The transformation of a subnanosecond ultrawideband electromagnetic pulse (UWB EMP) in a large-volume transparent plasma has been demonstrated experimentally using a large-scale KROT plasma device. ...The column of the plasma generated in the device chamber has a length of more than 4 m and a diameter of more than 1 m. This allows one to implement the regime of quasiuniform ionization, which is necessary to simulate UWB EMP propagation through the ionosphere. It is shown that the length of the wave propagation path in the plasma is sufficient for dispersion transformation of the pulse retaining the envelope of its frequency spectrum.
Abstract
The meteorological conditions in which organogenesis stages take place and hydrothermal regime can determine the phenotypic manifestation of quantitative signs, such as, for example, the ...activity of alpha-amylase. The purpose of our work was to determine what factors (temperature, precipitation, heterothermal coefficient) affect the enzyme activity, at what time of the vegetation, and in what way this influence is evident. The analysis of weather conditions and falling number (FN) for the period from 2011 to 2020 was carried out. Analysis of the FN value over 10 years showed that it can vary from 90 s to 429 s, and at that, the nature of its change is the same, regardless of whether we are considering one variety or the average value for a group of varieties. The correlation coefficient between the FN of a group of varieties and individual FN is 0.94-0.98. Generally, during the vegetation season, the alpha-amylase activity was influenced to a greater extent by the amount of precipitation than by temperature. This dependence is negative - an increase in precipitation leads to a decrease in the FN, and, consequently, to an increase in the enzyme activity. However, it was found that in different phases of ontogeny the influence of temperature and precipitation can be diametrically opposite.
The article presents results of analysis of the relationships between forest-stand parameters (age, height, growing stock volume) and
Sentinel‑2
spectral reflectance in the Central Russian ...forest–steppe. The age of oak forests is inversely related to the reflectance in all spectral ranges. The strongest relationship between age and spectral response was found in the red and short wave infrared (SWIR) bands. The relationships between forest age and reflectance in all
Sentinel‑2
bands are curvilinear and are most reliably approximated by a logarithmic curve. The height and growing stock volume of oak forests are also in inverse, curvilinear dependence with spectral reflectance in all ranges. The relationship of the height of oak forests with the spectral response is stronger than with the age of the stand. Ash-dominated forests and oak-dominated forests are characterized by similar relationships between age, forest height, and spectral reflectance. For the ages and heights of forests dominated by ash, the strongest relationship with the spectral reflectance values was also found for the
Sentinel‑2
SWIR bands.
Results of assessment are presented for the relationship between the forest cover of small dry valleys and their spectral response through analysis of object data in the forest–steppe natural zone of ...the Central Chernozem region of Russia. The SWIR reflectance of small dry valleys is shown to be tightly correlated with the percentage of forest cover. The greater the forest cover, the lower the SWIR reflectance. A logistical dependence can be used to obtain spectral-response estimates for forest cover in the SWIR range. Spectral-response estimates are found for the forest cover of small dry valleys in the Central Russian forest steppe from
Landsat
data in the mid-1980s, early 2000s, and late 2010s. Recent decades have seen an increase in the forest-cover percentage of small dry valleys throughout most of the region. From the mid-1980s to 2018, the forest cover increased from 16 to 45%. During the study period, an increase is observed in intraregional differences in the forest cover of ravines. Currently, this indicator varies more significantly within the region than in the mid-1980s.
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