A statistical survey of atmospheric index-of-refraction variation

Abstract

This paper presents a statistical survey of index-of-refraction variations as recorded by an airborne microwave refractometer. Scales and intensities of the index variations are given, as well as the parameter\overline{\DeltaN^{2}}/l, for data taken over southwest Ohio during summer months and over the Pacific Ocean off the west coast of Washington in August and of California in October. Heights from 2,000 to 25,000 feet, msl, were considered with most of the data taken between 2,000 and 12,000 feet. Approximately 1,200 samples taken on 34 flights were analysed. The composite of the data gave the following median values: Index Scale = 130 feet Index Intensity =0.3 N\frac{\overline{\DeltaN^{2}}}{l} = 7 \times 10^{-4}N^{2}/ft