我国雷暴活动对太阳耀斑响应的东西不对称性

本文研究了１９７１—１９８０年间发生在日面东部的１６４个和西部的１３２个２级以上耀斑对我国１８５个气象站上空雷暴活动的影响．结果表明，日面东部耀斑爆发后雷暴活动减弱且通过优于０．１的置信度检验测站数远多于日面西部耀斑，而日面西部耀斑爆发后雷暴活动增强，通过优于０．１的置信度检验测站数远多于日面东部耀斑．这种与地磁活动和日球扰动相似的雷暴活动对太阳耀斑响应的东西不对称性，可能借助于大气电环境并通过行星际磁场和磁层，将太阳和对流层的确耦合起来了．     

第22周上升期地磁扰动的初步分析(英文)

本文讨论第22周上升期的地磁瞬变及共转扰动。本活动周的地磁活动从1987年夏季开始上升。1988年起出现K_P≥6级扰动持续3小时以上的强主相磁爆,但多数磁爆是S(C)型延迟主相磁爆。 1988年第一、二次联测期间磁扰很弱,K_P指数基本上不超过4级。第三次联测期间发生几个中等强度的磁扰,象是冕洞引起的重现性扰动。6月28日日面S19E22发生的M6.5/2B耀斑,245MHz射电流量峰值达230,000单位,但未引起显著的地磁扰动,可能是耀斑的持续时间太短,只有13分钟。 第四次联测期间12月15日在N26E59,持续时间为128分的X1.1/1N耀斑,和12月17日在N26E37、持续184分的X4.7/1B耀斑。有两个急始型磁扰对应:12月16日的S(d)型短期弱扰动和12月17日的S(b)型强急始脉冲或小型磁暴;12月25,观测到一个典型的缓始但有明显主相的磁暴(图2)。形态相似的扰动也在4月22日(活动区在50～60°W)观测到,可能有冕洞发生在活动区所在经度附近,图1和所示的两个磁暴起源、结构都完全不同。前者对应于耀斑激波,后者对应于冕洞高速流。 图3画出1987和1988年的地磁C,指数的共转变化。从图4可以看出上述不断出现的共转扰动正是第21周似稳共转扰动的再现,预计冕洞也有相似的日面经度分布,值得注意的是1989年3月的巨大日地扰动事件恰好发生在第15卡林顿日     

太阳风暴袭击地球

10月28日太阳发生了一次强烈的耀斑爆发,耀班形成区域的面积超过地球面积的3倍,由此形成的地磁暴强度约为G-4级。与此同时,日冕物质从一个巨大的太阳黑子处抛射出来,产生的带电粒子流以大约750万千     

太阳望远镜的历史与今天（上）

2010年,太阳经历了几年活动极小年的沉寂后,日面开始逐个出现黑子。并伴随有耀斑爆发及日冕物质抛射现象,这标志着太阳进入了新的24周活动年。在未来的活动峰年里,太阳会有频繁剧烈的爆发活动吗？这些活动将对空间环境和地球造成怎样的影响呢？世界各地的科学家们正在用地面及空间太阳望远镜从不同角度、不同波段密切监视着太阳……     

地球自转变化中的太阳物理效应

对太阳活动和太阳风影响地球自转的研究现状作了评述。首先了地球自转变化的表示和测定方法，引起地球自转变化的各种扰动源以及自转长期变化中的潮汐效应和非潮汐效应。然后对地球自转变化中的太阳活动周期调制，太阳耀斑可能引起地球自转突然减速以及太阳风能否影响地球自转等问题的国内外研究现状和结果、分析作了谰论性阐述，最后作了简要总结。     

地磁脉动与太阳活动(英文)

