The Effect of Solar Activity on the Annual Precipitation in the Beijing Area   总被引：3，自引：0，他引：3  

Juan Zhao  Yan-Ben Han  Zhi-An LiDepartment of Astronomy  Beijing Normal University Beijing  zj@bnu.edu.cnNational Astronomical Observatories  Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2004,4(2):189-197

Using continuous wavelet transform, we examine the relationship between solar activity and the annual precipitation in the Beijing area. The results indicate that the annual precipitation is closely related to the variation of sunspot numbers, and that solar activity probably plays an important role in influencing the precipitation on land.  相似文献   

2001-2002年上海天文台卫星激光测距观测报告     

杨福民  张忠萍  陈婉珍  陈菊平 《中国科学院上海天文台年刊》2003,(1)

介绍了 2 0 0 1- 2 0 0 2年上海天文台卫星激光测距观测概况和亚厘米级精度的测距实验  相似文献   

A weak outburst of the millisecond X-ray pulsar SAX J1808.4-3658 in October 1996 as detected from RXTE slew data     

M. G. Revnivtsev 《Astronomy Letters》2003,29(6):383-386

Analysis of the RXTE slew data in October 1996 revealed a weak X-ray burst from the millisecond pulsar SAX J 1808.4-3658. The 3–20-keV energy spectrum of the source can be described by a power law with an index of 2.0 and a(3-to 20 keV) luminosity of ～1.4×10³⁵ erg s^?1 (the distance to the source was taken to be 2.5 kpc). Because of the short exposure time, we failed to detect weak pulsations at a frequency of 401 Hz in the source. The (2σ) upper limit of the pulse fraction is ～13%.  相似文献   

区域GPS网实时计算可降水量的若干问题   总被引：1，自引：0，他引：1  

SONG Shuli ZHU Wenyao 《中国科学院上海天文台年刊》2003,(1)

目前地基GPS气象学测得的可降水量 (PWV )精度好于 2mm ,但在利用区域GPS网实时计算每个测站上空的PWV时 ,要涉及到很多常规GPS资料处理时所忽略的问题 ,如需考虑数据处理软件和计算方式的选择、站坐标的确定和约束、轨道的使用方法、网外辅助站最佳数量的确定、海潮对实时计算PWV的影响以及实时应用于气象服务时的端部效应等问题。利用上海GPS综合应用网获取的 2 0 0 2年 6、7月份长江三角洲地区入梅前后的数据 ,分析了利用区域性的GPS网实时计算高精度的PWV时要解决的各种问题 ,探讨了其数据处理方案  相似文献   

Automated Separation of Stars and Normal Galaxies Based on Statistical Mixture Modeling with RBF Neural Networks     

Dong-Mei Qin  Ping Guo  Zhan-Yi Hu  Yong-Heng ZhaoNational Laboratory of Pattern Recognition Laboratory  Institute of Automation  Chinese Academy of Sciences  Beijing  dmqin@nlpr.ia.ac.cnDepartment of Computer Sciences  Beijing Normal University  Beijing National Astronomical Observatories  Chinese Academy of Sciences  Beijing 《中国天文和天体物理学报》2003,3(3)

For LAMOST, the largest sky survey program in China, the solution of the problem of automatic discrimination of stars from galaxies by spectra has shown that the results of the PSF test can be significantly refined. However, the problem is made worse when the redshifts of galaxies are not available. We present a new automatic method of star/(normal) galaxy separation, which is based on Statistical Mixture Modeling with Radial Basis Function Neural Networks (SMM-RBFNN). This work is a continuation of our previous one, where active and non-active celestial objects were successfully segregated. By combining the method in this paper and the previous one, stars can now be effectively separated from galaxies and AGNs by their spectra-a major goal of LAMOST, and an indispensable step in any automatic spectrum classification system. In our work, the training set includes standard stellar spectra from Jacoby's spectrum library and simulated galaxy spectra of EO, SO, Sa, Sb types with redshift ranging from 0 to 1  相似文献   

On the Period Variation of the W UMa-type Contact Binary V502 Ophiuchi     

Qing-Yao Liu  Yu-Lan Yang National Astronomical Observatories/Yunnan Observatory  Chinese Academy of Sciences  Kunming   《中国天文和天体物理学报》2006,6(3):331-337

The variation in the orbital period of the W UMa type contact binary V502 Oph is analyzed. The orbital period exhibits a wavelike variation with a periodicity of 23.0 years and an amplitude of △P = 1.24×10~(-6) days superimposed on secular decrease of dP/dt = 1.68×10-7 day per year. The long-term decrease may be accompanied by the contraction of the secondary at a rate of 83 m per year and a mass transfer rate from the primary to the secondary of 4.28×10~8 M per year. The short-term oscillation may be explained by the presence of a third component. Orbital elements of the third body and its possible mass are presented.  相似文献   

