共查询到20条相似文献，搜索用时 406 毫秒
1.
I. A. Bakunina A. A. Solovyev Yu. A. Nagovitsyn Yu. V. Tikhomirov V. L. Bakunin D. V. Prosovetsky S. M. Kuznetsova 《Geomagnetism and Aeronomy》2009,49(8):1087-1090
The following has been indicated for the cyclotron emission of microwave sources based on a simple modeling of a unipolar
sunspot magnetosphere by the magnetic monopole, submerged in subphotospheric layers, and a temperature, changing with altitude
as hyperbolic tangent. At insignificant changes in the sunspot magnetic field strength, originating as a result of oscillations
of a sunspot as an integrated structure, the oscillation amplitude (in percent) of brightness temperatures of the Stokes I and V parameters at a wavelength of 1.76 cm (NoRH) is an order of magnitude as large as the magnetic field strength amplitude.
This amplitude is of the same order of magnitude as the field oscillation amplitude at a wavelength of 5.2 cm (SSRT). 相似文献
2.
A. Mete Işikara 《Pure and Applied Geophysics》1973,102(1):120-123
Summary The article describes lunar daily magnetic variation inH, D andZ components of the earth's magnetic field at Istanbul. Maximum occurs at 10.03 l.hr. (lunar hour) in theH component, 3.38 l.hr. in theD and 2.15 l.hr. in theZ component, during the period 1949 to 1968. Also, the seasonal variation of the lunar magnetic variation has been determined and it is seen that the variation of the phase inD andZ are opposite from the phase of the lunar variation inH, and the amplitudes of the lunar variation inH, D andZ are greatest during the northern solstice. 相似文献
3.
A. G. Tlatov 《Geomagnetism and Aeronomy》2013,53(8):953-956
Relative variations in the number of sunspots and sunspot groups in activity cycles have been analyzed based on data from the Kislovodsk Mountain Astronomical Station and international indices. The following regularities have been established: (1) The relative fraction of small sunspots decreases linearly and that of large sunspots increase with increasing activity cycle amplitude. (2) The variation in the average number of sunspots in one group has a trend, and this number decreased from ～12 in cycle 19 to ～7.5 in cycle 24. (3) The ratio of the sunspot index (Ri) to the sunspot group number index (G gr) varies with a period of about 100 years. (4) An analysis of the sunspot group number index (G gr) from 1610 indicates that the Gnevyshev-Ohl rule reverses at the minimums of secular activity cycles. (5) Ratio of the total area to area of Ssp/Sum nuclei has long-term variation with a period approximately 8 cycles. Minimum ratio falls on 16–17 cycles of activity. (6) It has been indicated that the magnetic field intensity and sunspot area in the current cycle are related to the amplitude of the next activity cycle. 相似文献
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5.
W. P. Olson 《Pure and Applied Geophysics》1989,131(3):447-462
Since the discovery of the magnetosphere, it has been known that the currents flowing in the magnetosphere contribute toSq, the regular daily variation in the earth's surface magnetic field. The early models, however, were not very accurate in the vicinity of the earth. The magnetospheric contribution toSq has therefore been recalculated by direct integration over the three major magnetospheric current systems; magnetopause, tail and ring. The finite electrical conductivity of the earth, which increases the horizontal and decreases the vertical components of the magnetospheric field at the earth's surface, has been taken into account. The magnetospheric currents are found to contribute 12 nanotesla to the day to night difference in the mid-latitudeSq pattern for steady, quiet magnetospheric conditions. They also contribute to the annual variation in the surface field and must be considered an important source of the observed day to day variation in theSq pattern. 相似文献
6.
Summary Solar and lunar geomagnetic tides inH at Alibag have been determined by spectral analysis of discrete Fourier transforms following the method of Black and the well-known Chapman-Miller method. The seasonal variation inL
2(H) is opposite to that inL
2(D) with maximum in thed season and minimum in thej season. In bothH andD the enhancement due to sunspot activity is larger in lunar tide than in solar tide. Surprisingly, the enhancement due to magnetic activity is greater inL
2(H) than inS
1(H), while the contrary is true for declination. It is inferred that there is a local time component of the storm time variation contrary to the view expressed by Green and Malin. The enhancements in amplitudesL
2 andS
1 inH andD, due to sunspot activity and due to magnetic activity, have been separated. The results show that the amplitude at zero sunspot number increases with magnetic activity in all the four parameters, while the enhancement due to sunspot activity at different levels of magnetic activity decreases with increase ofK
p. But if bothK
p andR are increasing, whenK
p increases enhancement due toR decreases and whenR increases enhancement due toK
p decreases. 相似文献
7.
