MODELING A DECAMETER RADIO LINK IN PREDICTING THE RELIABILITY OF COMMUNICATION

Представлено краткое описание последовательности расчета надежности связи в декаметровом диапазоне волн, включающее в себя ряд методик и моделей определения характеристик условий распространения радиоволн и технических параметров элементов радиолинии. Особенностью предлагаемой модели декаметровой радиолинии является системное построение методик и алгоритмов определения параметров радиолинии для единой задачи прогнозирования условий радиосвязи, имеющей целью создание адаптивной радиолинии нового типа - с учетом параметров изменений геомагнитной возмущенности. A brief description of the sequence of calculation of communication reliability in the decameter wave range is presented. It includes several methods and models for determining the characteristics of radio wave propagation conditions and technical parameters of radio link elements. A feature of the proposed decameter radio line model is the system construction of methods and algorithms for determining radio line parameters for a single problem of predicting radio communication conditions, which aims to create an adaptive radio line of a new type - taking into account the parameters of changes in a geomagnetic disturbance.

Fusion of wildlife tracking and satellite geomagnetic data for the study of animal migration

Background Migratory animals use information from the Earth’s magnetic field on their journeys. Geomagnetic navigation has been observed across many taxa, but how animals use geomagnetic information to find their way is still relatively unknown. Most migration studies use a static representation of geomagnetic field and do not consider its temporal variation. However, short-term temporal perturbations may affect how animals respond - to understand this phenomenon, we need to obtain fine resolution accurate geomagnetic measurements at the location and time of the animal. Satellite geomagnetic measurements provide a potential to create such accurate measurements, yet have not been used yet for exploration of animal migration. Methods We develop a new tool for data fusion of satellite geomagnetic data (from the European Space Agency’s Swarm constellation) with animal tracking data using a spatio-temporal interpolation approach. We assess accuracy of the fusion through a comparison with calibrated terrestrial measurements from the International Real-time Magnetic Observatory Network (INTERMAGNET). We fit a generalized linear model (GLM) to assess how the absolute error of annotated geomagnetic intensity varies with interpolation parameters and with the local geomagnetic disturbance. Results We find that the average absolute error of intensity is − 21.6 nT (95% CI [− 22.26555, − 20.96664]), which is at the lower range of the intensity that animals can sense. The main predictor of error is the level of geomagnetic disturbance, given by the Kp index (indicating the presence of a geomagnetic storm). Since storm level disturbances are rare, this means that our tool is suitable for studies of animal geomagnetic navigation. Caution should be taken with data obtained during geomagnetically disturbed days due to rapid and localised changes of the field which may not be adequately captured. Conclusions By using our new tool, ecologists will be able to, for the first time, access accurate real-time satellite geomagnetic data at the location and time of each tracked animal, without having to start new tracking studies with specialised magnetic sensors. This opens a new and exciting possibility for large multi-species studies that will search for general migratory responses to geomagnetic cues. The tool therefore has a potential to uncover new knowledge about geomagnetic navigation and help resolve long-standing debates.

INFLUENCE OF GEOMAGNETIC DISTURBANCE ON THE PSYCHOLOGICALSTATE OFTHEINHABITANTS OFTHE N

The aim of the work was to determine the influence of geomagnetic disturbance on the psychoemotional status of residents of polar and Subpolar latitudes. Materials and methods. 44 male and female volunteers with an average age of 49.2 (41.7; 55.4) years, living in auroral and sub – auroral latitudes were examined using tests of Ch. Spielberger-Yu. Hanin, E. Khaimah and psychosomatic techniques. The daily CR index (Computed Radiography) was used as an integral indicator of geomagnetic disturbance. Results. The volunteers were divided into two groups: psychologically sensitive to changes in space weather (I) and-not having such sensitivity (II) (based on the presence or absence of certain coincidences of the peak values of reactive anxiety and the CR index). The groups had an equal number of persons. It was found that the most problematic area of stress-overcoming behavior in both groups was behavioral, the most effective for group I — cognitive, for group II — emotional sphere. Individuals with psychological sensitivity to geomagnetic disturbances were significantly more anxious than those who did not have this sensitivity. Conclusion. Thus, despite the fact that all the inhabitants of the Northern latitudes observed by us were not sufficiently effective in constructing the actual stressovercoming behavior, the risk of developing psychosomatic diseases was higher in the owners of psychological sensitivity to geomagnetic disturbance, taking into account their tendency to suppress emotions and significantly higher anxiety.