银河系运动学参数的确定     

俎中良  赵君亮 《中国科学院上海天文台年刊》2004,(1)

利用 2 0 2个太阳附近疏散星团的视向速度和自行观测资料 ,对太阳的运动和银河系的运动学参数进行了研究。其中 ,距离在 0 .5kpc到 2kpc之间的 12 8个疏散星团对平均太阳运动分量的解算结果是 (u0 ,v0 ,w0 ) =(- 13.8± 1.4 ,- 5 .0± 1.6 ,- 11.6± 2 .9)km/s ;Oort常数和银河系径向运动参数的解算结果分别为 (A ,B) =(16 .9± 1.1,- 11.6± 2 .6 )km·s- 1·kpc- 1及 (C ,D) =(2 .5± 1.1,- 2 .1± 0 .9)km·s- 1·kpc- 1。  相似文献   

疏散星团NGC6530天区的恒星自行和成员概率     

温文  赵君亮陈力 《中国科学院上海天文台年刊》2005,(1):79-94

利用上海天文台的照相底片资料,确定了疏散星团NGC6530天区364颗恒星的自行和成员概率,并对有关自行测定的方法、结果和精度等问题作了较为详细的介绍和讨论。使用的底片历元差为87年,全部恒星自行中误差的均方根值为1．09mas/a。  相似文献   

The equilibrium configuration of rapid rotating compact stars and some gravitational effects     

Jun Dong  Jing-li Sun  Pei-chen Zhu 《Chinese Astronomy and Astrophysics》1986,10(4):278-286

In this paper, the equilibrium configurations of rapid rotating compact stars and some gravitational effects are studied within the general relativity by use of the Harrison-Wheeler equation of state and by the self-consistent field method. Numerical calculations show that the equilibrium configuration of a rotating star is a spheroid. For large spin velocities, say, ω > 3.0 × 10² sec⁻¹ the eccentricity and mass increase very rapidly as the angular velocity increases, for the critical angular velocity of the rotating star, the eccentricity is about 0.7, the increase in mass is about 10–35%. The difference of the gravitational redshifts at the surface of the star caused by rotation, and the difference of the light bending when the beam moves in the direction of rotation or in the opposite direction are obvious.  相似文献   

Sedimentary petrology and geochemistry of siliciclastic rocks from the upper Jurassic Tordillo Formation (Neuquén Basin, western Argentina): Implications for provenance and tectonic setting     

Luis A. Spalletti  Ignasi Queralt  Sergio D. Matheos  Ferrn Colombo  Jorge Maggi 《Journal of South American Earth Sciences》2008,25(4):440-463

The Upper Jurassic Tordillo Formation is exposed along the western edge of the Neuquén Basin (west central Argentina) and consists of fluvial strata deposited under arid/semiarid conditions. The pebble composition of conglomerates, mineralogical composition of sandstones and pelitic rocks, and major- and trace-element geochemistry of sandstones, mudstones, and primary pyroclastic deposits are evaluated to determine the provenance and tectonic setting of the sedimentary basin. Conglomerates and sandstones derived almost exclusively from volcanic sources. The stratigraphic sections to the south show a clast population of conglomerates dominated by silicic volcanic fragments and a predominance of feldspathic litharenites. This framework composition records erosion of Triassic–Jurassic synrift volcaniclastic rocks and basement rocks from the Huincul arch, which was exhumed as a result of Late Jurassic inversion. In the northwestern part of the study area, conglomerates show a large proportion of mafic and acidic volcanic rock fragments, and sandstones are characterised by a high content of mafic volcanic rock fragments and plagioclase. These data suggest that the source of the sandstones and conglomerates was primarily the Andean magmatic arc, located west of the Neuquén Basin. The clay mineral assemblage is interpreted as the result of a complex set of factors, including source rock, climate, transport, and diagenesis. Postdepositional processes produced significant variations in the original compositions, especially the fine-grained deposits. The Tordillo sediments are characterised by moderate SiO₂ contents, variable abundances of K₂O and Na₂O, and a relatively high proportion of ferromagnesian elements. The degree of chemical weathering in the source area, expressed as the chemical index of alteration, is low to moderate. The major element geochemistry and Th/Sc, K/Rb, Co/Th, La/Sc, and Cr/Th values point to a significant input of detrital volcanic material of calcalkaline felsic and intermediate composition. However, major element geochemistry is not useful for interpreting the tectonic setting. Discrimination plots based on immobile trace elements, such as Ti, Zr, La, Sc, and Th, show that most data lie in the active continental margin field. Geochemical information is not sufficiently sensitive to differentiate the two different source areas recognized by petrographic and modal analyses of conglomerates and sandstones.  相似文献