Vol 54, No 9 (2018)

On the basis of the detection data on active fires from the MODIS satellite instrument in the 2000–2016 period an analysis of the characteristics of forest fires in the boreal zones of Eurasia and North America was carried out. The total number of the forest fires in the boreal zone is dominated by the fires in Northern Eurasia. At the same time, the intensity of the North American forest fires is higher on average than the intensity of the Eurasian forest fires. Along with some tendency to a reduction of the annual number of boreal fires, there are tendencies towards an increase in the intensity of the average forest fire, which are statistically significant for the North American region and for the boreal zone as a whole. The regional features of the long-term characteristics and the seasonal dependence of forest fires, as well as the regional peculiarities of the interannual variations of the fire level in the boreal forests, were discussed. A comparative analysis of the results of detection of fires by MODIS and VIIRS satellite instruments was carried out.

The smoke haze over the European part of Russia (EPR) and Belorus in July 2016 has been studied with the use of aerosol optical thickness (AOT) data measured by MODIS satellite spectrometers. The AOT maximum on the territory limited by coordinates 45°–70° N and 20°–60° E reached 2.95 on July 24, 2016 with an average regional value of 0.48. The total mass of smoke aerosol without the area covered by clouds was 0.73 million tons. Analysis of the wind fields and five-day back trajectories of air mass movement showed that the smoke was transported by the northeast winds to the EPR and Belorus from western Siberia, including the Yamalo-Nenets Autonomous District, which was characterized by large forest fires from July 17 to 23. Simulation of the radiation regime of the smoky atmosphere indicated that the average radiative forcings of smoke aerosol at upper and lower boundaries of the atmosphere for the above-mentioned territory are –29 and –54 W/m², respectively (the extreme values are –124 and –154 W/m2, respectively). A comparative analysis of the smoke haze characteristics over the EPR in July 2016 and in summer 2010 has been conducted. According to ground-based measurement data, the mass concentration of PM10 during the smoke period from July 24 to 27 in the Moscow region reached 0.25 mg/m³.

The results of comprehensive monitoring of anthropogenic impact on some coastal water areas of the Black Sea are presented. Multispectral satellite imagery and sea truth hydrooptical and hydroacoustical data acquired aboard research vessels are used as the main information sources. In the course of monitoring, more than 300 multispectral Resurs-P, GeoEye, WorldView, Landsat, Sentinel-2 and other satellite images of water areas near the cities of Sevastopol and Gelendzhik were systematized and analyzed. For processing the multispectral satellite imagery, we use an approach based on the calculation and analysis of distributions of relative variability characteristics of the backscattering signal in different regions of the electromagnetic spectrum (“color indices”). The sea truth measurements, which were carried out using a SIPO9 light attenuation index spectral meter and an ADCP acoustic Doppler profilometer, allowed us to detect submerged pollutant plumes and validate the results of satellite data processing. By using the suggested methods, we found and quantified the characteristics of intensive anthropogenic impacts due to submerged outfalls in the coastal waters near Sevastopol and Gelendzhik. Processing the multispectral satellite imagery and sea-truth data revealed several disruptions in the outfall collectors located in these coastal waters.

Sea level measurements from an absolute dynamic typography dataset for the period of 1993–2015 were used to study the variability in geostrophic circulation in the Labrador and Irminger seas. Analysis of current intensity trends calculated by geostrophic formulas has shown a weakening in cyclonic circulation observed in these two convection centers. The intensity trends are negative in all the main currents making up the Subpolar Gyre: the Labrador, East Greenland, West Greenland, and Irminger currents. On average, the negative intensity trends in the indicated currents are –0.3 cm s^–1 yr^–1, in individual areas reaching –0.5 cm s^–1 yr^–1, which corresponds to a decrease in current speed of 6.9–11.5 cm/s for the 23-year interval. Weakening of cyclonic circulation is likely predetermined by weakening convection processes and a decrease in the dome-shaped curvature of isopycnal surfaces generated by upwelling of weakly stratified water closer to the surface. This is confirmed by analysis of satellite data: in periods when deep convection weakens, the intensity of cyclonic circulation decreases at the margin of the Labrador and Irminger seas. Simultaneously with weakening currents, an increase in intensity is observed from the outer (with respect to the convection centers) margin of the considered currents, including in coastal zones.

