共查询到20条相似文献，搜索用时 564 毫秒
1.
I. Charvátová 《Annales Geophysicae》2000,18(4):399-405
A solar activity cycle of about 2400 years has until now been of uncertain origin. Recent results indicate it is caused by solar inertial motion. First we describe the 178.7-year basic cycle of solar motion. The longer cycle, over an 8000 year interval, is found to average 2402.2 years. This corresponds to the Jupiter/Heliocentre/Barycentre alignments (9.8855 × 243). Within each cycle an exceptional segment of 370 years has been found characterized by a looping pattern by a trefoil or quasitrefoil geometry. Solar activity, evidenced by 14C tree-ring proxies, shows the same pattern. Solar motion is computable in advance, so this provides a basis for future predictive assessments. The next 370-year segment will occur between AD 2240 and 2610. 相似文献
2.
A.T. Toms H. Lühr M. Rother C. Manoj N. Olsen S. Watari 《Journal of Atmospheric and Solar》2008,70(11-12):1497-1511
The response of the equatorial electrojet (EEJ) to solar eclipses is studied in this work. We analyzed the magnetic field measurements obtained by three satellites, CHAMP, SAC-C and Ørsted and correlated them with ground-based observations during the eclipses. The observations show a local weakening of the EEJ after the shadow passed the dip equator. The size of the effect is, however, comparable with the day-to-day variability. In four out of five events we found the formation of a counter electrojet in the wake of the eclipse. We propose that the depression of the EEJ during an eclipse favors the formation of a counter electrojet. 相似文献
3.
The work describes the results of calculations obtained with the Atmospheric Research Model (ARM) general circulation model. The temperature response of the troposphere and middle atmosphere to variations in UV solar radiation were found to have a large-scale wave structure when planetary waves at the lower model boundary were taken into account. In the present paper, the results from the processing of global temperature fields with three databases (ERA-20C, NOAA-CIRES 20th Century Reanalysis, v2, and NCEP/NCAR Reanalysis I) are provided. Analysis of the differences of the mean monthly temperature global fields (January and July) between the maxima and minima of three solar activity cycles (21, 22, and 23 cycles) also demonstrated their nonzonal structure. It was shown that the amplitude of this difference in January in the stratosphere (10 hPa) can be 7–29 K in the Northern Hemisphere. In July, this effect is prominent in Southern Hemisphere. In the troposphere (500 hPa), a nonzonal temperature effect is present in both the Northern and Southern Hemispheres; the amplitude of the effects amounts to approximately 5–12 K. In conclusion, we discuss that the mechanism of solar energy impact on atmospheric temperature discovered by numerical modeling is supported after reanalysis data processing. 相似文献
4.
The relationships between different manifestations of solar and geomagnetic activity and the structural peculiarities of the dynamics of the pole wobble and irregularities in the Earth??s rotation are studied using singular spectrum analysis. There are two close major peaks and several lower ones in the same frequency range (1.1?C1.3 years) in the Chandler wobble (CW) spectrum. Components in the geomagnetic activity were distinguished in the same frequency band (by the Dst and Ap indices). Six- to seven-year oscillations in the Earth??s rotation rate with a complex dynamics of amplitude variations are shown in variations in geomagnetic activity. It is revealed that secular (decade) variations in the Earth??s rotation rate on average repeat global variations in the secular trend of the Earth??s geomagnetic field with a delay of eight years during the whole observation period. 相似文献
5.
The results of an investigation of some factors affecting the construction of the light curves for solar flares in the Hα line are presented. It is determined that the type of the light curve depends on the method of measuring the intensity, the size of the measurement window, and the brightness fluctuations of the quiet chromosphere areas (the reference areas). The light curves constructed on the basis of the flare’s peak intensity show a real picture of the flare development process. A method for the selection of the “reference areas” is suggested. 相似文献
6.
S. I. Boldyrev G. S. Ivanov-Kholodny O. P. Kolomiitsev A. I. Osin 《Geomagnetism and Aeronomy》2011,51(4):546-549
This article studies long-period variations in the Earth’s upper atmosphere density over several solar activity cycles, using
long-term data on the evolution of motion of three artificial satellites (Intercosmos-19, Meteor-1-2, and Cosmos-1154) in
orbits at heights of 400–1000 km. The time interval when the satellites were in the orbits covered three solar activity cycles
(partly the 21st, completely the 22nd, and partly the 23rd). It is found that the variations in the average density of the
upper atmosphere at heights of 400–600 km in the 1980–2000 period were governed by the changes in the solar activity level. 相似文献
7.