8.
Emil M. Apostolov Vojtěch Letfus Reviewer J. Pýcha 《Studia Geophysica et Geodaetica》1989,33(4):379-390
Summary The time variations of the amplitudes and phases of the semi-annual variation in geomagnetic activity, characterized by the linear planetary index aa, have been analysed for the period 1868–1985. The results provide qualitative confirmation of Murayama's conclusions [13] about the systematic f phase in dependence on the changes in the level of solar activity and give support to Russel-McPherron's mechanism [16] concerning the effect of the predominant polarity of the interplanetary magnetic field. A distinctly expressed variation of the phase differences in the course of the sunspot cycle and of the 22-year cycle, and specific variations related to the sequence of four consecutive cycles have been established, as well as a well-defined 90-year period, all of them as a reflection of analogous variations in solar activity. The variations of the phase differences observed around the equinoxes can be explained by the combined effect of the mechanisms of the axial and equinoctial hypothesis. It is assumed that a displacement of the maxima of the semi-annual variation to dates after the equinoxes will be observed in the ascending parts and a reverse displacement towards the equinoxes and earlier dates in the desccending parts of the following sunspot cycles 22 nad 23.On leave from the Geophysical Institute of the Bulgarian Academy of Sciences, Akad. G. Bonchev Str. bl. 3, Sofia 1113, Bulgaria. 相似文献
9.
本文根据苏黎世天文台太阳黑子11年周期资料和太阳黑子磁场磁性变化周期特征，构建了太阳黑子磁场磁性指数MI(Magnetic Index)时间序列.分析表明：太阳活动磁性周期平均长度为222年，但是每个周期长度是不相等的；多数情况周期短时磁性指数较大，对应太阳活动水平强；周期变长时磁性指数较小，对应太阳活动水平较弱；太阳黑子磁场磁性指数序列也具有80～90年的世纪周期. 进一步研究指出，太阳黑子磁场磁性指数曲线由极小值升至极大值时期，太阳磁场南向，行星际磁场磁力线与地磁场磁力线重联，此时磁层为开磁层，太阳风将携带大量等离子体从向阳面进入地球磁层，从而使输入的动量、能量和物质大幅度增加，与北半球对流层增温时期对应；太阳黑子磁场磁性指数曲线由极大值下降至极小值时期，太阳磁场北向，与磁层顶地磁场同向，行星际磁场不会与地磁场发生重联，此时磁层为闭磁层，这种情况下，只有少数带电粒子能够穿越磁力线进入地球磁层，与北半球对流层降温时期对应. 相似文献
10.
《Journal of Atmospheric and Solar》2002,64(15):1617-1621
Effects of the solar activity on the geomagnetic Sq field were studied by examining the correlation of the Sq amplitude in the Y-component with the sunspot number or height integrated Pedersen and Hall conductivities of the ionosphere at Kakioka, Chambon La Foret and Port Moresby for a period of 21 years. It was found that solar activity dependence of the Sq amplitude is almost explained by the effect of the local ionospheric conductivity if the month is fixed. That is, the solar activity dependence in each month is mainly caused by the local conductivity. However, the amplitude is clearly small in winter for the same conductivity value. This is probably due to the seasonal difference of the neutral winds driving ionospheric dynamo currents or to the magnetic effect of the field-aligned currents connecting both hemispheres driven by the asymmetric dynamo action in the ionosphere. 相似文献
11.
R. G. Rastogi 《Pure and Applied Geophysics》1958,40(1):145-156
Summary The mean monthly noon critical frequencies of theE andF1 layers of the ionosphere at a number of stations in different latitudes and their variation with sunspot number have been studied in this paper. It is found that while theE layer approximates to a chapman region, theF1 layer is markedly affected by other agenices, somewhat similar toF2. In high sunspot years,foF1 shows two maxima at middle latitudes with a minimum at the equator. 相似文献
12.
