中国地壳运动观测网络GPS观测方案优化研究

中国地壳运动观测网络GPS区域站采用了严格同步环、连续4天、高站点重复率的观测方案，为了优化观测方案，以青藏块体东北缘GPS区域网1999年和2001年观测资料为例，对区域GPS观测方案进行了对比试验和分析。结果表明：①同步环连续3天和连续4天观测的基线重复率和站点速度结果基本一致，可以采用站点连续3天观测的方案；②异步环有站点重复观测与无站点重复观测对比，站点速度差别很小（亚毫米级），优化观测时可以大大降低或取消异步环站点重复率；③同步环整体解算（带IGS站）与环内站点单独触算（带IGS站），其站点速率差异可达1mm以上，因此优化观测时还应尽量采用同步环观测方案。     

中国古代太阳中天观测及二至点测算精度

研究了元代《授时历议))所保存的天象观测和推步资料，得出：(1)在AD1277—1280年问所作的98次太阳中天观测的时刻及地平高度的绝对值平均误差分别为2．64min和6．78′．(2)6部古历——《大衍历》、《宣明历》、《纪元历》、《统天历》、《重修大明历》和《授时历》推步BC522年前的3个冬至时刻的误差范围为0．97—3．51d；而AD435—1280年间的45个冬至时刻的绝对值平均误差则分别为9．35、10．42、5．54、2．97、5．68、3．36h．(3)古代确定的AD442—1280年间的16个二至时刻的绝对值平均误差为199．59min，其中元代的误差为27．89min．     

丽江高美古的二期选址—筛选点的筛选

介绍了丽江高美古二期选址的筛选工作，经过踏勘确定高美古周围山头的10个点为筛选点，采用小型轻便望远镜于1998年10月16至1999年1月27日进行目视衍射环观测，并对取得的资料作了处理、分析和初步探讨。观测发现各点的视宁度没有明显差别，6     

流动重力布局评价及其观测技术

本文从流动重力测量的布局、复测周期以及观测技术等方面介绍了地震系统重力测量的现状，提出了优化现行布局、调整复测周期、提高观测技术以及改善观测条件的具体意见。指出：为了获得与地震有关的重力变化信息，当前的重点应放在布局的优化和复测周期的调整上。     

2000年度上海天文台卫星激光测距观测报告

介绍了 2 0 0 0年度上海天文台卫星激光测距观测和系统的改进情况     

福建省地壳形变观测网络建设

介绍了福建省地壳形变观测网络的建设。福建省地壳形变观测网络，以GPS观测技术为主，结合精密水准、精密重力和流动地磁测量，将3者重合到GPS观测基准站上获取观测信息，初步构成一个时空相结合，点线面与长中短兼顾的高精度、高时空分辨率的地壳形变观测网络。该网络可动态监测福建省东南沿海地区地壳运动变化，为地震预测预报提供背景信息，将取得显著的社会效益和经济效益。     

秦皇岛市区断裂活动性的SEM研究

近年来,应用断层泥扫描电子显微(SEM)构造来研究断裂的活动性,已引起了国内、外地震地质和工程地质的重视。本文通过对秦皇岛市区几条断裂带断层泥和断层泥中石英颗粒表面SEM构造特征的研究,对断裂带的相对活动时限及活动特征进行了探讨。研究成果与野外宏观调查、现场仪器测试、遥感101系统图象处理结果基本吻合,在微观领域为市区断裂活动性研究提供了依据。这说明该方法在工程地质领域具有重要的实际应用价值。     

用CCD照相多幅叠加处理检测弱星的试验

本文利用CCD动态范围大且便于数值处理的优点,观测月晕中(强背景上)的弱源。在背景尚未使CCD片子饱和时,即停止露光,存入计算机,多次露光,然后在计算机内多幅叠加,减去背景,显出弱源。通过观测试验和定量估算,结果表明,曝光重叠法,用10幅图叠加时能提高信噪比2.65倍。实测与理想情况符合较好。     

一颗与众不同的脉冲星Geminga

最近，一个困扰人们达十几年之久的γ射线源Ｇｅｍｉｎｇａ被证认为Ｘ、γ射线脉冲星，其光学对应体也被确定为一颗光谱偏蓝的２５等星。对Ｇｅｍｉｎｇａ脉冲星的确证说明存在着一类没有射电辐射的脉冲单星。     

Atmospheric densities derived from CHAMP/STAR accelerometer observations

The satellite CHAMP carries the accelerometer STAR in its payload and thanks to the GPS and SLR tracking systems accurate orbit positions can be computed. Total atmospheric density values can be retrieved from the STAR measurements, with an absolute uncertainty of 10-15%, under the condition that an accurate radiative force model, satellite macro-model, and STAR instrumental calibration parameters are applied, and that the upper-atmosphere winds are less than . The STAR calibration parameters (i.e. a bias and a scale factor) of the tangential acceleration were accurately determined using an iterative method, which required the estimation of the gravity field coefficients in several iterations, the first result of which was the EIGEN-1S (Geophys. Res. Lett. 29 (14) (2002) 10.1029) gravity field solution. The procedure to derive atmospheric density values is as follows: (1) a reduced-dynamic CHAMP orbit is computed, the positions of which are used as pseudo-observations, for reference purposes; (2) a dynamic CHAMP orbit is fitted to the pseudo-observations using calibrated STAR measurements, which are saved in a data file containing all necessary information to derive density values; (3) the data file is used to compute density values at each orbit integration step, for which accurate terrestrial coordinates are available. This procedure was applied to 415 days of data over a total period of 21 months, yielding 1.2 million useful observations. The model predictions of DTM-2000 (EGS XXV General Assembly, Nice, France), DTM-94 (J. Geod. 72 (1998) 161) and MSIS-86 (J. Geophys. Res. 92 (1987) 4649) were evaluated by analysing the density ratios (i.e. “observed” to “computed” ratio) globally, and as functions of solar activity, geographical position and season. The global mean of the density ratios showed that the models underestimate density by 10-20%, with an rms of 16-20%. The binning as a function of local time revealed that the diurnal and semi-diurnal components are too strong in the DTM models, while all three models model the latitudinal gradient inaccurately. Using DTM-2000 as a priori, certain model coefficients were re-estimated using the STAR-derived densities, yielding the DTM-STAR test model. The mean and rms of the global density ratios of this preliminary model are 1.00 and 15%, respectively, while the tidal and latitudinal modelling errors become small. This test model is only representative of high solar activity conditions, while the seasonal effect is probably not estimated accurately due to correlation with the solar activity effect. At least one more year of data is required to separate the seasonal effect from the solar activity effect, and data taken under low solar activity conditions must also be assimilated to construct a model representative under all circumstances.