Forecasting Fire Risk in Forest Ecosystems Using Solar Activity Index

Improving forest ecosystems protection management based on a long-term fire hazard forecasting has been studied. Fires long-term dynamics in terms of quantity in various forests has been investigated. Fire risk patterns in forest ecosystems have been established conditional to regional characteristics due to solar period. Fire dynamics and solar periods analytics over multi-year period of time have brought to light that conditions contributing to a high fire frequency in Leningrad and Tver regional forest ecosystems arise in years with maximum and minimum solar activity. A long-term forecast of high forest fire danger periods for the next solar cycle has been performed through parameters of solar activity – Wolf numbers.

The Effect of Atmospheric Drag Force on the Elements of Low Earth Orbital Satellites at Minimum Solar Activity

Researching and modeling perturbations is essential in astrodynamics because it gives information on the deviations from the satellite's normal, idealized, or unperturbed motion. Examined the impact of non-conservative atmospheric drag and orbital elements of low-earth-orbit satellites under low solar activity. The study is consisting of parts, the first looks at the effects of atmospheric drag on LEO satellites different area to mass ratios, and the second looks at different inclination values. Modeling the impacts of perturbation is included in each section, and the final portion determines the effects of atmospheric drag at various node values. The simulation was run using the Celestial Mechanics software system's SATORB module (Beutler, 2005), which solves the perturbation equations via numerical integration. The findings were examined using Matlab 2012. Conclusion that the impacts are stronger for retrograde orbits, which is due to the fact that the satellite moves in the opposite direction. The atmospheric drag effects for all orbital elements were increased by increasing the area to mass ratio. When the node value rises, the size parameter changes slightly, but the other orbital elements change. At varying inclinations, it is found that the changes in orbital elements due to atmospheric drug.

Seasonal behavior of H component during solar cycle 24

<p>In this work we will show the behavior of the horizontal component H of the Earth Magnetic Field (EMF) along the seasons during the period of solar cycle 24 lasting from 2009 to 2019. By means of  continuous measurements of geomagnetic components (X, Y) of the EMF, we compute the horizontal component H at the Earth’s surface. The data are recorded with a time resolution of one minute at Tamanrasset observatory in Algeria at the geographical coordinates of 22.79° North and 5.53° East. These data are available from the INTERMAGNET network. We find that the variation in amplitude of the hourly average of H component at low latitude changes from a season to another and it is greater at the maximum solar activity than at the minimum solar activity.</p><p><strong>Keywords:</strong> Solar cycle 24, Season, Horizontal component H. </p>

Integrity investigation of global ionospheric TEC maps for high-precision positioning

Aside from the ionospheric total electron content (TEC) information, root-mean-square (RMS) maps are also provided as the standard deviations of the corresponding TEC errors in global ionospheric maps (GIMs). As the RMS maps are commonly used as the accuracy indicator of GIMs to optimize the stochastic model of precise point positioning algorithms, it is of crucial importance to investigate the reliability of RMS maps involved in GIMs of different Ionospheric Associated Analysis Centers (IAACs) of the International GNSS Service (IGS), i.e., the integrity of GIMs. We indirectly analyzed the reliability of RMS maps by comparing the actual error of the differential STEC (dSTEC) with the RMS of the dSTEC derived from the RMS maps. With this method, the integrity of seven rapid IGS GIMs (UQRG, CORG, JPRG, WHRG, EHRG, EMRG, and IGRG) and six final GIMs (UPCG, CODG, JPLG, WHUG, ESAG and IGSG) was examined under the maximum and minimum solar activity conditions as well as the geomagnetic storm period. The results reveal that the reliability of the RMS maps is significantly different for the GIMs from different IAACs. Among these GIMs, the values in the RMS maps of UQRG are large, which can be used as ionospheric protection level, while the RMS values in EHRG and ESAG are significantly lower than the realistic RMS. The rapid and final GIMs from CODE, JPL and WHU provide quite reasonable RMS maps. The bounding performance of RMS maps can be influenced by the location of the stations, while the influence of solar activity and the geomagnetic storm is not obvious.

