Abstract:
MWP967KV ground-based microwave radiometer is an atmospheric microwave remote sensing equipment, which is jointly developed by institutes and universities in China with complete independent intellectual property rights. The microwave profiler includes 21 K-band (22-30 GHz) and 14 V-band (51-59 GHz) microwave channels. The radiometer receives radiation emitted by atmospheric oxygen, water vapor molecules and liquid water in multiple channels. The microwave, infrared and surface meteorological observations are automatically converted into continuous temperature, humidity and liquid profiles using radiative transfer equations and neural networks.In order to apply ground-based microwave radiometer MWP967KV in meteorological services, it is necessary to make comparative test analysis on its detection accuracy. The comparative test is carried out in the southern mountainous area of the Sichuan Basin from August 2015 to March 2018. The ground-based microwave radiometer MWP967KV is located at Yibin County station (28.7°N, 104.57°E) and radiosonde is located at Yibin Station (28.77°N, 104.6°E). The precision of microwave profilers and physical indexes in clear-sky, stratocumulus-sky and altocumulus-sky are analyzed and evaluated using radiosonde data as reference data and combining with ground precipitation data and cloud amount data.Results show that correlation coefficients of temperature, vapor density and relative humidity between radiometer and radiosonde in clear-sky, stratocumulus-sky and altocumulus-sky are 0.9890, 0.9665 and 0.5868, respectively, all passing 0.01 significant test. The correlation is more significant at the bottom than that in the upper air.The detection precision of temperature and relative humidity profile is obviously higher below clouds. The maximum deviation of water vapor density is on the ground and the deviation above 5 km height is close to 0.The fitted temperature profile is good, especially for high temperature. The fitted vapor density profile is also good, especially for low vapor density. However, the fitted relative humidity profile is not satisfying. For samples without temperature inversion layer, the precision of microwave profilers is higher and physical indexes are more accurate.There is no significant difference in correlation coefficient of the balloon drift distance to the deviation between radiometer and radiosonde for temperature, relative humidity and vapor density profiles under a wide range similar weather background, such as clear-sky and cloudy-sky.