N. A. Barkhatov L. I. Gromova A. E. Levitin S. E. Revunov 《Geomagnetism and Aeronomy》2008,48(6):713-718
The relation of the Kp index of geomagnetic activity to the solar wind electric field (E SW) and the projection of this field onto the geomagnetic dipole has been estimated. An analysis indicated that the southward component of the IMF vector (B z < 0) is the main geoeffective parameter, as was repeatedly indicated by many researchers. The presence of this component in any combinations of the interplanetary medium parameters is responsible for a high correlation between such combinations and geomagnetic activity referred to by the authors of different studies. Precisely this field component also plays the main role in the relation between the Kp index and the relative orientation of E SW and the Earth’ magnetic moment. 相似文献
8.
The origination of various plasma inhomogeneities in the magnetosheath in front of the Earth’s magnetosphere is analyzed within classical magnetohydrodynamics. The effect of directional discontinuities or tangential and rotational discontinuities of the solar wind on plasma is studied. The origination of inhomogeneities of the type of secondary MHD waves in the magnetosheath is shown; the former equalize plasma parameters when restoring the stationary state. The effect of a rotational discontinuity on the bow shock–Earth’s magnetosphere system is of special interest, with distinguishing of plasma inhomogeneities of the plateau type observed in the near-Earth space. 相似文献
9.
10.
Monthly indices of Southern Atmospheric Oscillation (SOI) and corresponding Wolf numbers, geoeffective solar flares, magnetic AE indices as well as daily average values of the southward component of the interplanetary magnetic field (IMF B z) and data on the wind characteristics at Antarctic stations Vostok, Leningradskaya, and Russkaya are analyzed. It is shown that a sharp decrease in the SOI indices, which corresponds to the beginning of El Nin’o (ENSO), is preceded one or two months before by a 20% increase in the monthly average Wolf numbers. In warm years of Southern Atmospheric Oscillation a linear relationship is observed between the SOI indices and the number of geoeffective solar flares with correlation coefficients p < ?0.5. It is shown that in warm years a change in the general direction of the surface wind to anomalous at the above stations is preceded one or two days before by an increase in the daily average values of IMF B z. An increase in the SOI indices is preceded one or two months before by a considerable increase in the monthly average values of the magnetic AE indices. 相似文献
11.
S. A. Grib 《Geomagnetism and Aeronomy》2012,52(8):1113-1116
The collision of a solar wind tangential discontinuity with the bow shock and magnetopause is considered in the scope of an MHD approximation. Using MHD methods of trial calculations and generalized shock polars, it has been indicated that a fast shock refracted into the magnetosheath originates when density increases across a tangential discontinuity and a fast rarefaction wave is generated when density decreases at this discontinuity. It has been indicated that a shock front shift under the action of collisions with a tangential discontinuity is experimentally observed and a fast bow shock can be transformed into a slow shock. Using a specific event as an example, it has been demonstrated that solar wind tangential discontinuity affects the geomagnetic field behavior. 相似文献
12.
The spectra of radio atmospheric signals (spherics) recorded simultaneously at two observatories of the Polar Geophysical Institute, Lovozero (67.97° N, 35.08° E) and Barentsburg (78.08° N, 14.22° E), during the solar eclipse on March 20, 2015 are presented. The peculiarities of the behavior of the first critical frequency of the Earth-ionosphere waveguide during the eclipse are described. The effective altitude of the reflective layer of ionosphere is assessed. 相似文献
13.
M. A. Poluarshinov 《Geomagnetism and Aeronomy》2014,54(6):849-857
A method of recording internal gravitational waves (IGWs) from spacecraft by observing disturbances in the atmospheric emission layer, formed in the vicinity of the solar terminator and emitted in the atmospheric molecular oxygen system (762 ± 5 nm), is considered. The possibility of such observations and the efficiency of recording various characteristics of IGWs passing through the observed emission layer are estimated. 相似文献
14.
