Near-earth Atmosphere Research Articles

ВПЛИВ ГЛОБАЛЬНОЇ СЕЙСМІЧНОЇ АКТИВНОСТІ НА ПАРАМЕТРИ ІОНОСФЕРИ ТА ПРИЗЕМНОЇ АТМОСФЕРИ

Subject and Purpose. The catastrophic magnitude of life and monetary losses associated with earthquakes spurs extensive searches for reliable earthquake precursors. It is common knowledge that lithospheric processes have a direct bearing on the state of atmosphere and ionosphere during earthquakes. However, the usual practice is to enquire things in the immediate vicinity of the hypocenter, notwithstanding the global nature of seismic processes. The present work is different as considers the changes of pressure and temperature in the near-Earth atmosphere and the total electron content (TEC) in the ionosphere for world regions at arbitrary distances from hypocenters of strong earthquakes. Methods and Methodology. Employed are the data from the maps of the ionospheric TEC and the maps of the pressure and temperature in the atmospheric surface layer in world regions of 40°N latitude. The quantitative estimates are provided by the superposed epoch analysis for winter seasons between 2012 to 2018. Days of strong earthquakes of the Richter magnitudes within 6.3 to 7.9 are taken for the "zeros" whatever the geographical coordinates of the event. Results. The near-Earth atmosphere pressure P0 shows a decrease for about 5 days before the earthquake and gets elevated for about 5 days after the event. The air temperature T behaves in the opposite way. The TEC shows a sharp increase 2 to 5 days before the earthquake. The typical deviations DP0 and DT are of up to 2 hPa and 0.3 K, respectively. The TEC deviations, DTEC, are within 3 to 4%. Where the longitudes fall on the lithosphere plate boundaries, these deviations are nearly doubled. Also, the magnitude of the effect is higher in the regions where the atmospheric pressure is lower. The established patterns indicate that the gas release from underground plays an important role in the lithosphere-atmosphere and lithosphere-ionosphere interaction effects. In this case, the main part is played by radon fluxes that initiate the near-Earth atmosphere ionization and trigger a whole chain of secon- dary processes. Conclusions. The results of the work indicate that atmospheric and ionospheric effects caused by lithospheric processes take place at arbitrary distances from strong earthquake hypocenters. Gaseous emissions from underground play an important role as a primary factor of these global effects.

Retrieval of high spatial resolution precipitable water vapor maps using heterogeneous earth observation data

The determination of the amount of precipitable water vapor (PWV) from global navigation satellite system (GNSS) is restricted to a limited number of ground-based stations with low spatial resolution. The PWV obtained by the multi-source data fusion method has a low spatial resolution because of the low spatial resolution of the data used. Therefore, it is difficult to retrieve PWV maps with sub-km resolution. Therefore, retrieving PWV with high spatial resolution becomes the focus of this study. A dual-scale method for retrieving PWV maps, based on heterogeneous earth data, is proposed, which can obtain sub-kilometer resolution PWV, while maintaining accuracy. First, an approach for analyzing the spatial correlation between land cover types (LCT) and ground-based PWV was proposed, and the meteorological, ecological, topographic, and LCT variables affecting changes in PWV in the near-earth atmosphere were determine, Subsequently, three different regression models, including multiple linear regression (MLR), random forest (RF), and a generalized regression neural network (GRNN), were used to construct the functional model linking heterogeneous earth observation data and ground-based GNSS-derived PWV. Finally, the PWV map with sub-kilometer resolution was generated based on the dual-scale method. Unlike the PWV obtained by data fusion and remote sensing technology, the proposed dual-scale retrieval method can generate PWV maps at 300 m spatial resolution. Statistical analyses demonstrated that the RMS of the PWV derived from the proposed method was less than 2.2 mm, and the bias was close to 0, thereby filling the gap in the sub-kilometer high-precision PWV products.

Practical underwater quantum key distribution based on decoy-state BB84 protocol.

