Influence Of Solar Activity Research Articles

The Possible Effect of Space Weather Factors on Various Physiological Systems of the Human Organism

A systematic review of heliobiological studies of the last 25 years devoted to the study of the potential influence of space weather factors on human health and well-being was carried out. We proposed three criteria (coordinates), according to which the work on solar–biospheric relations was systematized: the time scale of data sampling (years, days, hours, minutes); the level of organization of the biological system under study (population, group, individual, body system); and the degree of system response (norm, adaptation, failure of adaptation (illness), disaster (death)). This systematic review demonstrates that three parameters mentioned above are closely related in the existing heliobiological studies: the larger the selected time scale, the higher the level of estimated biological system organization and the stronger the potential response degree is. The long-term studies are devoted to the possible influence of solar activity on population disasters, i.e., significant increases in morbidity and mortality. On a daily scale, a probable effect of geomagnetic storms and other space weather events on short-term local outbreaks of morbidity is shown as well as on cases of deterioration in people functional state. On an intraday scale, in the regular functioning mode, the heart and brain rhythms of healthy people turn to be synchronized with geomagnetic field variations in some frequency ranges, which apparently is the necessary organism’s existence element. The applicability of different space weather indices at different data sampling rates, the need to take into account the contribution of meteorological factors, and the prospects for an individual approach in heliobiology are discussed. The modern important results of experiments on modeling the action of magnetic storms in laboratory conditions and the substantiation of possible theoreical mechanisms are described. These results provide an experimental and theoretical basis for studies of possible connections of space weather and human health.

Contribution to the Research of the Effects of Etna Volcano Activity on the Features of the Ionospheric Total Electron Content Behaviour

This research represents a contribution to the theory on the coupling of the volcanic activity and the ionospheric dynamics, represented by total electron content (TEC) patterns and their behaviour. The ionospheric response to the activity of the Etna volcano has been analysed using global navigation satellite system (GNSS)-derived TEC values, employing data from International GNSS Service (IGS) reference station near the volcano and on two distant IGS locations. Volcanic activity has been modelled using volcanic radiative power (VRP) data obtained by the Middle InfraRed Observation of Volcanic Activity (MIROVA) system. The estimated minimal night TEC values have been averaged over defined index days of the VRP increase. During the analysed period of 19 years, the volcano activity was categorised according to pre-defined criteria. The influence of current space weather and short-term solar activity on TEC near the volcano was systematically minimised. The results showed mean/median TEC increases of approximately +3 standard deviations from the overall mean values, with peak values placed approximately 5 days before the VRP increase and followed by general TEC depletion around the time of the actual volcanic activity increase. Additionally, TEC oscillation pattern was found over the volcano site with a half-period of 6.25 days. The main interpretation of results indicates that the volcanic activity has modified the ionospheric dynamics within the nearby ionospheric region before the actual VRP increase, and that the residual impact in the volcano’s surrounding area refers to terrestrial endogenous processes and air–earth currents. Those changes can be detected during criteria predefined in the research: during quiet space weather conditions, observing night-time TEC values and within the limits of low short-term solar influence.

Influence of solar activity on ambient dose equivalent H*(10) measured with thermoluminescent dosimeters in Slovenia

Ambient dose equivalent H *(10) is measured to assess general population exposure to ionising radiation. From its spatial and time variations it is possible to identify sources of exposure. In Slovenia, semi-annual H *(10) is measured routinely with thermoluminescence dosimeters at 66 locations around the Nuclear Power Plant (NPP) Krško and at 50 other locations covering the rest of Slovenian territory. Since the Chernobyl accident contamination had ceased to contribute to ambient dose equivalents, we have been calculating correlation coefficients between annual mean number of sunspots and annual H *(10). These correlation coefficients were calculated for five locations in western Slovenia and for five annual H *(10) extracted from measurements around NPP Krško. Their ranges between –0.64 and –0.38 suggest a clear negative correlation between solar activity and H *(10). Mean annual H *(10) averted by solar activity in the past two solar maxima reached 0.070 mSv around NPP Krško (155 m.a.s.l.) and 0.132 mSv and 0.180 mSv at Kredarica (2515 m.a.s.l.). Quantifying the influence of the solar activity on the ambient dose equivalent helps us to better understand exposure of the general population to ionising radiation.

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.

