共查询到20条相似文献，搜索用时 93 毫秒
1.
地球自转变化与中国大陆地震活动关系的初步分析 总被引：10，自引：0，他引：10
本文利用天文观测的日长变化时间序列和我国地震资料，统计分析了地球自转十年尺度变化、年限变化和季节性变化与中国大陆地震活动间的相关性。结果表明，中国大陆地震活动与地球自转变化在时间尺度上存在着一定的全局性联系，地球自转变化引起的附加应力可能对中国大陆地震活动起一定的触发作用，中国大陆地震活动与地球自转变化在空间尺度上存在着一定的地区性联系，以东西向的天山地震带与日长变化的相关性最为显著，南北向的中轴地震带和东西向的燕山地震带次之，而北北东向的山西地震带跟日长变化则没有确定的对应关系。分析结果表明，天文观测的地球自转资料可以为我国大陆地震预测提供一种参考依据。 相似文献
2.
日长年际变化,ElNino／南方涛动和大气准两年振荡的小波分析 总被引：4，自引：0，他引：4
本文采用1964-1993年期间日长变化序列、海平面气压和纬向风速资料，通过小波变换等技术研究分析日长年际变化与ElNino／南方涛动、大气准两年振荡之间的关系．结果表明，日长年际变化与ElNino／南方涛动存在着相似的谱结构，而且ElNino／南方涛动叠加上大气准两年振荡后，与日长变化序列的小波变换时频谱更趋于一致．本文研究结果证实，ElNino／南方涛动和大气准两年振荡的贡献基本能够解释地球自转的年际变化． 相似文献
3.
大气对地球自转季节性变化的贡献 总被引：2，自引：0，他引：2
采用１９７９－１９９５年期间新的大气角动量资料,研究了大气在季节性时间尺度上对日长变化和极移的贡献。结果表明,考虑了风和大气压的贡献后,大气在周年和半年时间尺度上对日长变化的贡献分别可达９５％和８８％。同时还给出了大气对极移激发的定量结果,其中,大气的周年尺度上对极移Ｘ分同的贡献为１６％,对Ｙ分量的贡献为４３％;在半年尺度上海洋的贡献,才能进上步解决地球自转激发的问题。 相似文献
4.
全球陆地水储量对地球自转变化的激发作用 总被引：5，自引：2，他引：3
用美国环境预测中心和美国大气研究中心(NCEP/NCAR)40年重新分析计划气候数据同化系统(CDAS)所得到的全球陆地水储量(土壤湿度和积雪水当量)数据,对地球自转变化(极移和日长)的激发作用作了分析．结果表明,陆地水储量对周年地极移动正频分量的激发为17．8mas,与大气激发相当,相位滞后约48°．其中,积雪水当量的激发结果与用人卫遥感技术所得到的积雪水当量激发的正、负频率分量的振幅和相位都符合得很好．
用陆地水储量数据得到对日长变化周年分量的激发作用约49μs,约占观测激发的15％,相位滞后约23°;对日长变化半年分量的激发作用约9μs,约占观测激发的3％,相位滞后约122°． 相似文献
5.
本通过分析1996.0至1990.0年期间分布于太平洋海域的88个验潮站所观测到的海平面变化（SLC）资料序列，以及国际地球自转服务的日长变化（△LOD）资料序列，初步研究了海平面变化与地球自转的关系。实测资料的分析结果表明，在年限时间尺度上，日长变化与东太平洋赤道带区域的海平面变化成正相关，而与西太平洋区域的海平面变化成负相关。根据海平面变化具有位相超前的现象，证实海平面的变化可能对地球自转速率产生激发贡献。近30年的资料分析表明，太平洋的平均海平面正以每年1.8毫米的速率上升。通过本研究工作使我们认识到海平面变化的观测数据是深入革球自转研究的一种重要资料源。 相似文献
6.
大气对地球自转参数（ERP）的高频激发 总被引：4，自引：0，他引：4
本文采用１９８３—１９９２年期间由空间大地测量技术观测和归算的地球自转参数（ＥＲＰ）序列，以及由全球气象资料归算的大气角动量（ＡＡＭ）序列，分析和研究了大气对地球自转参数的日长变化（ＬＯＤ）和极移（ｘ和ｙ）在一个月时间尺度以内的高频激发作用，得到的主要结果如下：１大气对ＬＯＤ分量高频潮汐的估计值存在着影响，但是，潮汐形变参数ｋ／ｃ随时间和频率的变化却是受非大气因素的扰动引起的．２．大气可以解释３０天以下ＬＯＤ非潮汐的大部分变化．３．极移分量３０天以内的高频变化也主要由大气激发．ｘ分量与大气的相关性要强于ｙ分量，而且更为稳定，主要表现为平均时间尺度约为２７天的波动，大气对这个波动的贡献可达７０％． 相似文献
7.