地磁脉动作为在地面或磁层内记录到的磁流体波覆盖了很宽的频率范围(10~(-3)～10Hz),称为超低频波(ULF)。目前国际上粗略地将地磁脉动分为连续脉动(Pc)和无规脉动(Pi)两大类。Pc主要在磁平静条件下观测到的长时间连续的准正弦形的脉动。而Pi则与磁层扰动即与太阳活动有较密切的联系。 太阳耀斑效应的地磁脉动Psfe: 图1给出1988年12月16日0836UT的Psfe,由0833UT的3B级耀斑爆发引起。这类脉动过去讨论的并不多,基本特性如下: (1)只有较强的耀斑(通常二级以上)才激发这类脉动。(2) 脉动的开始通常落后于耀斑爆发时间数分钟。(3) 这类脉动必然伴随电离层D层的突然骚扰(SID)。(4)其东西分量常比南北分量强得多。(5)幅度通常较小(1nT左右)。 目前认为:Psfe脉动是耀斑引起电离层电导率局部的突然增强,因而产生电离层电流体系的扰动,它的直接激发源在电离层内,这与其它主要类型脉动源于磁层有本质不同。 与磁爆急始相关的地磁脉动Psc:图2给出1988年12月18日0225UT的伴随磁爆急始的Psc脉动。通常认为是高速太阳风对向阳面磁层的突然压缩而形成激波,这已为空间观测证实。当激波扫过地球时即观测到Psc,它是全球性的现象。Psc通常是脉冲式的,也可能含有衰减振荡。幅度很大,可达十几个nT。 Pi2脉动一磁层亚暴开始的指     

太阳活动预报与服务

我们都知道,20世纪是科学技术迅猛发展的一个世纪。特别是空间、航天技术和无线通讯技术很惹人瞩目。 随着航天技术和无线通讯技术的发展,人们意识到,空间环境状态的变化影响、制约着这些技术的实验和实施。因而,了解和认识空间环境就显得越来越重要。而空间环境扰动的驱使源是太阳。太阳的X射线爆发会引起地球电离层突然骚扰,因而影响甚至中断短波无线电通讯,而且对长波通讯也有影响;太阳大耀斑发射的强高能带电粒子流到达地球附近,会引起近地空间(卫星轨道附近)的强烈扰动,威胁人造卫星,卫星     

大太阳事件日地总体效应分析的一个例子(英文)

本文分析1986年2月4日3B/X3.0大耀斑及2月6日3B/X1.7大耀斑事件的日地总体效应。2月4日耀斑是第21周第169次X级x射线耀斑,第15个X3级耀斑,引起的质子事件是第21周第57个,>10MeV积分流量为130粒子/厘米~2.秒.球面度,粒子流产生的磁暴是19周1960年11月13日磁暴(Ap=280)以来最大的一个(Ap=202),也是1932年以来第9个大磁暴。 本文从太阳活动区演化、光学耀斑、X射线耀斑、黑子面积、X射线流量变化、太阳质子、电子、α粒子能谱、卫星高空地磁场记录、中子堆吸收、太阳风、宇宙线及地磁、电离层资料等参数,用计算机和数字化仪将这些参量画在同一时间尺度坐标上,得到太阳耀斑的光辐射和粒子辐射效应及其瞬时和滞后效应的时间序列,并作分析研究。 选择高纬南极中国长城站地磁台,低纬Honolulu台,中纬Kakioka台,北京台,Bonlder台和接近北极的Barrow台等6个地磁台磁暴急始及磁暴期间的地磁场D.H.Z.各分量形态和幅度进行分析比较。并对地磁A_p、D_(st)指数作了分析。 进一步对大事件磁暴空间环境引起的卫星异常如卫星充放电异常ESD发生在1986年2月8日、12日、以及SEU卫星异常发生在2月5日的资料作了分析。 同时,北大西洋高频无线电传播在磁暴主相后严重衰减,美国电力公司报导电压下降3％的短期效应,高频接收减低,另     

利用GPS探测电离层异常中的高斯过程处理方法

平静状态下电离层总电子含量（TEC）随时间的变化通常可以视为平稳随机过程。然而，太阳或地球的突发事件（如太阳耀斑、地磁场的扰动）会引起电离层的扰动，破坏该平稳过程，从而引起其统计参数的变化。依据平稳随机过程——高斯过程的相关性质，利用其自协方差函数和TEC时间系列，构建了独立同标准正态分布的观测样本，并利用X^2假设检验的方法来探测电离层异常现象。此外，还利用了2000年7月14日太阳耀斑期间我国国际IGS跟踪站武汉GPS跟踪站的数据，进行了实例分析。结果表明，该方法可以有效地探测电离层异常现象。     

第21周太阳耀斑活动155天左右的周期变化

近年来,许多人分别从不同波段,不同时段的观测资料,得到太阳耀斑活动存在152天—158天的周期。本文用极大熵谱估计方法逐年分析了第21太阳周(1976年—1985年)每天从全日面观测得到的1级及其以上太阳光学耀斑加权数组成的时间序列,进而得到太阳耀斑活动的155天左右的周期仅在太阳黑子活动达到极大之后三年中才比较显著的结论。这个结果对进一步了解太阳耀斑活动的规律,了解与太阳耀斑有关的日地物理量的变化,以及有效地作出太阳活动的中、长期预报都有一定价值。     

