共查询到20条相似文献，搜索用时 171 毫秒
1.
周树荣 《紫金山天文台台刊》1998,17(4):1-7
本文介绍了日食射电观测及其资料预处理的基本方法。其中包括日食观测点的选址、观测前的准备、日食观测和食后资料的预处理等。通过资料预处理 ,可得到归一化天线温度和斜率食变曲线 ,为研究日面亮度温度分布和射电源参数等基本物理量提供基本数据和资料 相似文献
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1987年9月23日日环食时,中国科学院数理化学局组织了一次多波段的射电联合观测,取得了丰富的观测资料。观测之后,又对观测资料进行了联合的分析研究,取得了很有意义的结果。本文介绍对射电日食观测资料进行分析、归算和研究的方法要点。 相似文献
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GPS卫星的激光测距和应用研究 总被引：2，自引：0，他引：2
简述了SLR和GPS跟踪技术的发展概况。详细介绍了近几年来对GPS－35、36卫星的激光测距进展和应用研究的情况。给出了残差分析的初步结果,并指出了目前GPS卫星的稀少的激光测距资料对卫星精密定轨和站坐标的解算是有价值的。同时,也简单地评述了GPS卫星的微波和激光跟踪技术各自的优势和弱点．建议联合利用GPS-35、36卫星的SLR和GPS观测资料来开展有关的应用研究。最后,对今后的应用研究工作提出了建议． 相似文献
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双星轨道拟合研究的主要目标是给出双星系统完整的运动学参数,包括质心运动学参数、二体轨道参数、恒星质量参数等.这些参数不仅是高精度、高密度星表参考架的必要组成部分,而且为恒星物理、星团和星系天文学等领域的研究提供了重要帮助.近年来,随着各种观测技术的发展和应用,特别是空间天体测量、光干涉观测和高分辨分光观测的开展,各种高精度的观测资料越来越多,双星轨道拟合也成为当前天文学研究的重要研究课题.针对联合多种观测资料的双星轨道拟合研究,本论文开展了如下几方面工作: 相似文献
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《天文研究与技术》2021,(4)
利用历史学者统计得到的春秋战国时期战争行军距离的资料,国内东周时期的石笋、树木年轮、湖泊沉积等地质气候资料以及太阳活动资料,讨论了中国古代气候变化与春秋战国时期战争的可能联系。结果表明,在几十至百年尺度上,太阳活动以及降水、气温等自然环境的变化可能间接影响了东周战争至秦统一中国的历史过程,是史学研究中值得关注的因素。与近两千年的帝制统治时期总体的气候干冷导致饥荒而引发战争的研究推断相异,本文研究发现,春秋战国时期,战争的强度大多与温度和降水正相关。古代中国以农业为本,对气候敏感的农业决定了诸侯国的经济基础,直接影响其国力,甚至可能影响了政治体制的演进和变革。 相似文献
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本文对太阳射电精细结构这一领域进行了较为详尽深入的调研 ,发现由于观测仪器技术指标 (时间、频率、频率覆盖、偏振、灵敏度等 )相对不高 ,有很多的精细结构 ,在时间上、在频率上并没有被完全分解开来 ,或是没有被检测到。对FFS的研究 ,还处于发现 -认识 -逐步深化的阶段。观测资料还很单薄。在微波高端 (厘米波段 ) ,精细结构的观测资料更是很少。另外 ,对FFS也只是有一个侧重频谱形态的分类。本文利用我国的“太阳射电宽带快速频谱仪”的观测资料 ,几年来 ,对微波频段的射电快速精细结构进行了较为深入的研究。主要研究结果有 :发现了弱偏振微波尖峰辐射中两个偏振分量之间的时间延迟和偏振反转现象 ;首次发现了微波 (短分米波段 )高偏振U型爆发并给出解释 ;首次发现了厘米波N型和M型爆发并给出解释 ;首次发现了高偏振微波斑点并给出解释 ;首次利用甚高频率分辨率频谱仪 ,通过对大样本的分米波尖峰辐射的统计 ,给出了更为可靠的、更小的相对带宽的下限 ;结合高空间分辨率的观测资料 ,对运动Ⅳ型爆发及其伴生的精细结构作了探讨 ;对双向电子束的起源及其加速位置进行了研究 相似文献
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太阳米波射电爆发是活动区上空日冕中的现象,与太阳耀斑有密切关系。近些年来,高空间分辨率的动态频谱仪获得了大量观测资料。在资料分析、理论模型和综合评述等备方面发表了许多文章。在日冕质量抛射和太阳周围磁场相互关系的研究中也取得了很大进展。 相似文献
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Summary Accurate measurements of observed frequencies of solar oscillations are providing a wealth of data on the properties of the solar interior. The frequencies depend on solar structure, and on the properties of the plasma in the Sun. Here we consider in particular the dependence on the thermodynamic state. From an analysis of the equations of stellar structure, and the relevant aspects of the properties of the oscillations, we argue that in the convection zone one can isolate information about the equation of state which is relatively unaffected by other uncertainties in the physics of the solar interior. We review the different treatments that have been used to describe the thermodynamics of stellar plasmas. Through application of several of these to the computation of models of the solar envelope we demonstrate that the sensitivity of the observed frequencies is in fact sufficient to distinguish even quite subtle features of the physics of solar matter. This opens up the possibility of using the Sun as a laboratory for statistical mechanics, under conditions that are out of reach in a terrestrial laboratory. 相似文献
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H. Q. Zhang 《Astrophysics and Space Science》2006,305(3):211-224
We discuss the study of solar magnetic fields based on the photospheric vector magnetograms of solar active regions which were obtained at Huairou Solar Observing Station near Beijing in the period of 22nd and 23th solar cycles. The measurements of the chromospheric magnetic field and the spatial configuration of the field at the lower solar atmosphere inferred by the distribution of the solar photospheric and chromospheric magnetic field. After the analysis on the formation process of delta configuration in some super active regions based on the photospheric vector magnetogram observations, some results are obtained: (1) The analysis of magnetic writhe of whole active regions cannot be limited in the strong field of sunspots, because the contribution of the fraction of decayed magnetic field is non-negligible. (2) The magnetic model of kink magnetic ropes, proposed to be generated in the subatmosphere, is not consistent with the evolution of large-scale twisted photospheric transverse magnetic field and the relationship with magnetic shear in some delta active regions completely. (3) The proposition is that the large-scale delta active regions are formed from contribution by highly sheared non-potential magnetic flux bundles generated in the subatmosphere. We present some results of a study of the magnetic helicity. We also compare these results with other data sets obtained by magnetographs (or Stokes polarimeters) at different observatories, and analyze the basic chirality of the magnetic field in the solar atmosphere. 相似文献
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I. S. Veselovsky A. V. Dmitriev A. V. Suvorova M. V. Tarsina 《Journal of Astrophysics and Astronomy》2000,21(3-4):423-429
The cyclic evolution of the heliospheric plasma parameters is related to the time-dependent boundary conditions in the solar
corona. “Minimal” coronal configurations correspond to the regular appearance of the tenuous, but hot
and fast plasma streams from the large polar coronal holes. The denser, but cooler and slower solar wind is adjacent to coronal
streamers. Irregular dynamic manifestations are present in the corona and the solar wind everywhere and always. They follow
the solar activity cycle rather well. Because of this, the direct and indirect solar wind measurements demonstrate clear variations
in space and time according to the minimal, intermediate and maximal conditions of the cycles. The average solar wind density,
velocity and temperature measured at the Earth’s orbit show specific decadal variations and trends, which are of
the order of the first tens per cent during the last three solar cycles. Statistical, spectral and correlation characteristics
of the solar wind are reviewed with the emphasis on the cycles. 相似文献
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L. H. Ma 《Solar physics》2007,245(2):411-414
Long-term variations of solar activity closely relate to terrestrial phenomena. More and more people attach importance to
studies of long-term fluctuations of solar variation. However, because direct observations of solar activity are available
only for the past four centuries, such studies are few. In this work, using the wavelet technique, the author investigates
long-term fluctuations of reconstructed sunspot number series covering the past 11 400 years, with emphasis on the thousand-year
cycle signals of solar variation. The results show a thousand-year cycle in solar activity. 相似文献
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We analyze the Wolf number daily series WN (1849 to present) as well as two other related series characterizing solar activity. Our analysis consists in computing the
amplitude of a given Fourier component in a sliding time window and examining its long-term evolution. We start with the well-known
27.03- and 27.6-day periods and observe strong decadal variations of this amplitude as well as a sharp increase of the average
value starting around 1905. We then consider a packet of 31 lines with periods from 25.743 to 28.453 days, which is shown
to be a better representation of the synodic solar rotation. We first examine the temporal evolution of individual lines,
then the energy of the packet. The energy of the packet increases sharply at the beginning of the 20th century, leading by
more than two decades the well-known increase of the Wolf number. The nonaxisymmetry of sunspots increases before the total
increase of activity and may be considered as a precursor. We discuss briefly and tentatively this observation in terms of
solar dynamo theory. 相似文献
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在研究暗条、耀斑等日面活动体的光谱时，观测谱线上都叠加上一定强度的背景光影响。如何消去这种影响对分析结果影响较大。目前，经典的方法有两大类：第一类是减法消去法，这种方法广泛为国内学者采用；第二类方法是除法消去法，即国外学者提出的（微）方模型方法。本文通过误差传递方法，比较了上述二大类方法，结果发现，所有方法的误差传递形式都是一样的，但（微）方模型的背景光误差可能要小些，至少从理论上讲要处理得合理些，因此（微）方模型要优越些。然而，从根本上讲，可以说，到目前为止，太阳圆面背景光处理问题还没有彻底解决。这方面的工作有待进一步探索。 相似文献
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本文对非线性科学的两个重要分支－分形和混沌－在太阳物理学中的应用情况作了综述，主要内容包括：太阳活动混沌性的揭示；对太阳活动混沌性的可能解释－太阳非线性发电机理论；一些太阳现象的分形描述；耀斑的自组织临界行为研究。最后给出了作者对这一领域工作前景的展望。 相似文献
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Initial studies of the Sun's corona using a solar radar were done in the 1960s and provided measurements of the Sun's radar cross-section at about 38 MHz. These initial measurements were done at a time when the large-scale phenomenon known as a coronal mass ejection was unknown; however, these data suggest that coronal mass ejections (CMEs) may have been detected but were unrecognized. That solar radar facility, which was located at El Campo, TX, no longer exists. New solar radar investigations are motivated by our modern understanding of CMEs and their effects on the Earth. A radar echo from an Earthward-directed coronal mass ejection may be expected to have a frequency shift proportional to velocity; thus providing a good estimate of arrival time at Earth and the possible occurrence of geomagnetic storms. Solar radar measurements may also provide new information on electron densities in the corona. The frequencies of interest for solar radars fall in the range of about 10–100 MHz, corresponding to the lower range planned for the low-frequency array. In combination with existing or new high-power transmitters, it is possible to use the low-frequency array to re-initiate radar studies of the Sun's corona. In this report, we review the basic requirements of solar radars, as developed in past studies and as proposed for future investigations. 相似文献
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Kenneth H. Schatten 《Solar physics》2009,255(1):3-38
Photospheric ephemeral regions (EPRs) cover the Sun like a magnetic carpet. From this, we update the Babcock – Leighton solar
dynamo. Rather than sunspot fields appearing in the photosphere de novo from eruptions originating in the deep interior, we consider that sunspots form directly in the photosphere by a rapid accumulation
of like-sign field from EPRs. This would only occur during special circumstances: locations and times when the temperature
structure is highly superadiabatic and contains a large subsurface horizontal magnetic field (only present in the Sun’s lower
latitudes). When these conditions are met, superadiabatic percolation occurs, wherein an inflow and downflow of gas scours
the surface of EPRs to form active regions. When these conditions are not met, magnetic elements undergo normal percolation,
wherein magnetic elements move about the photosphere in Brownian-type motions. Cellular automata (CA) models are developed
that allow these processes to be calculated and thereby both small-scale and large-scale models of magnetic motions can be
obtained. The small-scale model is compared with active region development and Hinode observations. The large-scale CA model offers a solar dynamo, which suggests that fields from decaying bipolar magnetic regions
(BMRs) drift on the photosphere driven by subsurface magnetic forces. These models are related to observations and are shown
to support Waldmeier’s findings of an inverse relationship between solar cycle length and cycle size. Evidence for significant
amounts of deep magnetic activity could disprove the model presented here, but recent helioseismic observations of “butterfly
patterns” at depth are likely just a reflection of surface activity. Their existence seems to support the contention made
here that the field and flow separate, allowing cool, relatively field-free downdrafts to descend with little field into the
nether worlds of the solar interior. There they heat by compression to form a hot solar-type Santa Ana wind deep below active
regions. 相似文献