我国20个地区大气折射指数垂直分布的三种统计模式

THREE STATISTICAL MODELS FOR VERTICAL DISTRIBUTION OF ATMOSPHERIC REFRACTIVE INDEX IN 20 REGIONS OF CHINA

利用我国２０个测站常规探空资料，运用大气折射理论和统计学方法建立了大气折射垂直分布的三种统计模式。分析结果表明：目前使用的４／３地球半径模式精度较差，只有在离地面１ｋｍ高度以下使用，才能保证精度；改进的等效地球半径模式精度最高；指数模式在离地面３ｋｍ高度以下使用。

An attempt is made to establish three statistical models for vertical distribution of atmospheric refractive index based on the theory and approach with the aid of conventional radiosonde record from the selected 20 stations in China. Results show that Ⅰ) the 4/3 equvalent earth′s radius model yields minimum accuracy and is applicable to within 1 km of the surface; Ⅱ) the modified version gives maximum accuracy; Ⅲ) the exponential model is effective in the lowest 3 km.