The influence of solar activity on the formation of plant phytomass in dry steppe conditions

The main mechanism for the formation of yield is the process of transpiration, the driving force of which is the radiation balance and photosynthetically active radiation (PAR). The larger the area of the plant surface that receives the luminous flux of solar energy, the more active the action of the photosynthetic process. The formation of organic matter depends on the formed aboveground phytomass of plants. The aim of the study is to find the optimal ratio between the emitted flux of solar energy and the area of the assimilation apparatus for further determining the phytoproductivity of plants. The object is located in the steppe zone of the central part of the Volgograd region (southern part of the Volga Upland, 48°38′52″ N, 44°26′14″ E). Modern methods of mathematical processing of experimental data were applied. The duration of the growing season of plants and the amount of light exposure affect the optical density coefficient (Kod). As a result, the coefficient (KPAR ) should be close to 1 unit for use 2.5% sunlight radiation (PAR).

ON THE CHARACTER OF AN ARTIFICIAL SATELLITE DRAG UNDER VARIOUS STATES OF SOLAR AND GEOMAGNETIC ACTIVITY

Purpose: The artificial satellites drag in the atmosphere remains an urgent problem to date. In this work, the artificial satellites data are used in order to study the atmosphere state under various manifestations of solar and geomagnetic activity. The selected satelites were moving uncontrollable being good indicators of the upper atmosphere state. The B-star (drag term) drag coefficient is used in this work. This term is used in the SGP and SDP models to take into account the resistance of the atmosphere to the satelite orbital motion. The data of the drag of two artificial satellites, one moving in elliptical and the other in circular orbits at midlatitudes (orbital plane angles of 58°-60°) were considered. These data include the end of the 23rd solar activity cycle, as well as the growth, the maximum and the decay phases of the 24th solar cycle (years 2005–2017). Seven periods of anomalous drag of the satellites were analyzed. They are: 4 monthly periods (two in 2005 and two in 2011) and 3 yearly periods (within 19.07.2014 to 22.08.2015), five-year long (2005–2010) and six-year long (2011–2017) periods. Design/methodology/approach: The periodogram analysis was made. This allowed to reveal the periodic processes in changes in the state of the atmosphere of different duration. The correlation coefficients of the B-star drag term with the indices of solar and geomagnetic activity were calculated. The analysis of extreme drag of the satellites in the periods of the increased solar and geomagnetic activity (intervals of observation lasting a month) was made. Findings: Using the solar and geomagnetic data we found that some month-long part of the anomalous drag periods were followed by flares on the Sun and the arrival of the coronal mass ejections into the near-Earth space. At time intervals of yearlong observations the highest values (0.5-0.7) were obtained for the coefficients of the B-star parameter correlation with the solar activity indices – solar radiation at the wavelength of 10.7 cm, F10.7, and Lyman alpha radiation, Lα. At monthly time intervals, the largest values of the correlation coefficients were obtained for the B-stars with the electron fluxes with energies above 0.6 and 2 MeV, E, (0.3-0.5), the Lyman alpha radiation, Lα, (0.58–0.73 for a сircular orbit satellite), and the solar constant, TSI, (0.3–0.6), as well as the geomagnetic storms intensity index, Dst , (0.66–0.69). Periodogram calculations show the presence of a whole spectrum of periods in the deceleration of a circular orbit satellite and a dedicated period for an elliptical orbit satellite. Conclusions: The B-star drag term dependences on the indices of solar and geomagnetic activity during some periods of their intensification for the 23–24 cycles of solar activity are considered. The periodogram analysis made together with the analysis of the conditions and parameters of space weather allows to see the general and more detailed picture of the solar and geomagnetic activity influence on the change in the motion of the satellite in the atmosphere. The B-star drag term helps to consider only the atmosphere influence on the artificial satellite movement in the near-Earth space. Key words: artificial satellite, atmosphere, artificial satellite drag, solar activity, geomagnetic activity, space weather

A Flare-type IV Burst Event from Proxima Centauri and Implications for Space Weather

Abstract Studies of solar radio bursts play an important role in understanding the dynamics and acceleration processes behind solar space weather events, and the influence of solar magnetic activity on solar system planets. Similar low-frequency bursts detected from active M-dwarfs are expected to probe their space weather environments and therefore the habitability of their planetary companions. Active M-dwarfs produce frequent, powerful flares which, along with radio emission, reveal conditions within their atmospheres. However, to date, only one candidate solar-like coherent radio burst has been identified from these stars, preventing robust observational constraints on their space weather environment. During simultaneous optical and radio monitoring of the nearby dM5.5e star Proxima Centauri, we detected a bright, long-duration optical flare, accompanied by a series of intense, coherent radio bursts. These detections include the first example of an interferometrically detected coherent stellar radio burst temporally coincident with a flare, strongly indicating a causal relationship between these transient events. The polarization and temporal structure of the trailing long-duration burst enable us to identify it as a type IV burst. This represents the most compelling detection of a solar-like radio burst from another star to date. Solar type IV bursts are strongly associated with space weather events such as coronal mass ejections and solar energetic particle events, suggesting that stellar type IV bursts may be used as a tracer of stellar coronal mass ejections. We discuss the implications of this event for the occurrence of coronal mass ejections from Proxima Cen and other active M-dwarfs.

Solar Activity and Lunar Precessions Influence Extreme Sea‐Level Variability in the U.S. Atlantic and Gulf of Mexico Coasts

AbstractAlong the Atlantic coast of the United States, interannual sea‐level variations of up to 20 mm are superimposed regionally upon the global average sea‐level rise (~3 mm/year) from human‐caused global warming. These variations affect the degree of coastal flooding and related damage during the highest annual tides. Interannual sea‐level variations have been attributed to several atmospheric and oceanographic processes. In the present analysis, detrended tide gauge data isolate >5‐year interannual variations. These variations can be reliably reconstructed (>77% of the variance explained) with Fourier coefficients that have frequencies related to lunar orbit (nodal and apsidal precessions) combined with solar activity. Although a causal relationship between astronomical forcing and extreme sea levels remains elusive, the reconstructions may provide an effective method for projections of extreme sea levels. Two reconstructions project that anomalously high sea levels may occur in the late 2020s, mid‐2050s, early 2060s, early 2070s, and late 2090s.

To the question on influence of solar activity on discovery of comets

To the question on influence of solar activity on discovery of comets

Evolution of the Geomagnetic Daily Variation at Tatuoca, Brazil, From 1957 to 2019: A Transition From Sq to EEJ

AbstractThe magnetic equator in the Brazilian region has moved over 1,100 km northward since 1957, passing the geomagnetic observatory Tatuoca (TTB), in northern Brazil, around 2013. We recovered and processed TTB hourly mean values of the geomagnetic field horizontal (H) component from 1957 until 2019, allowing the investigation of long‐term changes in the daily variation due to the influence of secular variation, solar activity, season, and lunar phase. The H day‐to‐day variability and the occurrence of the counter electrojet at TTB were also investigated. Until the 1990s, ionospheric solar quiet currents dominated the quiet‐time daily variation at TTB. After 2000, the magnitude of the daily variation became appreciably greater due to the equatorial electrojet (EEJ) contribution. The H seasonal and day‐to‐day variability increased as the magnetic equator approached, but their amplitudes normalized to the average daily variation remained at similar levels. Meanwhile, the amplitude of the lunar variation, normalized in the same way, increased from 5% to 12%. Within the EEJ region, the occurrence rate of the morning counter electrojet (MCEJ) increased with proximity to the magnetic equator, while the afternoon counter electrojet (ACEJ) did not. EEJ currents derived from CHAMP and Swarm satellite data revealed that the MCEJ rate varies with magnetic latitude within the EEJ region while the ACEJ rate is largely constant. Simulations with the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model based on different geomagnetic main field configurations suggest that long‐term changes in the geomagnetic daily variation at TTB can be attributed to the main field secular variation.

Breaks in Linear Trends or Parts of Cycles?

Understanding the trends and periodicities in geophysical processes is imperative for assessing and forecasting their future change. However, it is possible to mistreat parts of cycles as linear trends with sudden breaks when analysing short-term data. We demonstrate this through the analysis of solar irradiance data as well as Northern Hemisphere (NH) and Southern Hemisphere (SH) sea surface temperature (SST) data sets, with emphasis on the (a) analyses of trends in total solar irradiance (TSI) and (b) association of trends in SST with solar activity during the period from 1900 to 2017. The trends estimated using singular spectrum analysis together with linear regression revealed statistically significant long periodic non-linear trends in both TSI and SST data. Our results suggest that the appraisal of linear trends to identify their breaks/sudden changes is a biased approach when analysing data sets of shorter periods, when the data are governed by long periodic dynamical processes. The non-linear trends identified in SST data may be physically associated with the TSI trend change and anthropogenic CO2. A plausible physical mechanism is also discussed with respect to the influence of solar activity on the trend in atmospheric CO2. Finally, our study concludes that (1) breaks in linear trends are pseudo-attribution of parts of cycles, and (2) the statistically significant trends in NH and SH SST are mainly associated with loadings from trend changes in solar irradiance.

Ionospheric disturbances detected during a typhoon based on GNSS phase observations: A case study for typhoon Mangkhut over Hong Kong

Southern China is the region often affected by typhoons which have serious impacts on human beings. In this study, ionospheric disturbances possibly excited by typhoon Mangkhut in September 2018 have been investigated for the first time, by applying the Slant Total Electron Content (STEC) sequences derived from phase observations collected from Continuously Operating Reference GPS Receiver Stations located in Hong Kong (HK-CORS). Savitzky-Golay smoothing filter is employed to de-trend STEC observations, and the S transform is used to convert time domain to frequency domain for ionospheric disturbances detection. Since most significant ionospheric disturbances occurred at day time in autumn/winter and at nighttime in spring/summer, we selected nighttime GPS observations to demonstrate that the ionospheric disturbances might occur during the period of typhoon Mangkhut. On the other hand, some IGS stations far away from the typhoon were selected to verify whether the ionospheric disturbances were induced by typhoon Mangkhut. The results show that there are obvious ionospheric disturbances with a distance of about 1050 and 230 km away from the typhoon eye before and after typhoon landfall, which is related to the power of the typhoon. Meanwhile, the disturbances detected from the de-trended STEC (dSTEC) sequences for the same satellites’ observations collected from other stations located in Hong Kong occurred nearly simultaneously. The disturbance achieved its maximum with a distance about 1000 km away from the typhoon eye and then decreased. It disappeared with the distance about 2000 km away from the typhoon eye. This indicates that the typhoon can induce ionospheric disturbances after considering the influence of geomagnetic and solar activities.

Empirical orthogonal function analysis and modeling of global ionospheric spherical harmonic coefficients

We developed a global empirical model for computing spherical harmonic (SH) coefficients based on the empirical orthogonal function (EOF) method and periodic functions by utilizing global ionospheric SH coefficients data provided by Center for Orbit Determination in Europe (CODE) during the years 2005–2016. Results show that the first four-order base functions and corresponding associated coefficients can represent 97.15% of the basic characteristics of the original data. The first four-order associated coefficients have noticeable periodic variations, and the correlation between these coefficients and the solar activity intensity is high. By fitting the associated coefficients with the periodic function that takes into account the influence of solar activity, it is possible to establish an EOF model to characterize the variations of the ionospheric SH coefficients with few model parameters and further calculate the global vertical total electron content (VTEC). Relative to the existing global VTEC EOF models, this EOF method can achieve high-accuracy modeling of global VTEC with a smaller number of model coefficients. By comparing the SH coefficients and the global VTEC between the EOF model and CODE, results demonstrate that the EOF model can achieve high accuracy and reliability under different solar activities. The difference between the EOF model and CODE is basically at the same level as that between the individual ionospheric analysis centers and CODE. In the extreme event of magnetic storms, the EOF model can also present higher accuracy than the international reference ionosphere (IRI) model.

Tree-ring width based streamflow reconstruction for the Kaidu River originating from the central Tianshan Mountains since A.D. 1700

In this study, a 310-year pSeptember–August record of streamflow (where p denotes a month from the previous year) for the Kaidu River was reconstructed based on tree-ring-width from 137 Schrenk spruces (Picea schrenkiana). Spatial correlation showed that this streamflow reconstruction contains local hydroclimatic signals that approximately overlap the Kaidu River watershed. A comparison between the streamflow reconstruction for the Kaidu River and five tree-ring-based hydrological reconstructions for the surrounding areas revealed similar variations in the low-frequency domain. The results of comparison analyses between this reconstruction and other hydrological reconstructions indicated that the hydrological characteristics of the Kaidu River in the 1910s (the driest decade for the Kaidu River in the last 310 years), and the increasing trend of streamflow that began in the 1980s, might have occurred in other areas of the Tianshan Mountains and covered an even larger area. Furthermore, the highest and lowest values of this reconstructed streamflow series capture five flood or snowfall events (1803, 1804, 1836, 1923, and 1959) and six drought events (1894, 1916, 1917, 1918, 1931, and 1944) that were noted in historical documents. The 10.8- and 3.5–5.4-year cycles of this reconstruction coincided with the observed data and other tree-ring based hydrometeorological reconstructions, and revealed the possible influences of solar activity and the atmosphere–ocean system.

INFLUENCE OF SOLAR ACTIVITIES ON CLIMATE CHANGE

The solar energy received by the atmosphere of the Earth is universally distributed, which constitutes the atmospheric dynamics. The changes observed in the climate of the Earth are due to solar output variations. Some detailed reviews have accounted for the influence of solar activities on the climate using sunspot number derived from peak Sun hours, but has gaps in analyzing critical statistical background information, seasonal, latitudinal and solar activity year validation. A number of statistical concepts are explained in order to enhance our scientific knowledge of climate response to solar activity variation. The influence of geomagnetism to climate response is also examined. This review will serve as analysis and research methodology discourse which could be an application of scientific method. Additionally, this review discusses the influence of the solar activity on climate change based on the existing literature, by focusing on solar activities other than sunspot number alone. Here, we also validate methods using forward and inverse modeling, mean percentage difference, and relative variability. Results indicated that the total solar irradiance (TSI) has remained the main focus of Sun-climate interaction with somewhat negligent on energetic particle precipitation resulting from geomagnetic disturbance reaching the atmosphere. However, statistical concept remains asset to investigate the solar activity influence on climate in both local and global latitudes. We therefore recommend provision of solar quantities data to researchers for further study.

