Attenuation Induced by Water Vapor Along Earth-Space Links: Selecting the Most Appropriate Prediction Method

This communication presents an improved approximate method for the estimation of water vapor attenuation along Earth-space slant paths, over the 1-350-GHz frequency range. Evaluated against a large set of radiosonde data, the proposed method provides more accurate results than those delivered by the current alternative approximation methods included in Annex 2 of recommendation ITU-R P.676-10. This result is important as it sheds light on which approximate water vapor attenuation model should be selected for predictions along Earth-space slant paths.