Attenuation of Earth’s radiation belt electrons with protective shields based on composite W-Cu

For decreasing the radiation effects of the cosmic environment on the electronic components of spacecraft, local protection shields are used. They are manufactured on the basis of materials with high density and large atomic numbers (tungsten, tantalum, the W-Cu composite etc.) and then integrated into the ceramic-and-metal package of electronic components with an insufficient level of radiation resistance. On the basis of the Monte Carlo approach we considered the methods of decreasing the level of the dose absorbed by the crystals of active elements if using the radiation shields based on the W-Cu composite in hybrid metal cases under the action of electrons of a circular orbit with an inclination angle of 30° and an altitude of 8000 km. The electron spectra at the maximum and minimum solar activity were obtained using OMERE 5.3 software. It was established that an increase in the mass thickness of the base and cover of cases with shields up to 1.67 g / cm2 makes it possible to reduce the dose load by 3.5–3.7 times at the minimum and by 3.9–4.1 times at the maximum of solar activity. The optimization of protection by lowering the upper layer of the W-Cu composite to the base to a height of 1.2 mm reduces the absorbed dose by 6.8–9.3 times at the minimum and by 7.6–10.7 times at the maximum solar activity.

Transformation of the characteristics of quasi-biennial oscillation in a new version of the series of Wolf (relative sunspot) numbers

With the introduction from June 2015 of a new methodology for estimation of Wolf numbers W (or WSN — Wolf sunspot number), this series was corrected from January 1749 to May 2015, i.e. a new version of the series WSN was proposed. The greatest transformation affected the cycles of a statistically reliable part of the series (since, 1849), which was clearly reflected in their amplitude correction and, accordingly, in the long-period component of the series, determining the epoch of maximum/minimum solar activity. The quasi-biennial oscillations available in the solar magnetic field and in the total flux of its radiation also manifest themselves in a number of parameters of the Earth ionosphere and evaluation of their transformation degree is of high significance. This paper compares the characteristics of the frequency interval of the quasi-biennial oscillations of both versions of a series.

COMPARISON OF DIURNAL AND SEASONAL VARIABILITY OF THE CRITICAL FREQUENCY OF THE F2 LAYER OVER ILORIN, JICAMARCA AND OKINAWA DURING MINIMUM SOLAR ACTIVITY

The ionosphere displays a wide range of variations ranging from diurnal, seasonal, annual and solar cycle variation. In this paper we present a study of the comparison of diurnal, seasonal and semiannual variation of the variability (VR) of the critical frequency of the F2 layer (foF2) over Ilorin (Lat. 8.47oN, 4.6oE, dip 4.1oS) in the African sector, Jicamarca (Lat. 11.9oS, Long.76.8oW, dip 1oN) in the American sector and Okinawa (26.3oN, 127.8oE, dip 36.8oN) in the Asian sector during solar minimum period. These stations lie within the equatorial anomaly region of the ionosphere. Diurnal analysis revealed that the critical frequency of the F2 layer is more prone to variability (VR) during the nighttime than the day time at these stations, with two characteristics peaks, post-midnight peak and pre-midnight peak. The peaks at Ilorin (20 - 43%; 16 - 25%) are observed to be higher in values than those at Jicamarca (17 - 27%; 15 - 22%) and Okinawa (22 – 39%; 15 - 30%). Seasonally, December solstice maximum was noticed at Ilorin. Semiannual analysis showed that foF2 VR is highest at Ilorin station, followed by Okinawa station and least by Jicamarca station during the nighttime. Diurnal curves of Mean foF2 revealed pre-noon and post-noon peaks at all stations, with Jicamarca having highest values for both peaks while the semiannual curves of mean foF2 values showed almost equal values for all stations. Overall, foF2 variability is highest at Ilorin and lowest at Jicamarca while for F2 layer ionization the reverse is the case.