A Model of Temperature Stratification for Correction of Leveling Refraction

摘要

Refraction causes leveled height differences to be too small. It is usually considered to be the largest known systematic error in leveling measurements amounting to as much as a cm/km. In 1937, long before refraction was widely accepted as a significant error source, a correction was developed. Few countries adopted the correction, but it is now realized that the correction is necessary, especially in the middle and lower latitudes. Removing refraction bias from old leveling measurements requires a temperature stratification model. The model described is based on historical records of solar radiation, sky cover, precipitation, and ground albedo from many locations in the conterminous United States. This modeling method can be adopted by any country with records of solar radiation.