反常折射引起的地面天文观测残差的周年变化

THE ANNUAL VARIATION OF OPTICAL ASTRONOMICAL OBSERVATIONAL RESIDUALS CAUSED BY THE ANOMALOUS REFRACTION

我国光学天文观测有相当长历史，观测精度也较高，但是与国际系统相比，无论是测时还是测纬，所有仪器残差都有类似的周年变化．本文作者认为部分原因是由于我国季节变化引起的大气等密度层倾斜，从而产生的反常折射所引起的。文中对反常折射的规律进行了研究，导出了由于气象参数变化而引起的反常折射公式，并与测时，测纬的残差周年项进行了对比。结果表明用反常折射可以部分地解释我国天文观测残差的周年变化。

The optical astronomical observations in China have lasted for a long time and most of them have a good accuracy. But refering to the BIH system, for all the instuments, their residuals have a similar annual variations in time and latitude determinations. The author thinks that to some extent may be due to the anomalous refraction from the tilting of equi-density level of the atmosphere, which is variable with the season. In this paper, the formula of calculating the anomalous refraction from meteorologic parameters is given, and the rules of anomalous refraction are discussed. The results show that the annual variations in time and latitude determinations in China can be partially explained with the anomalous refraction.