Satellite altimetry data have been used to study water circulation in the Tatar Strait region (the northern part of the Sea of Japan) for the time period from 1993 to 2015. Seasonal and interannual variations in current velocities in the southern Tatar Strait (46°–50° N) have been found to be determined by the difference in sea level (SL) between the Korea Strait in the southern part of the Sea of Japan (Hakata station) and the northern point of the Hokkaido Island (Wakkanai station) (SL^Hakata–SL^Wakkanai). With increases in (SL^Hakata–SL^Wakkanai), the flow of the Tsushima Current into the Tatar Strait increases, the southward flow of the Primorye Current along the western boundary of the Tartar Strait decreases, and the southward flow of the West Sakhalin Current along the eastern boundary of the Tartar Strait increases. The decreased (SL^Hakata–SL^Wakkanai) leads to the formation of cyclonic water circulation in the Tatar Strait, a change in direction of the West Sakhalin Current from southward to northward, and an increase in the southwestward water transport by the Primorye Current. An increase in (SL^Hakata–SL^Wakkanai) accompanied by increased water flow through the Korea Strait leads to an increase in seawater temperatures in the northern part of the Sea of Japan.

Long-term trends in the sea surface temperature in the Canary upwelling zone and their causes are analyzed on the basis of satellite data from the 1980s until the present. It is shown that the wind activity has strengthened near the northwestern African coast during last 30 years, which is accompanied by local intensification of wind-driven upwelling. The northeastern trade wind weakens in the open Tropical Atlantic, along with the horizontal heat advection in the upper ocean layer, which leads to a decrease in the area of the upwelling waters. As a result, both tendencies partly compensate one another when the temperature is averaged over the region in the northeastern Tropical Atlantic (between 10°–30° N, 10°–25° W).

Results of an investigation into the spatiotemporal variability of the main characteristics of jet streams (JSs) in the upper troposphere of the Northern Hemisphere in the field of view of European geostationary meteorological satellites for the period 2007–2015 are presented. The JS characteristics are obtained using an automated method for calculating the horizontal wind velocity profile based on atmospheric sounding data from the SEVIRI radiometer in the 6.2-μm water vapor channel. Significant linear trends of most JS characteristics are revealed. It is shown that the relative increase in the number of JSs and their effective lifetime were 25 and 22%, respectively, and the relative decrease in the maximum wind speed on the axis and the horizontal velocity gradient on the cyclonic and anticyclonic sides were 7, 13, and 20%. The annual variation is most pronounced for the number of JSs, their maximum velocity, and average area and width. One characteristic feature is the synchronous annual variability of the maximum velocity and width of JSs determined by the isotach level V = 30 m/s. A pronounced horizontal asymmetry of the wind-velocity profile in JSs is noted. A stable annual oscillation and its harmonics are observed in amplitude spectra and waveletograms of time series of most daily and monthly mean characteristics. Significant oscillations were observed with periods of 19–23 and 37–39 days and 26.5–27.5, 35–37, and 42–45 months.

The structure of an urban heat island in the large industrial centers of the European part of Russia is studied based on the MetOp-A and MetOp-B satellite data. The intensity of the heat island is characterized by the different temperature and specific humidity between the urban area and the surrounding territory. It is shown that this analysis can be used only for large megalopolises like Moscow due to the limited horizontal resolution of the satellite data. The satellite data are grouped in time intervals of 19:30–23:30 and 10:00–13:00 UTC, called “evening” and “before noon” intervals, respectively. In the summer, Moscow’s heat island extends to ~1500 m. In the winter, the vertical extent of the heat island is ~1000 m before noon, and in the evening the heat island is recorded only in the lowest part of the profile. During the summer, the heat island is accompanied by an urban dry island that extends for a height of ~1000 m. Specific humidity increases above these heights as a rule. In the winter, a wet island is most pronounced above the surface.

