Improved algorithms for the determination of specific attenuation at sea level by dry air and water vapor, in the frequency range 1-350 GHz

This paper presents new algorithms for the determination of specific attenuation by dry air and water vapor, at sea level, in the frequency range from 1 to 350 GHz. The algorithms are shown to be an improvement on those recommended by the International Radio Consultative Committee (CCIR), by including the effects of high-frequency rotational transitions in oxygen, pressure-induced nitrogen absorption (important for ƒ > 150 GHz) and a quadratic dependence of attenuation on water-vapor density. Simple scaling factors are given to include the effects of temperature dependence of attenuation, over the range -20°C to 40°C.