(5.4) Where frequency (GHz) f = represents total air pressure rp ptot/1013, ptot 288/(273 rt t) pressure (hPa) p t temperature (C) The specific attenuation due to water vapor is calculated using the following equations: w (5.5) (5.6) (5.7) (5.8) where is the water-vapor density (g/m3). Exemplary result for the specific attenuation from 1 to 350 GHz at sea-level for dry air (p=1013 hPa, t=15°C) and water vapor with a density of =7.5 g/m3 (from [5.2]) is shown in Figure 5.1. Figure 5.1: Exemplary results for specific attenuation due to dry air and vapour Calculation of the Specific Attenuation due to Rain according to ITU-R P. 838-3 R The specific rain attenuation is calculated according to according to ITU-R P. 838-3 [5.3]: R
(5.4) Where f frequency (GHz) rp = ptot/1013, ptot represents total air pressure rt 288/(273 t) p pressure (hPa) t temperature (C) The specific attenuation w due to water vapor is calculated using the following equations: (5.5) (5.6) (5.7) (5.8) where is the water-vapor density (g/m3). Exemplary result for the specific attenuation from 1 to 350 GHz at sea-level for dry air (p=1013 hPa, t=15°C) and water vapor with a density of =7.5 g/m3 (from [5.2]) is shown in Figure 5.1. Figure 5.1: Exemplary results for specific attenuation due to dry air and vapour Calculation of the Specific Attenuation R due to Rain according to ITU-R P. 838-3 The specific rain attenuation R is calculated according to according to ITU-R P. 838-3 [5.3]: