1986-1991年期间我国六架仪器的时纬观测分析

AN ANALYSIS OF OPTICAL OBSERVATIONS IN CHINA DURING 1986-1991

本工作对我国六架经典仪器1986－1991年的时纬观测进行分析，得到它们相对于国际地球自转服务系统的“O－C”序列；由“O－C”序列研究它们的周年和半年变化特点并用它们的剩余误差研究了“异常”变化与台站附近发生的地震之间的可能关系。

Till the end of 1991, there were 6 Chinese optical instruments which were doing their observations to determine UTO-UTC and local latitude. In order to show the changes of the local vertical and environment, an effort was made to analyse these observations in this paper.Fig .1 shows the phase distribution of the annual and semi-annual terms of the O-C series of the observations. It seems that all Chinese observations may be affected by some common error sources such as the regional error of steller cata-logues, the error of nutation coefficients and the local environment in China.Fig. 2 shows the residuals of the O-C series. There are some anomalous varia-tions shown in the figures by short bars in both peak and valley of the curves.Table 3 lists all anomalies of the O-C residuals and earthquakes in the area near the stations. Some anomalies appear up to 3-4 months in advance of the earthquakes. It is suggested that some of the anomalies be related to the earthquakes.