Polarization encoding quantum key distribution has been proven to be a reliable method to build a secure communication system. It has already been used in an inter-city fiber channel and near-Earth atmosphere channel, leaving an underwater channel the last barrier to conquer. Here we demonstrate a decoy-state BB84 quantum key distribution system over a water channel with a compact system design for future experiments in the ocean. In the system, a multiple-intensity modulated laser module is designed to produce the light pulses of quantum states, including signal state, decoy state, and vacuum state. Classical communication and synchronization are realized by wireless optical transmission. Multiple filtering techniques and wavelength division multiplexing are further used to avoid cross talk of different lights. We test the performance of the system and obtain a final key rate of 245.6 bps with an average quantum bit error rate of 1.91% over a 2.4 m water channel, in which the channel attenuation is 16.35 dB. Numerical simulation shows that the system can tolerate up to 21.7 dB total channel loss and can still generate secure keys in 277.9 m Jerlov type I ocean channel.

ЕЛЕКТРОМАГНІТНІ ЕФЕКТИ АКУСТИКО-ГРАВІТАЦІЙНИХ ХВИЛЬ У ПРИЗЕМНІЙ АТМОСФЕРІ

Purpose: Acoustic and atmospheric gravity waves (AAGW) are generated by many natural and anthropogenic sources. The AAGW propagation at ionospheric heights is accompanied by the generation of disturbances in the magnetic and electric fields. The plasma presence plays a crucial role. The mechanisms for generating electrical and magnetic disturbances in the near-Earth atmosphere by the AAGW have been studied much worse. Therefore, the validation of the capability to generate electromagnetic disturbances in the near-Earth atmosphere by the AAGW is an urgent problem. The purpose of this paper is to describe the mechanism for generating disturbances in the electric and magnetic fields in the near-Earth atmosphere under the action of AAGW and to estimate the amplitudes of these disturbances for various AAGW sources. Design/methodology/approach: The impact of a series of highenergy sources often results in the generation of synchronous disturbances in the acoustic and geoelectric (atmospheric) fields, when an approximate proportionality between the pressure amplitude and the amplitude of the disturbances in the atmospheric electric field is observed to occur. Based on the observational data and making use of the Maxwell equations, the theoretical estimates of the disturbances in the electric and magnetic fields have been obtained. Findings: Simplified expressions have been obtained for estimating the amplitudes of the electric and magnetic fields under the action of the AAGW generated by natural and manmade sources. The amplitudes of the electric and magnetic fields generated by the AAGW of natural and manmade origin, which travel in the near-Earth atmosphere, have been calculated. The amplitudes of the AAGW generated electric and magnetic fields are shown to be large enough to be detected with the existing electrometers and fluxmeter magnetometers. The magnitudes of the amplitudes of the electric and magnetic fields generated in the near-Earth atmosphere under the action of AAGW are large enough to trigger coupling between the subsystems in the Earth–atmosphere–ionosphere–magnetosphere system. Conclusions: The estimates and not numerous observations are in good agreement. Key words: acoustic and atmospheric gravity waves, near-Earth atmosphere, volume charge, atmospheric pressure disturbances, electric field, magnetic field

Negative Electrization of the Sargasso Sea as the Cause of Its Anomaly

Due to the daily rotation of the Earth, both its surface, including water, and the atmosphere constantly cross the lines of force of the geomagnetic field. For this reason, electromagnetic forces are constantly acting both on the earth's surface and in the earth's atmosphere. These forces distribute ground and atmospheric charges in both vertical and horizontal directions. The distributive action of the earth's electromagnetic forces is manifested in the characteristic polarization of the near-earth atmosphere and clouds, as well as in the appearance of celestial electric discharges and tornadoes. It is shown here that the same forces can cause negative electrization of the Sargasso Sea. It also shows that such negative electrization can be the cause of a number of anomalous phenomena occurring in the Sargasso Sea region, including a decrease in the buoyancy of ships sailing in the Sargasso Sea and a decrease in the lift of aircraft flying over its surface. At the same time, it is proposed here to use the positive electrization of ships sailing in the Sargasso Sea and aircraft flying over its surface to increase their buoyancy and lift, respectively. It also shows in detail the mechanism due to which the negative electrization of the Sargasso Sea air reduces the metabolic rate of the human body, in general, and, in particular, of the nervous tissue, including the brain. Thus, here is the most detailed analysis of the physical and physiological reasons that determine the anomaly of the Sargasso Sea.