Predicting geo-effectiveness of CMEs with EUHFORIA coupled to OpenGGCM

<div> <p>The <strong>EU</strong>ropean <strong>H</strong>eliospheric <strong>FOR</strong>ecasting <strong>I</strong>nformation <strong>A</strong>sset (<strong>EUHFORIA</strong>, Pomoell and Poedts, 2018) is a physics-based heliospheric and CME propagation model designed for space weather forecasting. Although EUHFORIA can predict the solar wind plasma and magnetic field parameters at Earth, it is not designed to evaluate indices like Disturbance-storm-time (Dst) or Auroral Electrojet (AE) that quantify the impact of the magnetized plasma encounters on Earth’s magnetosphere. To overcome this limitation, we coupled EUHFORIA with <strong>Open</strong> <strong>G</strong>eospace <strong>G</strong>eneral <strong>C</strong>irculation <strong>M</strong>odel (<strong>OpenGGCM</strong>, Raeder et al, 1996) which is a magnetohydrodynamic model of Earth’s magnetosphere. In this coupling, OpenGGCM takes the solar wind and interplanetary magnetic field obtained from EUHFORIA simulation as input to produce the magnetospheric and ionospheric parameters of Earth. We perform test runs to validate the coupling with real CME events modelled using flux rope models like Spheromak and FRi3D. We compare these simulation results with the indices obtained from OpenGGCM simulations driven by the measured solar wind data from spacecrafts like WIND. We further discuss how the choice of CME model and observationally constrained parameters influences the input parameters, and hence the geomagnetic disturbance indices estimated by OpenGGCM. We highlight limitations of the coupling and suggest improvements for future work. </p> </div>

Deep Neural Networks With Convolutional and LSTM Layers for SYM-H and ASY-H Forecasting

<p>Geomagnetic indices quantify the disturbance caused by the solar activity in particular regions of the Earth. Among them, the SYM-H and ASY-H indices represent the (longitudinally) symmetric and asymmetric geomagnetic disturbance of the horizontal component of the magnetic field at mid-latitude with a 1-minute resolution. Their resolution, along with their relation to the solar wind parameters, makes the forecasting of the geomagnetic indices a problem that can be addressed through the use of Deep Learning, particularly using Deep Neural Networks (DNN). In this work, we present two DNNs developed to forecast the SYM-H and ASY-H indices. Both networks have been trained using solar wind data from the last two solar cycles and they are able to accurately forecast the indices two hours in advance, considering the solar wind and indices values for the previous 16 hours. The evaluation of both networks reveals a great precision for the forecasting, including good predictions for large storms that occurred during the solar cycle 23.</p>

Transient cusp ionospheric disturbances caused by a solar wind dynamic pressure enhancement

<p>Interplanetary (IP) shock driven sudden compression produces disturbances in the polar ionosphere. Various studies have investigated the effects of IP shock using imagers and radars. However, very few studies have reported the plasma flow reversal and a sudden vertical plasma drift motion following a CME driven IP shock. We report on the cusp ionospheric features following an IP shock impingement on 16 June 2012, using SuperDARN radar and digisonde from the Antarctic Zhongshan Station (ZHO). SuperDARN ZHO radar observed instant strong plasma flow reversal during the IP shock driven sudden impulse (SI) with a suppression in the number of backscatter echoes. Besides, we also report on a “Doppler Impulse” phenomenon, an instant and brief downward plasma motion, were observed by the digisonde in response to the SI and discuss the possible physical causes. Geomagnetic disturbance and convection patterns indicate the flow reversal was generated by the downward field-aligned current (FAC). We speculate that sudden enhancement in ionization associated with SI is responsible for generating the Doppler Impulse phenomenon.</p>

High-latitude crochet (Solar flare effect) as a trigger of pseud-substorm onset

<p>Solar flares are known to enhance the ionospheric electron density and thus influence the electric currents in the D- and E-region.  The geomagnetic disturbance caused by this current system is called a "crochet" or "SFE (solar flare effect)".  Crochets are observed at dayside low-latitudes with a peak near the subsolar region ("subsolar crochet"), in the nightside high-latitude auroral region with a peak where the geomagnetic disturbance pre-exists during solar illumination ("auroral crochet"), and in the cusp ("cusp crochet").  In addition, we recently found a new type of crochet on the dayside ionospheric current at high latitudes (European sector 70-75 geographic latitude/67-72 geomagnetic latitude) independent from the other crochets.  The new crochet is much more intense and longer in duration than the subsolar crochet and is detected even in AU index for about half the >X2 flares despite the unfavorable latitudinal coverage of the AE stations (~65 geomagnetic latitude) to detect this new crochet (Yamauchi et al., 2020).  </p><p>The signature is sometime s seen in AL, causing the crochet signature convoluting with substorms.  From a theoretical viewpoint, X-flares that enhances the ionospheric conductivity may influence the substorm activity, like the auroral crochet.  To understand the substorm-crochet relation in the dayside, we examined SuperMAG data for cases when the onset of the substorm-like AL (SML) behavior coincides with the crochet.  We commonly found a large counter-clockwise ∆B vortex centered at 13-15 LT, causing an AU peak during late afternoon and an AL peak near noon at higher latitudes than the high-latitude crochet.  In addition, we could recognize a clockwise ∆B vortex in the prenoon sector, causing another poleward ∆B, but this signature is not as clear as the afternoon vortex.  With such strong vortex features, it becomes similar to substorms except for its local time.  In some cases, the vortex expends to the nightside sector, where and when nightside onset starts, suggesting triggering of onset.  Thus, the crochet may behave like pseudo-onset at different latitude than midnight substorms, and may even trigger substorm onset.</p>