Mountain massifs of the world, and high-mountain areas in particular, are barely accessible and as a result are insufficiently studied. The comparative characteristics of mountain regions differ significantly, which makes objective scientific generalizations difficult. This situation may be improved by the remote satellite investigation of these areas, which not only enables us to fill these gaps in knowledge but also creates the background for further modeling various associations of the mountain systems of other planets. Therefore the elaborated special methods of deciphering mountain regions may be successively used in future space research. The study of mountain regions by the example of areas with a combination of mountains and uplands on the Earth enables us to conclude that there is a wide diversity of combinations with particular specific features and that there is a need to reveal the structures of combinations of mountain systems with one another and with areas of the planation of the topography. The specification of active and passive margins of isolated mountain blocks for the kinetic analysis of the dynamic conditions of their formation is substantiated.

This paper presents an analysis of seasonal variations in the brightness temperature of large freshwater lakes (Baikal, Ladoga, Great Bear, and Huron) according to the data of the MIRAS radiometer of the SMOS satellite. The data show the possibility of determining the onset of the destruction of the ice cover. The resulting conclusions are confirmed by model calculations. The actual meteorological characteristics of the region and glaciological features of the studied objects were used as input parameters for the model.

We have determined the informational value of the Normalized Difference Vegetation Index (NDVI) for predictive mapping of the content of available lithium in the arable horizon of soils of different slope positions: the first (280–310 m) and the second (240–280 m) altitudinal levels. The NDVI is not informative for the diagnostics or mapping of the content of available lithium in soils of small drainage valleys, the width of which is smaller than the resolution of the satellite image (30 m). In the regression model, the NDVI explains 28% of the variation in the content of available lithium in soils. Based on this model, a predictive map of the content of available lithium in soils has been compiled. Data on the spatial distribution pattern of the NDVI calculated based on a Landsat 8 satellite image (resolution of 30 m) were used as an indicator and the cartographical basis for digital mapping. The accuracy of the prediction of the content of available lithium in soils is good (MAPE is 16.9%). It has been revealed that the NDVI values and the content of available lithium in soils of the first altitudinal level are higher than in the second. The differences between NDVI in the drainage valley and on the first altitudinal level are not insignificant.

The article describes the formation features of short- and mid-term strong (M ≥ 6) earthquake precursors detected from space. A database has been created that contains parameter variations for the ionospheric, geodynamic, and thermal fields detected from space during the preparation and occurrence of significant seismic events. This database is an important element of a unified integrated system for monitoring catastrophic natural disasters. We present a technique for the collection and systematization of satellite and related information, as well as data processing methods to obtain information on irregular variations of various geophysical fields in seismic regions. This database contains general information on more than 4000 earthquakes, as well as the characteristics of 80 strong earthquakes (magnitudes from 6.0 to 9.1) that occurred in various world regions between 1990 and 2017. We also present examples from the database of visualization and analysis of data for various precursors of an earthquake that occurred in Italy on August 24, 2016 (M = 6.2).

We report the results of the use of the World Wide Lightning Location Network data to analyze the core structure of super typhoons that occurred in the northwestern Pacific Ocean in 2012–2013. The distributions of lightning discharges are compared to the ocean-surface wind fields according to the data of the Advanced Scatterometer (ASCAT) and the infrared images of the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the MetTop-A and Aqua satellites, respectively. In the central regions of all of the studied typhoons, the structures that are fragments of circular or spiral mesometeorological-scale forms, which can be related to the presence of the cloud eyewall of typhoons, are observed even a day before the typhoon’s maximum intensity. These circular structures become completely apparent on the day of the typhoon’s maximum intensity and then begin to break down. It is shown that the position of the center of a typhoon and its traveling speed can be estimated from the distribution of lightning; in addition, the geometric characteristics of an eyewall, which are listed in reports on storms and typhoons, can be determined.

This paper considers a typical case of winter cold air invasion into the Black Sea region in January 2010. Using the WRF numerical model, the intensive convection over the sea on January 25 has been reproduced and the simulation results have been verified using satellite data on cloudiness, cloud top temperature, and specific humidity. It has been shown that, according to both the modeling results and the satellite data, mixed convection over the sea occurred but with the prevalence of cells playing the main part in the mixing in the atmospheric boundary layer (ABL). The cloud top height has been determined both by satellite data and by simulation results; it has been shown that the model reproduces the observed increase in the cloud top height over the sea with the distance from the coast. Spectral analysis of the vertical convective moisture flux fields has shown that the model correctly reproduced the horizontal size of cloud structures near the shore. It was found from the modeling results and satellite pictures that the horizontal size of convective cells over the sea increased downwind. The main components of the convective kinetic energy balance in the atmospheric boundary layer have been considered: energy generation due to pressure pulsations and work of the buoyancy force, as well as the decrease in energy due to turbulent diffusion and convective advection. It has been shown how these quantities varied with height and with the distance from the shore.