Study on the Scattering Effect of Terahertz Waves in Near-Surface Atmosphere

Terahertz waves suffer from scattering attenuation of various types of particles due to the complex environment in the near-surface atmosphere. This paper focused on the scattering attenuation of terahertz waves due to different kinds of particles, including droplets, haze particles, and raindrops. The optical parameters of these particles were determined by meteorological data and the related literature. The characteristics of the scattering attenuation of terahertz waves on hazy days were analyzed using Rayleigh scattering and the lognormal distribution of particles, based on different levels of pollution and frequency. The basic physical characteristics of fog were also examined to determine the influence of water content on the visibility and size distribution of droplets. The scattering characteristics of terahertz waves caused by advection fog and radiation fog were assessed using the Mie scattering theory based on the complex index of droplet refraction. Then, the characteristics of scattering attenuation in fog days were identified under different levels of visibility. The Rayleigh approximation method was used to numerically model the scattering effect of small droplets and the effect of temperature and visibility on characteristic attenuation. Results show that, by comparing the distribution of different raindrop sizes, the Joss distribution was found to be quite accurate. Raindrop size distribution and scattering attenuation characteristics under different rainfall rates were identified using the Mie scattering method. The meteorological environment is complex in the near-earth atmosphere and the scattering attenuation of terahertz waves under fog, hazy, and rainy conditions cannot be ignored. Meteorological factors, such as visibility and rainfall rate, exert critical influences on the scattering attenuation characteristics of terahertz waves.

Effect of uplink atmospheric wavefront distortion on image quality of sheared-beam imaging

Sheared-beam imaging (SBI) is a non-traditional imaging technique in which utilized are three sheared coherent lasers for illumination, and detector array to receive the intensity of speckle pattern reflected from the target. Finally the image of target can be reconstructed by computer algorithm from the data collected before. The SBI has some advantages in high resolution imaging for long-distance space targets. However, the wavefront distortion caused by atmospheric turbulence is a key factor affecting the imaging quality of SBI. Therefore, this paper focuses on the influence of wavefront distortion caused by atmospheric turbulence on the extraction of target spectral information. Theoretical model of the influence of wavefront distortion on imaging is established. The effects of low-order and high-order atmosphere turbulence on SBI imaging quality are analysed respectively. It turns out that low-order atmosphere turbulence does not result in poor image quality nor low-resolution, and just change the position of target on the image plane. But the image quality can be degraded when the wavefront root mean square (RMS) value at the target plane, caused by high-order atmosphere turbulence, exceeds /20. Beam emitted from larger aperture becomes more susceptible to perturbing effect, thus forming lower-quality wavefront. Considering that after passing through the atmosphere, beam also travels a long distance to reach the target surface. Targets at different heights will obtain different wavefront quality due to the diffraction of light. Thus the final wavefront quality is determined by turbulence intensity, aperture size and target height. Multi-layer phase-screen model and Hufnagel-Valley model are used to simulate the influences of near-earth (25 km) atmosphere on wavefront distortion at target plane with different imaging distances. Simulation results show that the wavefront RMS value rises with the increase of transmitting aperture diameter, and decreases with the increase of imaging distance. Transmitting aperture sizes in a range from 0.2 times r0 to twice r0 have been recommended for effective imaging by Hutchin[Hutchin R A 1993 Proc. SPIE 2029 161]. However, we find in our simulations that beams on the order of 2 r0 may cause significant wavefront error at short range target, and under some circumstances the clear image of target cannot be reconstructed. The imaging results of SBI at different laser transmitting apertures and different imaging distances are obtained, and evaluated by Strehl ratio. Imaging results show that choosing appropriate transmitting aperture size can effectively improve the imaging quality. But for the short-range targets, aperture size selection range presented by Hutchin can be too broad to be practicable. This paper suggests some approaches to choosing suitable aperture size for SBI system, and also providing a reference for the difference analysis of imaging quality for targets in different heights.

