Long-term ground-based microwave radiometric measurements of atmospheric brightness temperature in SKYNET Hefei (31.90N, 117.17E) site

- Long-term observations of atmospheric brightness temperature are studied in SKYNET Hefei using the radiometer (model WVR-1100).
- Results of cumulative distributions of zenith TB from Hefei site are different from other regions with seasonal variations.
- Long-term observations of TB are useful for investigating water vapor and cloud of regional climate.

A dual-frequency, ground-based microwave radiometer (WVR-1100) is used to investigate the behavior of the atmosphere in terms of zenith brightness temperature (TB) at 23.8 and 31.4 GHz respectively. Some experimental findings in SKYNET Hefei site from September 2002 to August 2012 are presented. The cumulative distributions of TB at both frequencies for all sky conditions show four different regions, while only two regions can be identified for clear, lightly cloudy and cloudy condition. Annual cycle of TB at 23.8 GHz is apparently remarkable, indicating the large annual cycle of atmospheric water vapor. Regular seasonal variations of TB are observed with the strongest value in summer and the weakest in winter.