Essential features of the 11-year solar cycle

Investigation of sunspots, coronal lines intensity, flares and other solar and geophysical data have confirmed the fact that the 11-year cycle consists of two events (maxima) having different features.During the first maximum (it coincides in time with the maximum of the Wolf numbers) the solar activity increases in all heliographic latitudes but it is maximal in latitude 25° in each hemisphere. The far UV radiation and number of small spots, flares and geomagnetic disturbances with sudden commencements and without 27-day recurrences are maximum at this time.During the second maximum, which appears 2–3 years after the first one, the activity is maximal in latitudes ± 10°. At this time the biggest spots, big flares, aurora and geomagnetic disturbances with the gradual commencements and long series of 27-day recurrences appear.The variations of averaged 5303 and 6374 Å coronal line intensities may be interpreted as an increase of coronal density and temperature during the first maximum and a sharp decrease of density and temperature rise during the second one. The temperature during the second maximum is higher than that during the first one.The distribution of activity on time-latitude diagrams (so-called butterflies) is a result of superposition of two random distributions corresponding to the two maxima mentioned above.     

Analysis of the Properties of Super Solar Proton Events and Associated Phenomena

The solar flares, the speeds of shocks propagated in the solar-terrestrial space and driven by coronal mass ejections (CMEs), the heliographic longitudes and Carrington longitudes of source regions, and the geomagnetic storms, which are accompanied by the super solar proton events with a peak ?ux equal to or exceeding 10 000 pfu, have been studied by using the data of ground-based and space observations. The results show that the heliographic longitudes of source regions of super solar proton events distributed in the range from E30? to W75°. The Carrington longitudes of source regions of super solar proton events distributed in the two longitudinal belts, 130°∼220° and 260°∼320°, respectively. All super solar proton events were accompanied by major solar flares and fast CMEs. The averaged speeds of shocks propagated from the sun to the Earth were greater than 1 200 km/s. Eight super solar proton events were followed by major geomagnetic storms (Dst≤−100 nT), except that one super solar proton event was followed by a geomagnetic storm with the geomagnetic activity index Dst=−96 nT, a little smaller than that of major geomagnetic storms.     

The solar origin of geomagnetic storms

A recent study of associations between geomagnetic storms and solar phenomena has found more associations with solar flares than with coronal holes (Garcia and Dryer, 1987). This disagrees with observations of earthbound transients obtained from IPS imaging which showed that nearly all geomagnetically effective disturbances originated from coronal holes at low latitudes. The discrepancy has arisen because the former study failed to take into account the large angular extent of transient eruptions from coronal holes. It is highly probable that the intense geomagnetic storm of February 1986, discussed by Garcia and Dryer, was caused by a low-latitude coronal hole which was present at that time. This answers their question concerning moderately strong flares that apparently cause major storms, while much larger flares often do not; flares may sometimes be associated with eruptions from coronal holes, but only as peripheral events.     

A semiannual geomagnetic variation that is not dependent on the heliographic latitude effect

Hourly means of the geomagnetic elements recorded at Lerwick have been analysed to determine the effect of monthly sunspot number on the solar and lunar daily variations. The diurnal term of the solar variation in declination is found to have a distinct semiannual component that is independent of sunspot number. Thus this semiannual variation is not generated by the heliographic latitude or axial process proposed by Cortie (1912).     

Coronal holes,solar wind streams,and geomagnetic disturbances during 1978 and 1979

We have extended our long-term study of coronal holes, solar wind streams, and geomagnetic disturbances through the rising phase of sunspot cycle 21 into the era of sunspot maximum. During 1978 and 1979, coronal holes reflected the influence of differential rotation, and existed within a slowly-evolving large-scale pattern despite the relatively high level of sunspot activity. The long-lived 28.5-day pattern is not produced by a rigidly-rotating quasi-stationary structure on the Sun, but seems to be produced by a non-stationary migratory process associated with solar differential rotation. The association between coronal holes and solar wind speed enhancements at Earth continues to depend on the latitude of the holes (relative to the heliographic latitude of Earth), but even the best associations since 1976 have speeds of only 500–600 km s^-1 rather than the values of 600–700 km s^-1 that usually occurred during the declining phase of sunspot cycle 20.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.     

