Spatial and Temporal Variations of Infrared Emissions in the Upper Atmosphere. 3. 5.3-μm Nitric Oxide Emission

The results of rocket and satellite measurements available in the literature of 5.3-μm nitric oxide emission in the upper atmosphere have been systematized and analyzed. Analytical dependences describing the height distribution of volumetric intensity of 5.3-μm emission of the NO molecule and its variations in a range of heights from 100 to 130 km as a function of the time of year, day, latitude, and solar activity have been obtained.     

Characteristics of the Energetic Electron Precipitation and Magnetospheric Conditions in 1994

The problem of the rapid depletion and saturation of the Earth’s outer radiation belt with energetic electrons is one of the central problems in the physics of the magnetosphere. The precipitation into the atmosphere and the escape of electrons from the magnetosphere are competing reasons for the depletion of the radiation belt. Long-term measurements of energetic electron precipitation (EEP) in the atmosphere in the experiment of the Lebedev Physical Institute (LPI) can be used to study the relative role of these phenomena. High fluence values of relativistic electrons in the outer belt is a necessary condition for EEP observation; however, the relation of the EEP rate to the condition of the belt is ambiguous, which is shown by the example of observations in 1994.     

Nonequilibrium Effects in Atmospheric Perturbations Caused by Solar Radiation Flux

The effects of atmospheric nonequilibrium in the generation of wave perturbations due to the solar radiation flux are studied. Equations of nonequilibrium thermodynamics are used to perform an assessment of the channels of solar energy transformation into the atmosphere for different altitudes. As a result of calculations of the dispersion relation for a nonequilibrium atmosphere, we consider how the flux of solar radiation changes the spectrum of natural atmospheric oscillations at different altitudes and for different solar activities. A qualitative relation between the results of wave spectra calculations and the data of ionosphere dynamics observations for different intensities of the solar radiation flux has been established.     

Assessment of earthquake hazard for the northwestern Vietnam from geological and geophysical data using an original program package

The highest seismic activity in Vietnam is observed in the northwest of the country, hence the practical significance of more accurate assessment of the earthquake hazard for the area. The worldwide experience of seismicity, in particular, the recent Tohoku mega-earthquake (March 11, 2011, M _w = 9.0, Japan) shows that instrumental and historical data alone are insufficient to reliably estimate earthquake hazard. This is all the more relevant in relation to Vietnam where the period of instrumental observation is short and historical evidence is nearly lacking. In this connection we made an attempt to construct maps of earthquake hazard based on known seismicity data using the available geological and geophysical data and the method of G.I. Reisner and his associates for classification of areas by seismic potential. Since the question of what geological and geophysical parameters are to be used and with what weights remains unresolved, we developed a program package to estimate Mmax based on different options in the use of geological and geophysical data. In this paper we discuss the first results and the promise held by this program package.     

A comparative analysis of the accuracy attainable for the local monitoring of Earth’s surface movements and deformation using the GPS and GLONASS navigation satellite systems

This paper is concerned with an experiment that was intended to compare the respective accuracies of local GNSS monitoring using observations by GPS and GLONASS satellites at different elevations above the horizon. We used data from continuous daily observation sessions in a local network during 3 months in the “static” mode. An analysis of parameters that characterize the accuracy and efficiency of displacement determinations showed that the combined GPS + GLONASS data processing has the highest accuracy at elevation angles greater than 15°. It is shown that the accuracy of GLONASS observations is not considerably worse than that of GPS. We note that the time-dependent variation of GLONASS observation is large.     

IRI model in the problem of predicting ionospheric radio-wave propagation under conditions of high solar activity

The paper presents the results of an analysis of the correspondence between model representations the monthly mean diurnal dependences of critical frequency and vertical profiles of plasma frequency at local noon at IZMIRAN station for the middle months of the four seasons of 2014, the year of the maximum solar activity in the current 24th cycle. It is shown that in general the IRI model reliably describes the daily variation of foF2, and the smallest discrepancy is achieved when its basic input parameter is given by the ionospheric index of solar activity IG12. An exception is April, for which there is a fundamental discrepancy with the model both in the daily variation of the critical frequency foF2 and in the N _e (h)-profile for local noon time. For this month, the inadequacy in the model representation of the vertical distribution of the electron density turned out to be very significant in the calculation of the MUF: the relative error can reach 20%. The simulation results are confirmed by data from oblique-incidence ionospheric radio sounding.     

