Radiometer based measurements of slant-path attenuation in the V/W bands

Slant path brightness temperatures were measured at 72.5 and 82.5 GHz with a multi-channel radiometer. One year of measurements collected at 36° elevation angle in Rome, NY were examined in terms of the attenuation statistics. A model-based attenuation retrieval algorithm was developed to determine the slant path attenuation cumulative distribution function to over 20 dB of attenuation corresponding to less than 1% exceedance probability. Slant path attenuation was also measured with the radiometer using the sun as a source of radiation. Over 30 dB of attenuation dynamic range was possible with this technique. Sun-beacon measurements were used to test model predictions.