A new technique has been developed to obtain the total ozone content (TOC) under cloudy conditions from the spectra of outgoing thermal IR radiation measured by a satellite IRFS‑2 spectrometer. Analysis of the technique errors has shown that the differences between the obtained TOC and independent satellite (OMI) and ground-based (Dobson, Brewer, and M-124 instruments) measurements are usually 3–5%. The highest differences (up to 10%) are observed in the southern polar latitudes in the presence of an ozone hole over Antarctica. IRFS‑2 allowed the study of ozone miniholes over Russia in the first quarter of 2016. The measurements show an almost twofold decrease in TOC on certain days.

This paper presents an analysis of the experimental measurements of the azimuthal anisotropy of the microwave emissions of a rough water surface. The experimental data were obtained using microwave radiometers with operating frequencies of ~37 GHz (a wavelength of ~8 mm) on the oceanographic platform of the Black Sea Hydrophysical Experimental Facility of the Russian Academy of Sciences in the period from 2005 to 2016. This paper describes the azimuthal anisotropy effect, experimental studies, measurement methods, and data processing. A qualitative comparison of the measurement results with the model calculations and other experimental studies of anisotropy was performed. It was shown that there is a strong sensitivity of the variation in the radio emissions of a rough water surface, both to the wind speed and to its direction at different incidence observation angles.

In this paper, we discuss the time series of the coefficient of backscattering from forest cover and unused land in the Moscow region based on 29 C-band sessions of the Sentinel 1A satellite over a one-year period from March 10, 2015 to March 4, 2016. The data were interpreted using the MIMICS model of the change in the permittivity of the elements of the forest cover and the model of the change in the permittivity of the soil. The seasonal features of the change in backscattering from the forest using two polarizations of VV and VH are shown for the Losinyi Ostrov forest. A strong positive correlation was found between values ​​of the backscattering coefficient of the forest and values of air temperature. Using the MIMICS model, we were also able to relate the annual changes in the backscattering coefficient of the forest to changes in the permittivity of the trees dependent on temperature. The soil moisture content of unused land in the vicinity of Fryazino, Moscow Region was estimated based on the radar data for 2015–2016. Data on soil moisture can be extracted using a single equation of Dubois et al., 1995 for consistent polarization and regression of Rao et al., 2003 under a number of conditions. The time series of the values ​​of the equivalent water layer for the studied field is shown for the snow period.

In this paper, the experience of interaction of different organizations within the implementation of the technique of validation of the onboard special-purpose equipment (SPE) of the space system intended for the Earth remote sensing (SS ERS) in the radar range under conditions of full-scale operation. The results of estimation of the spatial resolution and radiometric characteristics of the equipment installed onboard TerraSAR-Х spacecraft are displayed. The data were obtained using the implemented technique based on the radar survey of specially manufactured ground test objects. The possibility of the continuous operation of the verification measurement system for the validation of characteristics set for the ERS radar facilities is shown.

This paper presents the development of a model version of a software package for analyzing the dynamics of dangerous exogenous processes in view of the assessment of natural risks. The work was performed with thermokarst processes and subsidence processes affecting linear engineering structures as examples. Software package development was based on the use of mathematical landscape morphology approaches and the corresponding mathematical models of the morphological structure. Both the expansion of existing foci and the emergence of new foci during pipeline operation were considered in the software package as causes of damage to a linear engineering structure. Decisions on the probability of damage to the structure were based on the corresponding model. The materials of repeated remote surveys served as the input data for the software package, and the probability of damage to the engineering structure within a given time was calculated as a result.