Hydraulic Power Engineering Under Conditions of Probable Climate Changes

Problems associated with the effect of climatic and hydrologic characteristics (temperature, precipitation, river run-off) within the Russian landmass and prediction of the performance of water-power entities under these conditions are examined. At the present time, the world's scientific community is of the common opinion that climate changes are occurring on Earth. In a paper presented by the Russian Hydrometeorolo- gic Institute (1), it is noted that "comparison of model calcu- lations with data derived from observations of the tempera- ture of the air in the near-earth atmosphere yields convincing arguments in favor of the anthropogenic nature of global warming, whereby the effect of anthropogenic activity on the temperature of the air is manifested not only in global changes, but also on a continental scale." A large part of the Russian landmass f alls within a region of significant observ- able warming. During the period from 1976 through 2006, the increase in mean annual air temperature with respect to Russia on the whole was 1.33°C for the 31 years, i.e., ex- ceeded the average warming for a 100-year period, which had ranged from 1.00 to 1.29°C. Figure 1 shows the dynam- ics of the variation in mean annual air temperature in Russia during the 20th century. It is apparent from the plot that a particularly rapid increase in temperature was observed in the past 30 - 35 years Global warming of the climate may create, and has al- ready created serious economic, political, and social prob- lems both for Russia, and also for many countries of the world. It should be pointed out that in a zone of global warm- ing, the range of temperature fluctuations also increases. Values of both extremal low, and also extremal high tempera- tures are increasing. The wind regime and moisture regime are becoming more extremal in individual regions.

Effects of solar and geomagnetic activities in variations of power spectra of electrical and meteorological parameters in the near-Earth atmosphere in Kamchatka during October 2003 solar events

We perform spectral analysis of records of meteorological (temperature, humidity, pressure of the atmosphere) and electrical (strength of quasi-static electric field and electric conductivity of air) parameters observed simultaneously at the Paratunka observatory during the solar events of October 21–31, 2003. Also, we use simultaneous records of X-ray fluxes of solar radiation, galactic cosmic rays, and the horizontal component of the geomagnetic field. We show that the power spectra of the meteorological parameters under fine weather conditions involve oscillations with a period of thermal tidal waves (T ∼ 12 and 24 h) caused by the influx of thermal radiation of the Sun. During strong solar flares and geomagnetic storm of October 29–31 with a prevailing component of T ∼ 24 h, their spectra involve an additional component of T ∼ 48 h (the period of planetary-scale waves). With the development of solar and geomagnetic activities, the power spectra of atmospheric electric conductivity and electric field stress involve components of both thermal tidal and planetary-scale waves, which vary highly by intensity. In the power spectra of galactic cosmic rays accompanying the strong solar flares, components with T ∼ 48 h were dominant with the appearance of additional (weaker by intensity) components with T ∼ 24 h. The simultaneous amplification of components with T ∼ 48 h in the power spectra of electric conductivity and electric field strength provides evidence of the fact that the lower troposphere is mainly ionized by galactic cosmic rays during strong solar flares and geomagnetic storms. The specified oscillation period with T ∼ 48 h in their spectra, as well as in the spectra of X-ray radiation of the sun, is apparently caused by the dynamics of solar and geomagnetic activities with this time scale.

Formation of the Electric Structure in the Lower Layer of the Atmosphere: Experimental Studies and Generalization of the Data

