameters of forest fires, as well as to assess the main parameters of these fires, including unexplored fire tornadoes and wave processes caused by fires. Purpose. To develop mathematical models of physical processes caused by large-scale forest fires, evaluate the main parameters of these fires, including unexplored fire tornadoes and wave processes caused by fires. Methods. Analytical review of the research problem, theoretical and computational, mathematical modeling, systematic analysis of the set of physical effects. Results. The results of the analysis of the parameters of forest fires and related physical processes caused by large-scale fires are presented. The main energy, geometric and thermophysical parameters of large-scale forest fires are proposed. These include: energy, power, duration, area of fires, as well as the length, intensity and speed of the combustion front, heat flux density, power flux density, torch height, heat and smoke rise height, convection speed, etc. Simple analytical physical and mathematical models of the main parameters of large-scale forest fires have been created. A model of a fiery tornado is proposed. The obtained ratios allow us to estimate the main parameters of fire tornadoes that accompany large-scale forest fires. These include radius, angular velocity, tangential velocity, maximum height and rate of rise of the heated formation. It is shown that, depending on the size of the vortex, the parameters of the fiery tornado vary widely. These relationships make it possible to analyze and evaluate the main parameters of wave processes generated by forest fires. Such parameters are energy, relative share of energy, range of periods of acoustic radiation, etc. The main parameters of forest fires and related physical processes are calculated. It is shown that depending on the area of the fire, these parameters vary widely. Conclusions. Mathematical models of physical processes caused by large-scale forest fires have been developed, by means of which the parameters of the main effects have been calculated.

There is a need for the development of simple analytical mathematical models of the burning of large forest areas, necessary for the assessment of the ecological consequences of the impact of the pyrogenic factor. Purpose. Develop mathematical models describing the spread of large-scale forest fires aimed at estimate the ecological consequences of the impact of the pyrogenic factor. Methods. Analytical review of research on the problem, theoretical and computational, mathematical modeling. Results. The results of the main parameters analysis of large forest areas combustion are presented. These include the area covered by the fire, the duration of the fire, the burnout time, the specific mass of combustible materials, the energy and power of combustion, the specific calorific value, the intensity of combustion, the movement speed of the combustion front, the influx of combustible materials, etc. Simple analytical mathematical models of large forest areas combustion have been established. These include the following models: a model with a constant growth rate of the fire area, a two-dimensional model, a model with sectorial movement of the combustion front, a model with a linear growth of the length of the combustion front, a model with a quadratic growth of the change rate of the fire area, and a generalized model. A new fire intensity classification has been proposed, containing 1–7 points from extremely low to extreme intensity. The maximum area covered by the fire (10–100 thousand km2), combustion energy (1–10 EJ) and combustion power (0.1–1 PW) have been estimated. Conclusions. Simple analytical mathematical models of the combustion process of large forest surface areas, which are necessary for quantitative assessment of the ecological consequences of fires, have been developed.

Soil erosion by water is the most important global environmental problem. A modern system for assessing and monitoring soil erosional degradation should be based on the use of remote sensing data. This raises the issue of correct data decoding. The article proposes a method for visual interpretation of eroded soils according to the Sentinel image obtained in the visible range. The authors give some combinations of decoding signs to determine the manifestations of linear and surface water erosion from images. The article shows possible errors in decoding the manifestations of water erosion and gives an example of assessing the erosion of the soil cover based on the results of decoding the Sentinel-2 satellite image. Moderately and heavily eroded soils are reliably distinguished, the area of which, according to the interpretation data, was 2.4% of the area of arable land in the studied territory. In the future, the obtained sample of spectral images of eroded soils can be used to develop an automated method of interpretation based on the principle of "computer vision".