Some features of the solar microwave emission and their connection with geomagnetic activity

The distinction between faint and bright sources of the slowly varying component of the solar microwave emission (Paper II) is applied to statistics of the geomagnetic activity. Superposed epoch diagrams (recurrent disturbances excluded) show that the increased number of disturbed days after the CMP of sunspot groups can almost exclusively be ascribed to the spot groups associated with faint sources. The variation of the disturbance amplitude with the heliographic latitude of the spot groups is discussed. A tentative model for the solar-wind enhancement associated with a faint source is presented.For Paper I see Solar Phys. 7, 448; for Paper II see Solar Phys. 8, 204.     

Delay times between geoeffective solar disturbances and geomagnetic indices

We have examined delay times between solar disturbances (X-ray flares and DSFs) and storm sudden commencements(SSC) as well as between SSC and major geomagnetic storms. To carry out cross-correlation analysis of these point series data, we have introduced a new correlation measure which is defined by the ratio of the median value of the absolute residual differences between two sets of time series data to the one determined from hypothetical target series. We have confirmed from the correlation analyses that (1) the most probable traveling time of a solar disturbance from the Sun to the Earth is estimated to be about 2 days for a disturbance associated with major (X and M class) solar flares, and about 3 days for a disturbance associated with DSFs, (2) long-duration flares are better correlated with SSCs than short-duration flares, (3) travelling times of solar disturbances strongly depend on the heliolongitude where they originate, and (4) solar disturbances associated with flares and DSFs at the western limb can hardly reach the Earth. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cosmic-ray variations related to solar,geomagnetic and interplanetary disturbances (23 March–7 April, 1976)

During the second interval of the Study of Travelling Interplanetary Phenomena (STIP, 20 March–5 May, 1976) a series of solar, interplanetary, geomagnetic and cosmic-ray events have occurred. These are surprising events, since this period falls into the minimum of the solar activity of the past solar cycle. The present analysis is concentrated on Forbush decreases, cosmic-ray increases, geomagnetic variations and the related solar wind disturbances recorded by the heliocentric satellites Helios-1, 2 and the geocentric IMP-8, in the period 23 March–7 April, 1976. The cosmic-ray enhancements on 26 March and 1 April were of geomagnetic origin and particularly expressed in middle latitude stations during the largeDst magnetic field depressions. The detected multiple Forbush decreases are related with the type IV solar flares, all produced by the same active region (McMath Plage 14143). The relative positions among the satellites Helios-1, 2, the Sun, and the Earth were very favorable in this period for studying these events, since Helios-1 approached the Sun to its perihelion and Helios-2 was lined-up with the Earth. Helios-2 detected two shock fronts on 30 March and 1 April, respectively, and Helios-1 detected a tangential discontinuity on 26 March. An attempt is made to relate these shock fronts with the erupted solar flares and Storm Sudden Commencements (SSC) recorded on the Earth and to estimate a lower limit of the deceleration distance of the involved shock waves.     

Solar cycle variation in energetic particle emissivity of the sun

Long-term variation in energetic particle emissivity of the sun was examined by the use of PCA, solar proton flux, and geomagnetic data from 1941 to 1973. A solar cycle may be divided into three periods in terms of the Sun's particle emissivity. The first period with a peak of emissivity coinciding with the maximum of Zurich sunspot numbers is characterized by the random occurrence of proton flares along the heliographic longitude. On the other hand, active centers were restricted in certain longitude regions and had a tendency to produce a series of major flares in a week or two during the second period. The peak of particle emissivity in this period occurred a few years after the first. Relativistic proton events were observed during both the periods of enhanced particle emissivity. In the third period near the end of the solar cycle, MeV proton events of 27-days recurrency became predominating, though particle emissivity of the Sun itself was relatively low.     

Disturbances in the solar wind from IPS measurements in August 1972

From IPS and spacecraft measurements of the solar wind combined with geomagnetic observations, we identify the passage of three main disturbances through the solar wind from solar flares on August 2, 4 and 7. From a detailed study of the IPS data covering the third event, we conclude that the extent of the disturbance front at 1 AU covered about ±60° in longitude and more than 30° in latitude from the flare normal. If interpreted as a blast wave according to the model of De Young and Hundhausen (1971), the disturbance was ejected from the Sun into a cone of half-angle 45°±15°.