V. N. Pogrebnoi V. P. Golovkov T. I. Zvereva E. L. Mozoleva S. Moldobekova 《Geomagnetism and Aeronomy》2010,50(4):536-541
The results of investigations of the latitudinal distribution of annual variation of the geomagnetic field level in the seasons
of 1964 (International Quiet Sun Year) using the data from 95 world magnetic observatories located at various longitudes in
the latitude range 83° N–90° S are reported. The latitudinal features of the X, Y, and Z components of the geomagnetic field have been analyzed. It has been shown that the amplitudes (summer-winter differences)
of the annual variation are maximal in the polar regions, decrease continuously to zero towards the equator, and are identical
for both the Northern and Southern hemispheres with a half-year delay (local summer). The amplitudes of the equinox-winter
difference in the equinox periods are smaller than those in summer, but are manifested simultaneously in the Northern and
Southern hemispheres. An equivalent circumpolar current system has been constructed, which is responsible for the annual variation
of the geomagnetic field level. Its parameters have been determined. 相似文献
13.
It has been indicated that special moments (turning points), when certain characteristics of the latitudinal (equatorward) drift of the sunspot drift zone suddenly change, exist in each 11-year solar cycle. The moment when a sunspot formation low-latitude boundary minimum (T2), coordinated in time with the end of a polar magnetic field polarity reversal, exists has a special place among these points. A conclusion has been drawn that it is impossible to reconstruct polarity reversal moments in the past based on information about turning points T2. The average velocities of the latitudinal drift of the minimal, average, and maximal sunspot group latitudes have been calculated. It has been indicated that the closeness of the relationship between the first two velocities and the maximal activity amplitudes in the cycles differ substantially for the first (before point T2) and second (after point T2) cycle parts. The corresponding values of the correlation coefficients increase substantially in the second cycle (after point T2). It has been established that a relationship exists between some velocities calculated in these cycles and the activity amplitudes at maximums of the next cycles. A model for predicting future cycle maximums has been constructed based on this conclusion. The probable average annual Wolf number at a maximum of cycle 24 has been determined (W(24) = 93). 相似文献
14.
There are limited homogeneous instrumental observations of the sunspot magnetic fields, but the Earth is a sort of a probe reacting to interplanetary disturbances which are manifestation of the solar magnetic fields. We find correlations between some parameters of geomagnetic activity (the geomagnetic activity “floor”—the minimum value under which the geomagnetic activity cannot fall in a sunspot cycle, and the rate of increase of the geomagnetic activity with increasing sunspot number), and sunspot magnetic fields (the sunspot magnetic field in the cycle minimum, and the rate of increase of the sunspot magnetic field from cycle minimum to cycle maximum). Based on these correlations we are able to reconstruct the sunspot magnetic fields in sunspot minima and maxima since sunspot cycle 9 (mid 19th century). 相似文献
15.
Martin Franke 《Pure and Applied Geophysics》1949,14(1-2):120-131
Zusammenfassung Die vonJ. G. Brown vertretene Auffassung, den doppelperiodischen Tagesgang des luftelektrischen Potentialgefälles an Landstationen als Ueberlagerung eines einfach- periodischen Ganges und einer austauschbedingten Depression darzustellen, wird mit Hilfe berechneter Tagesgänge des Austauschkoeffizienten quantitativ bestätigt.
Herrn Prof. Dr.W. Peppler zum 65. Geburtstag gewidmet. 相似文献
Summary Following a suggestion ofJ. G. Brown of regarding the local variation of the earth's electric field at land-stations as mainly caused by the cycle of turbulence, convection, and subsidence the problem of the double-period of the daily variation of the earth's electric field has been numerically solved. By computed values of the daily variation of the «Austauschkoeffizient», an exact measure of atmospheric turbulence, basing on temperature observations of Leafield (England) for clear days, the daily variation of nuclei has been computed for; thus getting additionally the daily variation of ions, conductivity, and local potential-gradient. Combining this computed variation of the potential-gradient and the unitary variation of the earth's field over oceans shows a double-period (local time) of the potential-gradient of the earth's electric field at land-stations. Thus the problem of the double-period of the daily variation of the earth's electric field has been reduced to one of a single-period which cannot be explained by the «Austausch».