This study investigated to what extent risk estimates can be modified by involving in the process readily available space data and well-tested processing methods. We classify Landsat data for these types using the support vector algorithm and small characteristic training sites for each type. The dispersion modeling problem, unlike most classification tasks, is tolerant of unclassified areas. We show that the classification obtained is better than available global maps based on MODIS or Landsat. For a large chemical plant, we perform dispersion modeling and calculate the maximal hourly concentrations and acute risk from the main pollutant. We compare several versions of calculated risk based on the surface parameters assessed from global maps and variants of Landsat classification to show that the latter are twice as accurate as the former (with a ~20 and ~40% error, respectively). Risk estimates are shown to vary considerably (by ~25%) depending on the yearly set of Landsat data used, so that using multi-year data is a must, unless land use changes considerably over the period. Thus, in assessing the hazard from air pollution from any specific plant, which is an obligatory procedure for establishing the plant’s sanitary protection zone and obtaining the pollutant emission permit, it is desirable to use Landsat data.

The relationship between the DN/reflectance values of Landsat 5 TM, Landsat 8 OLI, and U-K‑DMC2 SLIM-6-22 imagery and the concentration of total suspended matter (TSM) in the water was determined on the basis of field turbidity measurements in 2011 and 2013. The determination coefficient R² for all of the relationships exceeds 0.84, indicating their high reliability. The average deviation of the calculated values from in-situ measurements varies from 2 to 7 mg/L (from 11 to 29% of the range of values). The most accurate model was obtained for the 2013 data, when the field turbidity measurements were most numerous (approximately 100). The concentration of suspended matter in the waters of Lake Baikal was mapped taking the effect of different penetration depths for solar radiation of different wavelengths into account. We also tested the applicability of imagery of Landsat and UK-DMC2 satellites for mapping the turbidity in the branches of the Selenga Delta and compared the results with the results of processing of high spatial resolution imagery of SPOT 6 NAOMI and experimental hyperspectral images of the ULM Headwall taken in the framework of the Leman–Baikal project.

The application of hyperspectral remote sensing of high spatial resolution is compared to conventional ground-based forest surveys on sample plots and is considered as a possible alternative to these labor-intensive works. Pattern recognition methods have become the principal approach used to solve this type of applied problems. Pattern recognition processing of hyperspectral images serves to identify different classes of objects as well as to determine their parameters, such as the net primary productivity of forests with different ages and species composition. The employed classifiers use the latest advances in forest pattern recognition based on hyperspectral images. The classification accuracy is compared to the accuracy of ground-based observations. The results indicate the promise of the proposed novel approach.

The validation of measurements of vertical temperature profiles by the IKFS-2 instrument (the Meteor-M no. 2 satellite) in cloudless conditions was based on the comparison with radiosonde measurements and data from NCEP GFS analysis. Vertical resolution matching is shown to decrease the root-mean-square (RMS) difference between the results provided by the two measurement methods by 0.2–1 K depending on the altitude in the atmosphere. When the vertical resolution is matched the absolute values of the mean differences between the satellite and the radiosonde measurements do not exceed 1 K and the mean square differences vary from 1.2 to 1.8 K, except for the surface layer, where they reach 2 K and 4 K, respectively. The RMS differences between the satellite temperature measurements and NCEP GFS data show worse agreement over the ground (up to 2 K against 1.2–1.5 K for sounders). In the 300–600 hPa pressure interval, the RMS difference between satellite and NCEP GFS data is less than 1 K over water surface but increases to 1.5–2 K over land. In the cloudless cases, the accuracy of sounding over water surface by IKFS-2 (when compared with the analysis results) approaches the accuracy displayed by IASI, which is functionally similar to IKFS-2.

The presence of cryoprecipitation, which forms a thin film on the input windows of infrared (IR) detectors and distorts the signal, is a major issue in calibration of IR channels of the multispectral scanning imager–radiometer (MSU-MR) aboard Meteor-M No. 2. A model of signal attenuation in transmission through such films and a method for calculating this attenuation were developed. Correction functions for the detected signal were obtained. The developed algorithms were used for cross-calibration between the MSU-MR IR channels and the corresponding channels of the advanced very-high-resolution radiometer of MetOp satellites. An algorithm for calculating the sea surface temperature (SST) based on the non-linear SST technology (split-window technology) was developed and verified by comparison with in situ data. The SST calculation error was less than 0.8°C for the entire sample, which satisfies world quality standards. The stability of calibration parameters within an interval of two years was demonstrated.