We study temporal changes of the rigidity (R) spectrum of the harmonics of the 27-day variation of the galactic cosmic ray (GCR) intensity using neutron monitors (NM) data for the period 1965–2002. We show that the rigidity spectrum of the third harmonic (9 days) of the 27-day variation of the GCR intensity changes in a similar way as the spectra of the first and second harmonics, being hard in the maximum epochs and soft in the minimum epochs of solar activity. We ascribe this finding to the alternation of the sizes of the modulation regions of the 27-day variation of the GCR intensity in different epochs of solar activity. The average size of the vicinity of the corotating interaction regions, causing the 27-day variation of the GCR intensity, is less in the minimum epochs than in the maximum epochs of solar activity. A vicinity of the corotating interaction regions of larger size involves in modulation higher rigidity particles of GCR than the vicinity of smaller size; thus, this statement can be considered as one of the reasons leading to the hardening of the rigidity spectrum of the harmonics of the 27-day variation of the GCR intensity in maximum epochs compared with minimum epochs of solar activity.We also show that the temporal changes of the power rigidity spectrum of the third harmonic of the 27-day variation of the GCR intensity are negatively correlated with the rigidity spectrum of the 11-year variation of the galactic cosmic ray intensity.We found a recurrence in the temporal changes of the amplitudes of the first harmonic of the 27-day variation of the GCR intensity and in some parameters of solar activity and solar wind. 相似文献
15.
V.V. Pipin 《地球物理与天体物理流体动力学》2013,107(1-2):185-206
We study the effect of turbulent drift of a large-scale magnetic field that results from the interaction of helical convective motions and differential rotation in the solar convection zone. The principal direction of the drift corresponds to the direction of the large-scale vorticity vector. Thus, the effect produces a latitudinal transport of the large-scale magnetic field in the convective zone wherever the angular velocity has a strong radial gradient. The direction of the drift depends on the sign of helicity and it is defined by the Parker–Yoshimura rule. The analytic calculations are done within the framework of mean-field magnetohydrodynamics using the minimal τ-approximation. We estimate the magnitude of the drift velocity and find that it can be a few m/s near the base of the solar convection zone. The implications of this effect for the solar dynamo are illustrated on the basis of an axisymmetric mean-field dynamo model with a subsurface shear layer. The model shows that near the bottom of the convection zone the helicity–vorticity pumping results mostly from the kinetic helicity contributions. We find that the magnetic helicity contributions to the pumping effect are dominant at the subsurface shear layer. There the magnitude of the drift velocity is found to be a few cm/s. We find that the helicity–vorticity pumping effect can have an influence on the features of the sunspot time–latitude diagram, producing a fast drift of the sunspot activity maximum at the rise phase of the cycle and a slow drift at the decay phase of the cycle. 相似文献
16.
Ilya G. Usoskin Laurent Desorgher Peter Velinov Marisa Storini Erwin O. Flückiger Rolf Bütikofer Gennady A. Kovaltsov 《Acta Geophysica》2009,57(1):88-101
A brief review of the research of atmospheric effects of cosmic rays is presented. Numerical models are discussed, that are
capable to compute the cosmic ray induced ionization at a given location and time. Intercomparison of the models, as well
as comparison with fragmentary direct measurements of the atmospheric ionization, validates their applicability for the entire
atmosphere and the whole range of the solar activity level variations. The effect of sporadic solar energetic particle events
is shown to be limited on the global scale, even for the most severe event, but can be very strong locally in polar regions,
affecting the physical-chemical properties of the upper atmosphere, especially at high altitudes. Thus, a new methodology
is presented to study cosmic ray induced ionization of the atmosphere in full detail using realistic numerical models calibrated
to direct observations. 相似文献
17.
A detailed representation of variations of the total solar flux I has been obtained by analyzing the regular measurements of this flux by the Nimbus-7 and other spacecrafts. In particular,
quasi-biennial variations (QBVs) of the monthly average value 〈I〉 and standard deviation sI within a month interval have been revealed. It is remarkable that the QBVs of sI almost coincide in shape with the QBVs of many solar activity and ionospheric indices, and the QBVs of 〈I〉 are almost in antiphase with the variations of sI. The manifestation of the QBVs of 〈I〉 in some processes on the Earth has been already revealed. A relation between the QBVs of 〈I〉 for solar radiation (according to the Nimbus-7 and ACRIM-2 data) and the QBVs of the zonal stratospheric wind near the equator,
as well as the QBVs of the Earth’s rotation velocity, has been found. Many of the considered QBV-processes on the Earth are
seemingly attributed to the variations of the total solar flux. 相似文献
18.