We discuss the results of field studies of the electric processes in the ground layer of the atmosphere. Vertical variations in the electric-potential gradient near the Earth’s surface along with the data of measurements of the polar electrical conductivity, the concentration of radon-220 in the atmosphere and soil gas, and meteorological parameters in the lower 3-m layer of the atmosphere are considered. Variations in the gradient of the potential in the ground layer of the atmosphere are determined by local processes of formation of a spare electric discharge. Density profiles of the total space charge are estimated in accordance with the Poisson equation on the basis of direct measurements of the electric potential. The density of the light-ion charge is calculated using the results of measurements of the polar electrical conductivity. It is found that as a rule, alternation of two or three layers of the space charge with different signs is observed along the vertical at the observation points in the 3-m atmospheric layer under consideration. The nature of the charged layers, which are observed under different conditions near the Earth’s surface, is discussed. The history of studying the formation of the electric structure in the near-Earth atmosphere extends back over several decades. Close attention to the studies of the electricity in the ground layer is stipulated by its special role in the global atmospheric electric circuit because this layer contains the region of the electric contact of the atmosphere with the Earth’s surface. Another reason that motivates interest in the properties of the ground layer is that the ground-based sensors for studying the atmospheric electricity are located in this layer. Knowledge of the basic features in the behavior of the electric characteristics is necessary for the development of methods for ground-based measurements of the atmospheric electricity, as well as for adequate interpretation of the obtained data. The proximity of the interface between two different media (the atmosphere and the Earth’s surface) is the main cause of the difficulties in the studies of electricity in the near-Earth atmosphere. First, steep gradients of physical quantities are observed in the atmosphere near the Earth’s surface, which results in intense flows of different substances. This causes significant spatio-temporal variations in the electrical parameters, which are closely related to the meteorological characteristics and one another. Second, as the conduction current passes through the interface between two heterogeneous media with the different nature of conductivity, it undergoes a jump. A result of the jump in the conduction current is accumulation of the space charge with the corresponding sign near the Earth’s surface in accordance with the current continuity equation. In its turn, this causes a perturbation in the electric field in accordance with the Poisson equation. This set of effects is known in atmospheric electricity as the electrode effect (the notion taken from

Influence of a convective generator on the diurnal behavior of the electric field strength in the near-Earth atmosphere in Kamchatka

Diurnal variations in the electric field strength, electrical conductivity, and temperature in the near-Earth atmosphere under “fair-weather” conditions at the Paratunka observatory (Kamchatka) are considered. It is shown that the morning maximum in the electric field diurnal behavior is caused by air convection in the near-surface layer. The difference in the atmospheric temperatures near the Earth’s surface and at an altitude of 25 m is chosen as a measure of the convective air flow. A high correlation of the values of the temperature difference for these altitudes with the diurnal behavior of the electric field strength is obtained.

The Atmospheric Propagation Simulation Characteristic of the Solar Blind Ultraviolet Light

In this paper, by using Monte Carlo method to study the Solar blind area in the near-Earth atmosphere ultraviolet non-line-of-sight propagation characteristics, and the use of Point to the probability method establish a rapid Monte Carlo model, this model can effectively simulate UV with complex boundary near Earth atmosphere system response function. Comparing with the single-scatter model it shows that, this model has higher accuracy and boundary processing ability. Simulation of obstacle on ultraviolet signal distribution effects, it shows that the UV signal has strong detouring ability. Different elevation on the UV signal propagation is analyzed, the simulation results are consistent with experimental results.

Problem of the nature of the sunrise effect in diurnal variations in the electric field in Kamchatka: 1. Time variations in the electric field

The effect of sunrise in time variations in the electric field in the near-Earth atmosphere at the Kamchatka Paratunka observatory has been studied. Twenty-nine records under fair-weather conditions have been selected. It has been indicated that the estimated effect parameters—the times of the effect’s onset and field strength maximum relative to the sunrise time, as well as the ratio of the strength maximum to its value before sunrise and the effect duration—coincide with the previously published data. Thereby, the conclusion is confirmed that the sunrise effect in diurnal variations in the electric field in the near-Earth atmosphere is related to the turbulence and convection processes in the atmospheric boundary layer at a change in atmospheric temperature.

Experimental investigation of the scattering of UV laser radiation in the near-earth atmosphere

This article discusses the apparatus, methodological questions, and the results of field measurements of the directed scattering index of laser radiation with wavelengths 248 and 351nm in the near-earth atmosphere.

