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In this work, an improved approach of the pixel-based analysis of the Terra/MODIS imagery is proposed. The approach allows us to improve the accuracy in estimating characteristics of the combustion zone when detecting thermal anomalies. The investigation is carried out based on the imagery of active vegetation fires in Siberian forests by the MODIS radiometer in the spectral ranges of 3930 to 3990 and 10 780 to 11 280 μm (bands 21 and 31, respectively). It is proposed to describe the approximation of the temperature profile of the fire front using an exponential function. Using the nonuniform approximation of the temperature distribution on the surface in the vicinity of the active combustion zone allows us to determine the portion of the active pixel of the Terra/MODIS image with the given temperature excess over the background temperature in it. This improves the accuracy in extracting active combustion zones and classifying the heat release rate at the subpixel level. This approach is applicable to monitoring fire development phases in the near real time mode.

This study is based on the processing of satellite imagery in the wave range 3.93–3.99 μm (Terra/Modis satellite) and numerical simulation results. It has been found for combustion conditions in Siberian forests that the observed fire radiative power (FRP) is 15% of the total fire power. Variations between 10 and 30% depend on both the fire development scenario (specific burnup rate of 0.01–0.1 kg/m2 s and fire front velocity of 0.01–0.1 m/s) and the conditions for remote imaging. Instrumental estimates for the ratio of fire areas by given intensity quantiles for Siberian forests are presented. The share of low-, medium-, and high-intensity fires is 41.2–58.9, 35.0–46.5, and 6.10–13.44% of the total area. Refined estimates of fire emissions have been obtained taking into account the amount of biomass burnt and variable burning intensity. The proposed method allows the mass of burned forest fuel materials (FFM) and direct fire emissions to be estimated quantitatively at a level 14–21% lower than the values calculated with the help of standard approaches. The estimates of direct carbon emissions in the given time interval of 2002–2016 were 83 ± 21 Tg/year on average, which is 17% lower than the value 112 ±25 Tg/year obtained with the standard method.

The article considers the influence of the relief, river, and urban development on the formation of vortex structures in the atmosphere and the spread of pollutants in the city of Krasnoyarsk in winter. The weak influence of urban development on the appearance of large vortex structures over the river is shown. However, in the ground layer, it significantly changes the flow pattern and determines the character of the distribution of pollutants.

In this paper, a comprehensive analysis of the interaction of the urban environment elements with the natural environment components is carried out. The assessment of the complex impact of meteorological parameters on the human body is analyzed based on data obtained from monitoring stations. The readings of monitoring stations concerning both wind speed and directions are found to significantly deviate in different parts of the city due to urban development. A numerical study of the neighborhood with the monitoring station also shows a very complex mechanism for determining the pollution intensity of the area and the relevance of the data obtained, especially concerning pollutants.

The paper presents the numerical simulation of the distribution of pollutants in winter in the atmosphere of Krasnoyarsk city. The source of the pollution is the suburban areas of the city of Krasnoyarsk, in which coal stove heating prevails. A micro-scale mathematical model based on the solution of the system of non-stationary Reynolds equations is used for modeling. The influence of various factors, such as elements of terrain and urban development, on the distribution of pollutants is studied in the paper.

The paper reveals the capabilities of SigmaFlow CFD code to predict wind conditions in terms of pedestrian comfort as illustrated by a model problem. The proposed numerical model was verified by comparing with experimental data. A group of buildings consisting of low-rise buildings and a high-rise building was considered. A comparative analysis of five computational variants with different grid saturation was performed. The results of mathematical modeling allow observing the vortex flow structure that is generated when streamlining buildings.

This article presents the results of numerical modeling of wind flows around a microdistrict. The distribution of suspended solids of 50 and 100 microns in urban environments is considered. The characteristic of urban development in terms of a comfortable stay of people is given.

The article analyzes the environmental situation in the city of Krasnoyarsk based on data of the Ministry of Natural Resources and the Ministry of Ecology and Environmental Management of the Krasnoyarsk Territory. The influence of the non-freezing Yenisei River on the movement of air masses over the city is considered based on numerical simulation. The obtained results demonstrate the ability to quickly simulate the wind pattern of the city, taking into account the heterogeneous nature of the terrain, heat transfer, wind load, and the influence of the river.

The possibility of developing power and transport systems for space applications is examined. It is suggested to use an MHD generator utilizing inhomogeneous gas-plasma flows of inert gas as the source of electric energy in such systems. The plasma of the current layers may be in the state of “frozen ionization,” when the degree of ionization exceeds the equilibrium level thereby providing for an effective MHD interaction with the enthalpy extraction coefficient of 0.4 and adiabatic efficiency of 0.8. Such a plasma is stable with respect to dissipative instabilities (ionization and overheating) and retains its positive properties at a stagnation pressure of the order of 1 MPa. The estimation of the mass-and-size characteristics of a closed-cycle solar MHD facility for space applications reveals that the specific power of the facility may amount to 500 W/kg. It is suggested that the propulsion unit should be provided by an electric rocket engine on the basis of an MHD accelerator, with the working medium provided by a nonuniform gas-plasma flow in which azimuthal plasma rings (T-layers) are inductively connected to the electric energy source. In a flow with T-layers, an efflux velocity of the order of 40 km/s is attained. With a mass flow rate of 50 g/s, the engine may develop a propulsive force of 2000 N.