映射函数形式的天文大气折射理论公式

Astronomical refraction theoretical formula in mapping function form

重新研究了中性大气折射延迟映射函数的近似母函数.在此基础上,本文得到了一个新的天文大气折射的理论公式,即映射函数形式的表达式.数值计算表明,利用本文公式和利用普尔科沃大气折射表公式计算的蒙气差相差很小.在天顶距小于30°的情况下,二者之差小于0″.05,在天顶距小于65°的情况下,二者之差小于0″.11;在天顶距大于65°的情况下,二者之差却不增反降,直至在天顶距75°处出现负值,但也就是在天顶距75°处,二者之差的绝对值又开始增加;但总体上,在天顶距小于75°时二者之差的绝对值小于0″.11.可见,以映射函数形式的蒙气差公式取代复杂的普尔科沃大气折射表公式是可行的,也可以利用天文大气折射测定值来建立大气延迟模型.

This paper has restudied approximate generating function of neutral atmospheric refractive delay mapping function which is given by the literature. On basis of this restudy this article gets a new astronomical refraction theoretical formula, i.e. expression of mapping function form. Numerical calculation shows that the calculated astronomical difference between using this paperrs formula and using refraction tables of Pulkovo is very small. Under the condition of zenith distanced〈30°,the difference between them is less than 0.05＂, in the case of zenith distance less than 65°, the difference between them is less than 0.11＂, under the condition of zenith distance greater than 65°, the difference between them decreaces. Until negative value appears at zenith distance 75°, but at just this zenith distance, the absolute value of difference between them becomes increasing. It can be seen that in the case of zenith distance less than 75°, the absolute value of difference between them is less than 0. 11＂. It is feasible to use the mapping function form astronomical refraction formula to replace the complex Plkovo refraction table formula. It also can build the atmospheric delay model by making use of astronomical refraction measured values.