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Comparison of atmospheric profiles between microwave radiometer retrievals and radiosonde soundings
Author(s) -
Xu Guirong,
Xi Baike,
Zhang Wengang,
Cui Chunguang,
Dong Xiquan,
Liu Yuanyuan,
Yan Guopao
Publication year - 2015
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd023438
Subject(s) - radiosonde , microwave radiometer , depth sounding , environmental science , meteorology , radiometer , cloud base , relative humidity , atmospheric sciences , wind speed , overcast , correlation coefficient , remote sensing , sky , physics , geography , cloud computing , mathematics , statistics , cartography , computer science , operating system
Atmospheric profiles of temperature ( T ), vapor density ( ρ v ), and relative humidity (RH) retrieved from ground‐based microwave radiometer (MWR) measurements are compared with radiosonde soundings at Wuhan, China. The MWR retrievals were averaged in the ±30 min period centered at sounding times of 00 and 12 UTC. A total of 403 and 760 profiles under clear and cloudy skies were selected. Based on the comparisons, temperature profiles have better consistency than the ρ v and RH profiles, lower levels are better than upper levels, and the cloudy are better than the clear‐sky profiles. Three cloud types (low, middle, and high) were identified by matching the infrared radiation thermometer‐detected cloud base temperature to the MWR‐retrieved temperature‐height profiles. Temperature profile under high cloud has the highest correlation coefficient ( R ) and the lowest bias and RMS, but under low cloud is in the opposite direction. The ρ v profile under middle cloud has the highest R and the lowest bias but under high cloud has the lowest R , the largest bias, and RMS. Based on the radiosonde soundings, both clear and cloudy wind speeds and drifting distances increase with height but increase much faster under clear than cloudy above 4 km. The increased wind speeds and drifting distances with height have resulted in decreased correlation coefficient and increased temperature biases and RMSs with height for both clear and cloudy skies. The differences in R , bias, and RMS between clear and cloudy skies are primarily resulted from their wind speeds and drifting distances.