Frequency scaling of attenuation above 10 GHz

Slant path attenuation above 10 GHz has been measured radiometrically and by direct signal only at a few selected frequencies. To provide data at other frequencies, known results must be scaled down to the desired frequency. The present paper deals with multiple frequency measurements made at 19.04 and 28.56 GHz on board the D1 and D2 Comstar satellites and with sky temperature measurements made along the same paths at 11.7 GHz. Attenuation at 29 GHz is plotted against attenuation for the same percent time exceeded at 19 GHz, and the ratios of these results are compared with estimates derived from models. The ratio is almost constant at higher attenuation, but increases at lower attenuation. Attenuation at 29 and 19 GHz is plotted for the same percent time exceeded at 11.7 GHz.