Space Weather Forecasting and Supporting Research in the USA

In the United State, scientific research in space weather is funded by several Government Agencies including the National Science Foundation (NSF) and the National Aeronautics and Space Agency (NASA). For civilian and commercial purposes, space weather forecast is done by the Space Weather Prediction Center (SWPC) of the National Oceanic and Atmospheric Administration (NOAA). Observational data for modeling come from the network of groundbased observatories funded via various sources, as well as from the instruments on spacecraft. Numerical models used in forecast are developed in framework of individual research projects. The article provides a brief review of current state of space weather-related research and forecasting in the USA.     

Features of Microwave Radiation and Magnetographic Characteristics of Solar Active Region NOAA 12242 Before the X1.8 Flare on December 20, 2014

This paper continues the cycle of authors’ works on the detection of precursors of large flares (M5 and higher classes) in active regions (ARs) of the Sun by their microwave radiation and magnetographic characteristics. Generalization of the detected precursors of strong flares can be used to develop methods for their prediction. This paper presents an analysis of the development of NOAA AR 12242, in which an X1.8 flare occurred on December 20, 2014. The analysis is based on regular multiazimuth and multiwavelength observations with the RATAN-600 radio telescope in the range 1.65–10 cm with intensity and circular polarization analysis and data from the Solar Dynamics Observatory (SDO). It was found that a new component appeared in the AR microwave radiation two days before the X-flare. It became dominant in the AR the day before the flare and significantly decreased after the flare. The use of multiazimuth observations from RATAN-600 and observations at 1.76 cm from the Nobeyama Radioheliograph made it possible to identify the radio source that appeared before the X-flare with the site of the closest convergence of opposite polarity fields near the neutral line in the AR. It was established that the X-flare occurred 20 h after the total gradient of the magnetic field of the entire region calculated from SDO/HMI data reached its maximum value. Analysis of the evolution of the microwave source that appeared before the X-flare in AR 12242 and comparison of its parameters with the parameters of other components of the AR microwave radiation showed that the new source can be classified as neutral line associated sources (NLSs), which were repeatedly detected by the RATAN-600 and other radio telescopes 1–3 days before the large flares.     

The Role of Quasi-Transverse Propagation in Observed Polarization of Flare Loop Microwave Radiation

The ordinary mode of gyrosynchrotron radiation was identified to be predominant in some segments of flare loops in solar flares of July 19, 2012, and October 22, 2014. These events were studied by investigation of the quasi-transverse propagation effect on the observed polarization. The analysis involved reconstruction of the magnetic field topology at the linear force-free approximation based on the data of the SDO HMI space telescope and the subsequent simulation of radio emission of flare loops with the GX Simulator software package. The quasi-transverse propagation effect was established to be characteristic for both events, but its influence on the radio emission polarization at a frequency of 17 GHz was observed only in the October 22, 2014 flare.     

Spatiotemporal parameters of anomalous reflections from the ionosphere

Analysis of vertical sounding data obtained on the network of domestic stations equipped with Parus-A ionosondes has shown that anomalous reflections from the ionosphere previously detected in Moscow are observed throughout the whole mid-latitude region. It is shown that the longitudinal effect impacts the probability of the appearance of anomalous reflections. Their spatiotemporal scales are determined. The horizontal dimensions of the anomalies, as a rule, range from several tens to several hundred, possibly a thousand, kilometers. The region of altitudes at which anomalous reflections are observed extends from the E region to F2 layer. The frequency range in which they are most often recorded is from 2 to 14 MHz. The time of their existence ranges from a fraction of minutes to many hours.