用带通滤波方法从日长变化(LOD)、南方涛动指数(SOI)和Nino各海区海面温度异常变化(SSTA)等资料中提取年际和年代际变化分量,研究了Nino3．4海区SSTA的年代际分量对ENSO事件的调制作用．研究发现,除了年际分量之外, SSTA的年代际分量对ENSO事件的表征和监测有重要影响．当ENSO事件比较强时,SSTA年代际变化分量的作用倾向于使ENSO事件的时间延长,并使事件的极端温度增大;当ENSO事件比较弱时,在SSTA年际变化中没有检测到的事件,可借助于年代际变化分量的调制作用得到检测．还研究了SSTA年际和年代际变化与SOI、热带太平洋海平面气压异常(SLPA)和信风异常(TWA),以及大气角动量(AAM)和海洋角动量(OAM)轴向分量(χ3)的相应变化之间的频谱相干性．结果表明在年际尺度上,SSTA与LOD、SOI、SLPA、TWA、大气角动量的轴向分量(χω3,χpib3和χωpib3)和海洋角动量的轴向分量(χv3和χv bp3)等都有密切关系,其中以SOI、SLPA、TWA和χω3与SSTA的关系更加显著;在年代际时间尺度上,SSTA与SOI、SLPA、TWA、χω3以及χω v3的关系更为密切,与LOD、大气压(χpib3)和洋底压强(χbp3)的关系较弱． 相似文献
8.
地震引起地球自转速率变化的分析 总被引：2，自引：0，他引：2
由地震引起地球内部质量重新分布将影响地球惯量量矩的变化，从而引起地球自转速率的变化，即日长的变化。一般说，大地震产生大的附加位移违抗和。它对地球自转特性有影响。本文采用Ｈａｒｖａｒｄ目录中１９７７－１９９４年产的地震有关参数，和根据地震激发地球自转的变化理论及Ｄａｈｌｅｒ和Ｌａｍｂｅｃｋ有关公式计算了地震引起地球辆向惯量矩的变化。结果表明：由单个地震引起的日长变化要比观测值小几个量级，它的累积效应 相似文献
9.
γ Cas是一颗Be/x-ray双星.紫台于1986年冬用新安装在60cm反光镜上的Marly-Nanjing非球面光(?)摄谱仪对其作了光谱观测.本文简要介绍了观测期间Ha、HeIλ5875与HeIλ6678发射线轮廓的特征及其待值宽度在天与天之间,数小时之间变化. 相似文献
10.
引力常数变化对地球自转长期变化的影响 总被引：1，自引：0，他引：1
李林森 《中国科学院上海天文台年刊》2002,(1)
探讨和估计了各种引力常数变化理论对地球角速度和日长变化的影响。各种引力常数变化理论包括了引力常数G随时间、空间以及速度变化等几个方面的影响。另外也估计了对地球自转角速度和日长变化产生的效应。其中有些研究对探讨地球自转变化也有启发意义。 相似文献
11.
The shape of the Earth and of planets depends on the exciting forces and on the rheology of the medium. From the equilibrium equation, we present the main modelisations of the viscous and inviscid fluids and we essentially describe the characteristics of linear viscoelastic deformations, for the Maxwell viscoelastic model of rheology. We use the elastic, viscoelastic and fluid Love numbers in order to investigate the associated relaxation modes. For these various kinds of rheology of the planets interior, we compute the geoid and the topography induced by an internal mass distribution. Finally, we show the importance of this viscoelastic deformation calculations in the study of the celestial body rotations. 相似文献
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13.
Jia-Qing Zheng Mauri J. Valtonen Leena Valtaoja 《Celestial Mechanics and Dynamical Astronomy》1990,49(3):265-272
It is generally assumed that the Solar System is surrounded by a swarm of comets, the so-called Oort Cloud, which contains approximately 1011 members. The observed comets belong to a small subsection of the Cloud, and they have very elongated orbits. The origin of the Cloud is presently unclear. Here we consider the possibility that the comets were born in a star cluster together with the Sun. We follow the evolution of the star cluster with its embedded swarm of comets and calculate the rate at which stars accumulate stable comet companions. We conclude that if the Oort Cloud of comets was born in this process, then the present day density of comets in interstellar space has to be high, and that comets make a significant contribution to the overall mass density of the Galaxy. 相似文献
14.
大行星轨道运动与太阳黑子数的中长周期变化 总被引：1，自引：1，他引：0
杨志根 《中国天文和天体物理学报》1988,(4)
本文对不同序列的太阳黑子数资料作了分析研究,计算得到了可能的太阳黑子活动的中长周期变化,并分别与由大行星轨道运动引起的日心轨道角动量变化的周期进行比较,发现二者具有比较一致的谱结构。基于本文的讨论和文[17]的结论,我们进一步认为大行星轨道运动是太阳黑子数周期性变化的可能的外部因素。 相似文献
15.
Irregular satellites—moons that occupy large orbits of significant eccentricity e and/or inclination I—circle each of the giant planets. The irregulars often extend close to the orbital stability limit, about 1/3-1/2 of the way to the edge of their planet's Hill sphere. The distant, elongated, and inclined orbits suggest capture, which presumably would give a random distribution of inclinations. Yet, no known irregulars have inclinations (relative to the ecliptic) between 47 and 141°.This paper shows that many high-I orbits are unstable due to secular solar perturbations. High-inclination orbits suffer appreciable periodic changes in eccentricity; large eccentricities can either drive particles with ∼70°<I<110° deep into the realm of the regular satellites (where collisions and scatterings are likely to remove them from planetocentric orbits on a timescale of 107-109 years) or expel them from the Hill sphere of the planet.By carrying out long-term (109 years) orbital integrations for a variety of hypothetical satellites, we demonstrate that solar and planetary perturbations, by causing particles to strike (or to escape) their planet, considerably broaden this zone of avoidance. It grows to at least 55°<I<130° for orbits whose pericenters freely oscillate from 0 to 360°, while particles whose pericenters are locked at ±90° (Kozai mechanism) can remain for longer times.We estimate that the stable phase space (over 10 Myr) for satellites trapped in the Kozai resonance contains ∼10% of all stable orbits, suggesting the possible existence of a family of undiscovered objects at higher inclinations than those currently known. 相似文献
16.
中国古历定朔推步综述 总被引：10，自引：0，他引：10
“朔”简言之表日月黄经相等，先民对其认识经历了一个从平朔到定朔的过程，通过研究古历，文中分析并归纳了不同时期中国古历日制度的基本元素之一－朔的两种推步方法：“积年法”和“《授时历》法”，其中包括平朔，日躔，月离，及定朔的推步方法等；得出了由各历的基本历数直接推出的中国古历定朔计算的一般公式，同时亦给出了《授时历》的推朔法和部分算例。 相似文献
17.
We present BVRI colors of 13 jovian and 8 saturnian irregular satellites obtained with the 2.56 m Nordic Optical Telescope on La Palma, the 6.5 m Magellan Baade Telescope on La Campanas, and the 6.5 m MMT on Mt. Hopkins. The observations were performed from December 2001 to March 2002. The colors of the irregular satellites vary from grey to light red. We have arbitrarily divided the known irregular satellites into two classes based on their colors. One, the grey color class, has similar colors to the C-type asteroids, and the other, the light red color class, has colors similar to P/D-type asteroids. We also find at least one object, the jovian irregular J XXIII Kalyke, that has colors similar to the red colored Centaurs/TNOs, although its classification is insecure. We find that there is a correlation between the physical properties and dynamical properties of the irregular satellites. Most of the dynamical clusters have homogeneous colors, which points to single homogeneous progenitors being cratered or fragmented as the source of each individual cluster. The heterogeneously colored clusters are most easily explained by assuming that there are several dynamical clusters in the area, rather than just one, or that the parent body was a differentiated, heterogeneous body. By analyzing simple cratering/fragmentation scenarios, we show that the heterogeneous colored S IX Phoebe cluster, is most likely two different clusters, a grey colored cluster centered on S IX Phoebe and a light red colored cluster centered on S/2000 S 1. To which of these two clusters the remaining saturnian irregulars with inclinations close to 174° belong is not clear from our analysis, but determination of their colors should help constrain this. We also show through analysis of possible fragmentation and dispersion of the six known uranian irregulars that they most likely make up two clusters, one centered on U XVI Caliban and another centered on U XVII Sycorax. We further show that, although the two objects have similar colors, a catastrophic fragmentation event creating one cluster containing both U XVI Caliban and U XVII Sycorax would have involved a progenitor with a diameter of ∼395 km. While such an event is not impossible it seems rather improbable, and we further show that such an event would leave 5-6 fragments with sizes comparable to or larger than U XVI Caliban. The stable region around Uranus has been extensively searched to limiting magnitudes far beyond that of U XVI Caliban. The fact that only U XVI Caliban, the larger U XVII Sycorax and four much smaller objects have been found leaves us with a distribution not compatible with a catastrophic event with such a large progenitor. The most likely solution is therefore two separate events creating two uranian dynamical clusters. 相似文献
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D. I. Podolsky 《Astronomy Letters》2002,28(7):434-437
The recently detected accelerated expansion of the Universe is related to the existence of a new type of matter called the Λ field or quintessence. Constraints were obtained on its equation of state from the absence of clustering of this matter on scales much smaller than the cosmological horizon. The question of how these constraints affect the possibility of fitting the accelerated expansion by such cosmological models as the Chaplygin gas model is discussed. 相似文献
20.
本文把我们在文[1]和[2]中建立的诊断方法,应用于美国高山天文台斯托克斯参量仪对1978年12月11日太阳黑子本影和半影取得的Q和U两个参数的轮廓,发现这个黑子的磁力线不呈现较强的扭绞。 相似文献