Herrn Prof. Dr.W. Peppler zum 65. Geburtstag gewidmet. 相似文献
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17.
对2016—2019年华北中部地区（34.7°—41.1°N,110.3°—119.7°E）流动地磁矢量观测数据进行处理,得到连续3期岩石圈磁场年变化数据,并对岩石圈磁场空间分布形态进行分析。研究发现,磁异常分布与岩石圈结构之间有一定相关性,在太行山隆起以西、临清坳陷、鲁西断隆和鲁西断隆以东等主要结构单元表现出不同程度的差异性,但在各自单元内却呈现出较好的整体性,岩石圈磁场水平矢量H和东向分量ΔY要素分区特征较明显。从H矢量空间分布形态可以看出,高能量区多分布在太行山隆起以西和鲁西断隆周边。文水—日照ΔY要素剖面幅值变化形态与结构分区间对应较好,对主要结构单元ΔX、ΔY、ΔZ要素异常幅度均值和极值进行统计,结果表明,太行山隆起以西近期岩石圈磁场变化幅度最大,异常能量最强,其次为鲁西断隆及以东地区,而临清坳陷周边磁场变化相对较平稳。 相似文献
18.
J. Bitterly J. M. Cantin R. Schlich J. Folques D. Gilbert 《Surveys in Geophysics》1984,6(3-4):233-239
A new portable magnetometer theodolite with fluxgate sensor has been developed for measuring the components of the earth's magnetic field. With this instrument, used as a null detector, it is possible to make absolute measurements of declination (D) and inclination (I). The compensation of the main magnetic field allows direct intensity measurements (H, X, Y, Z components); in this case the calibration is made by reference to a proton magnetometer.The observation procedure is particularly easy and quick. The accuracy is better than 5 sec of arc forD andI and better than 1 nT for direct intensity measurements. 相似文献
19.
The purpose of this research is to demonstrate the possibility of applying one geophysical method to studying untraditional systems as is the case with Portland-cement-based materials. The research demonstrates how conventional paleomagnetic methodology can be employed in studying the mode of magnetic recording in present-day industrial materials. Portland-cement admixtures such as fly ashes and furnace slags should be discriminated, because those particles interact in soils and sediments in nature. Moreover, a better undertanding of magnetic remanent acquisition in model materials can serve to improve the interpretation of magnetic remanent acquisition in natural rocks formed a long time ago. The magnetic constituents of Portland-cement paste and mortar acquire a magnetic remanence due to their alignment with the earth's magnetic field at the casting place. This magnetization can be measured using ordinary paleomagnetic techniques. The alignment of the individual magnetic particles accounts for the intensity of the magnetic remanence, which can be increased by adding water and by vibration before setting and hardening. Blast furnace slag admixtures also add to the enhancement of the intensity of remanence. The magnetization of Portland-cement-based materials shows a near linear relationship with the water /cement (w/c) ratios employed in the experimental work; the w/c ratios range between 0.2 – 0.6 in pastes and 0.3 – 0.6 in mortar. Stable remanent magnetization was obtained during the first seven days of setting and hardening, a period necessary for magnetic particles to become locked parallel to the earth's magnetic field. The stability of magnetic remanence predicts the usefulness of the methodology in studying the properties of Portland cement and particularly in the control of iron-bearing admixtures. 相似文献
20.
Ernesto R. Rodríguez Flores Rafael Gmez Díaz Ramn E. Rodríguez Taboada 《Journal of Atmospheric and Solar》2005,67(17-18):1728
Based on high-resolution (0.3 arcsec) observations, we studied the behavior of solar granulation in the neighborhood of a sunspot. The bright granules’ spatial distribution and the granules’ surface density as a function of distance from the center of the sunspot umbra were determined.Bright granules distribute delimiting cells of dimensions in the mesogranular scale. The mean diameter of these cells does not show significant variation with the variation of the magnetic field of the sunspot. The granules’ surface density does not show significant variation with distance to the sunspot umbra. Both results point to a very weak, if any, influence of the sunspot magnetic field at distances greater than 20 arcsec. 相似文献