K. G. Ivanov 《Geomagnetism and Aeronomy》2010,50(3):285-297
The dynamics of the large-scale open field and solar activity at the second stage of the MHD process, including the origination
and disappearance of the four-sector structure during the decline phase of cycle 23 (the stage when the blocking field is
displaced from the main zone of active longitudes), has been considered. Extremely fast changes in the scales of one of new
sectors (from an extremely small sector (“singularity”) to a usual sector that originated after the uniform expansion (“explosion”)
of singularity with a “kick” into the zone of active longitudes, westward motion of the MHD disturbance front in the direction
of solar rotation, and formation of an active quasi-rigidly corotating sector boundary responsible for the heliospheric storm
of November 2004) have been detected in the field dynamics. It has been indicated that a very powerful group of sunspots AR
10656 (which disappeared after the explosion) with an area of up to 1540 ppmh (part per million hemisphere), a considerable
deficit of the external energy release, and zero geoeffectiveness in spite of the closeness to the Earth helioprojection existed
within singularity. It has been assumed that the energy escaped from this group with effort owing to the interaction between
coronal ejections and narrow sector walls (singularity), and a considerable part of the energy was released in the outer layers
of the convective zone, as a result of which singularity exploded and this explosion was accompanied by the above effects
in the large-scale field and solar activity. 相似文献
19.
N. D. Diamantides 《Annales Geophysicae》1998,16(5):492-509
The research task described herein aims at the structuring of an analytical tool that traces the time course of geophysical phenomena, regional or global, and compares it to the course of long-term solar conditions, long-term meaning decades or a few centuries. The model is based on the premise that since in a last analysis the preponderance of atmospheric, hydrospheric, and, possibly, some aspects of geospheric phenomena are, or have been, powered by energy issuing from the sun – either now or in the past – the long-term behavior of such phenomena is ultimately connected to long-term changes occurring in the sun itself. Accordingly, the proposed research firstly derives and models a stable surrogate pattern for the long-term solar activity, secondly introduces a transfer-function algorithm for modeling the connection between the surrogate and terrestrial phenomena viewed as partners in the connection, and thirdly probes the connection outcome for episodic or unanticipated effects that may arise due to the fact that in the present context, the connection, should it exist, is very likely nonlinear. Part I of the study presents the theory of the concept, while Part II demonstrates the concepts pertinence to a number of terrestrial phenomena. 相似文献
20.
The dynamics of the absolute global values (Φ) of the large-scale open solar magnetic field (LOSMF) fluxes at an interval of one solar rotation in 2006–2012 has been studied based on the Wilcox Solar Observatory data and using the ISOPAK original package for modeling the solar magnetic field. The reference points and the duration of the final quasi-biennial interval in cycle 23 (January 2006–May 2007; 17 months) and the phases of the cycle 24 minimum (May 2007–November 2009; 30 months), growth (November 2009–May 2012; 30 months), and the beginning of the maximum (May 2012–January 2013) have been determined. It has been indicated that the absolute values (Φ) decreased sharply at the beginning of the minimum, growth, and the maximum phases to ～(2, 1.25, 0.75) × 1022 Mx, respectively. During the entire minimum phase, LOSMF corotated super-quasi-rigidly westward in the direction of solar rotation; at the beginning of the growth phase, this field started corotating mostly eastward. The LOSMF polarity reversal in the current cycle 24 started in May–June 2012 (CR 2123–2124), when fields of southern polarity rushed from the Sun’s southern hemisphere toward the north. The statement that the solar cycle is a continuous series of quasi-biennial LOSMF intervals is confirmed. In particular, the minimum and growth phases are characterized by opposite LOSMF rotation directions, i.e., super-quasi-rigid corotation (twisting) and detwisting, with identical duration at least in cycle 24. 相似文献