10.1007/s11478-008-2015-2

A spectral analysis of simultaneous diurnal variations in the E z component of the quasi-static electric field in the near-Earth atmosphere, VLF radio noise, and the horizontal component of the geomagnetic field, observed at Kamchatka in September 1999, has been performed. These geophysical parameters are indirectly used to study wave processes in the near-Earth atmosphere and in the ionospheric D and dynamo regions within the band of periods of internal gravity waves (T = 0.5−3.5 h). The correlation method in the frequency region is used to analyze the interrelation between the wave processes in these atmospheric regions. The power cross-spectra of various pairs of geophysical parameters have been studied depending on meteorological, seismic, and geomagnetic activities. It is shown that the oscillations in the power spectra in the T ∼ 1–1.5 h band of periods are caused by the sources of internal gravity waves in the near-Earth atmosphere and by the remote sources above the dynamo region of the ionosphere within the T ∼ 1.5–3 h band of periods.

Power spectrum features of the near-Earth atmospheric electric field in Kamchatka

Power spectrum of the diurnal variations of the quasi-electrostatic field Ez in the near-Earth atmosphere have been presented for the first time. The Ez power spectrum variations in the period of fine weather have been shown to exhibit two bands of the periods of natural atmospheric oscillations with T = 1-5 and 6-24 h. These oscillations are the modes of the internal gravity and tidal waves in the lower atmosphere. On the days under atmospheric precipitation, the spectral power of Ez increases by an order of magnitude. During the pre-earthquake period, when the diurnal Ez variation had an anomaly, the intensity of harmonics with T = 1.8, 2.2, and 3.8 h increased by an order of magnitude or more in comparison with the Ez spectra in fine weather. Two additional spectral bands with T = 0.6 and 1 h have appeared simultaneously.

Power spectra of thermal tidal and planetary waves in the near-Earth atmosphere and in the ionospheric D region at Kamchatka

Spectral analysis of the diurnal variations in the quasi-static electric field in the near-Earth atmosphere and VLF atmospheric radio noise at a frequency of 5.3 kHz, simultaneously observed in September–October 1999 at Paratunka observatory of the Institute of Cosmophysical Research and Radiowave Propagation, has been performed. The variations in the intensities of the spectral power density and the period durations of the variations in the T ∼ 8–24 h band and higher as functions of geomagnetic and seismic activities have been studied.

Effect of the Sun shift from the center of inertia on the temperature of the troposphere

The effect of space factors on the Earth’s albedo and the near-Earth air temperature is considered. The existence of a strong statistical relation between the temperature of the near-Earth atmosphere and the calculated shift of the Sun from the Solar System center of inertia is determined. The variations in the temperature of the near-Earth atmosphere in southwestern Siberia are estimated to 2050. The dependence of solar activity on the twisting of the Sun motion trajectory has been indicated.

Physical models of coupling in the lithosphere-atmosphere-ionosphere system before earthquakes

The most important models of coupling in the lithosphere-atmosphere-ionosphere system are considered. In some of these models, it is assumed that atmospheric acoustic and acoustic gravity waves (AGWs), which propagate through the atmosphere and reach ionospheric altitudes (resulting in the generation of electric field disturbances and modulation of charged particle density), are generated in the near-Earth atmosphere over the earthquake preparation region. In other models it is assumed that ionospheric disturbances originate owing to the modification of electric fields and currents due to electric processes in the lithosphere or near-Earth atmosphere. It seems impossible to stress on only one model and reject the remaining models because the characteristic spatial scales of effects observed in the ionosphere before earthquakes vary from 200–300 km to several thousand kilometers, and the characteristic times vary from several minutes to several days. We can assume that there are several physical mechanisms by which the lithosphere-ionosphere coupling is actually implemented.

Association of the negative anomalies of the quasistatic electric field in atmosphere with Kamchatka seismicity

Abstract. One hundred three cases of a bay-like depression in the strength of the Ez component of the quasistatic electric field in the near-Earth atmosphere, observed from 1997 to 2002 on Kamchatka, have been analyzed statistically. It has been shown that the most probable length of a bay is 40–60 min. The most probable drops in Ez are minus 106–300 V/m. The dependence of these values on an earthquake class and a distance to the epicenter was not found. The probability of earthquake prediction over 24 h before an earthquake based on the Ez anomaly is 36%.