Ground-based W-band Cloud Measurement Radar Detection Capability Analysis And Preliminary Research On Cloud Parameter Inversion

In recent years,millimeter-wave cloud radar technology has developed rapidly in China.Millimeter-wave radar is favored by many scholars for its advantages in detecting non-precipitation clouds.At present,domestic Ka-band cloud radar technology has become mature,and is developing the W-band cloud radar technology.Compared with Ka-band cloud radar,W-band cloud radar has a shorter wavelength,back-scattering ability is stronger,so it can detect smaller particles.This paper is a research content of Atmospheric Profiling Synthetic Observation System(APSOS)supported by National Key Scientific Instrument and Equipment Development Project(leaded by Institute of Atmospheric Physics,Chinese Academy of Sciences).This paper uses the first ground-based W-band cloud radar of China developed by Anhui Sun Create Electronics Co.,Ltd.in APSOS,discussed the radar's detection capabilities,and researched the cloud parameters detected at Huainan,Anhui and Yangbajing,Tibet.The main research contents and results of this paper are as follows:(1)The radar system parameters,technical index and calibration conditions were introduced.Through the joint observation experiment of Huainan and Yangbajing,the radar has been operating in good condition.It can satisfy the continuous observation of cloud target.(2)W-band cloud radar technology has not yet matured in China.Its ability to detect clouds is worth focusing on.This paper discussed the radar's detection capabilities,including the scattering and attenuation of radar electromagnetic waves and the minimum detectable echo intensity of radar,and analyzed the echoes of two cases.The results show that for W-band radars,the scattering of Mie will result in weakening of echoes when large particles such as precipitation are encountered;The effects of W-band radar attenuation cannot be ignored.Using the bin-by-bin correction method,a preliminary study of attenuation corrections was completed.Further corrections need to consider factors such as particles phase,shape,size and echo intensity;Radar detection capability can be improved by selecting suitable signal processing methods.It is recommended to select 256 pulse accumulations in the vertical view mode.(3)Cloud radar not only provides intuitive cloud macro parameters,it also can retrieve cloud micro-physics parameters.This paper uses the threshold method to extract the macro parameters of the cloud.Using foreign single radar retrievaltechnology to retrieve micro-physics parameters.According to different cloud types,a suitable empirical formula was chosen to carry out retrieval of liquid water content,ice water content and effective particle radius.And compared with a lidar with pulse energy of 550 mJ.The results show that lidar has advantages in detecting thin clouds with its high sensitivity.When the thickness of the clouds layer exceeds 1.5km,lidar cannot penetrate the clouds.Cloud radar is superior to lidar in detecting thick clouds and multi-layer clouds.When detecting clouds above 8km,the detection capability is poor and the sensitivity needs to be improved.After many experiments found:although the two radars have differences in detection capabilities,the detected cloud area and the derived micro-physics parameters are all within the theoretical error range and have good consistency.