The influence of solar activity on the discovery of comets of various classes

The influence of solar activity on the discovery of comets of various classes

On the Radiative Relaxation Time for the Hydrogen–Helium Atmosphere Estimated from Changes in the Activity Factor of Jupiter’s Hemispheres

The subsolar point on Jupiter’s magnetosphere changes its position by an angle of approximately 26° over the orbital period of Jupiter, which induces seasonal variations in physical and optical characteristics of the planetary atmosphere. At the time close to the summer solstice for the northern hemisphere, Jupiter is in perihelion. Consequently, due to the significant orbital eccentricity, the energy influx into the atmosphere in the northern hemisphere is 21% larger than that in the southern one. This leads to the asymmetry in the meridional distribution of the reflectance of visible clouds. Analysis of the results of photometric observations of Jupiter for 1960–2019 showed that the ratio AJ = BN/BS adequately describes the activity of atmospheric processes on Jupiter, which shows periodic increases in brightness at tropical and temperate latitudes in the southern and northern regions by turn during one orbital period of Jupiter. The response of the atmosphere to changes in the irradiation by the Sun does not occur instantaneously but with some delay. The results of observations of Jupiter in the visible range in 1960–1995 and 2012–2019 show a synchronous delay of 3.4 year (τR ≈ 1.07 × 108 s) in response to the 21% change in the irradiation of different hemispheres when the planet is orbiting the Sun. In 1995–2012, the discrepancy caused by the orbital motion of the planet was observed between the behavior of AJ, the solar activity index Sn, and Jupiter’s regime of exposure to the Sun. Variations associated with the influence of solar activity are mainly induced by significant changes in the ultraviolet radiation of the Sun. These changes first affect the energetics of the upper atmosphere of Jupiter, after which they are indirectly transmitted into the troposphere, sometimes reducing the value of the relaxation constant τR to ~2.5 years. Since 2012, the behavior of the time dependence of AJ, the index of solar activity, and the irradiation regime of Jupiter due to its orbital motion have become consistent again. The periodicity in changes of the photometric characteristics of the northern and southern hemispheres of Jupiter were also restored.

The Influence of Solar Activity on Discoveries of Comets from Different Classes

Abstract—The paper deals with the distribution of discovery dates of comets through phases of the 11‑year cycle of solar activity (SA). Four groups of comets are considered: long-period comets (LPCs) with an orbital period exceeding 200 yr, periodic comets (PCs) of Jupiter’s family, LPCs with a weak absolute brightness, and a group of LPC with perihelia near the plane perpendicular to the ecliptic. The analysis covers the comets found before the beginning of cycle 24. The earlier conclusion on the difference between PCs and LPCs has been confirmed. It has been determined that a single maximum in the PCs distribution corresponds to the postmaximum epoch of SA. In the weak LPCs, this maximum is absent. The distribution of the isolated group of LPCs with respect to SA is also different. In all of the cases, the decay period of cycles dominates the discoveries of comets.

Rhythms of Banded Glacial Clays of the Paleoproterozoic (~2 Ga Ago) and Modern Cycles of Solar Activity

Paleoclimatic data from a sequence of argillite deposits of the Gowganda Formation located in the Mississagi River Valley (southern Ontario Province, Canada) covering a time interval of 256 years with a time resolution of one year are studied to research possible variations of the Earth’s climate in the Paleoproterozoic (~2 Ga ago). The following quasi-periodic variations have been found via the construction of a combined spectral periodogram: 3, 5, 11, 14, 29, and 75 years (at significance levels of the respective estimated values of magnitudes ranging from 2σ to 4σ). This may indicate the possible influence of solar activity on climate changes in the geological past.

Electric field measurements at mountain stations in Baksan gorge and on Cheget Peak (Elbrus region)

The results of long-term studies of the electric field in the atmospheric surface layer on the basis of data of continuous measurements carried out at the mountain stations located one - at the beginning of the Baksan gorge, the second – on the slope of Cheget mountain in the Elbrus region are presented. The influence of solar activity on the behavior of the electric field near the earth's surface is studied.