Retrieval of Atmospheric Vertical Motion Velocity and Raindrop Spectrum for a Convective Cloud Precipitation
Retrieval of atmospheric vertical velocity and raindrop spectrum distribution is important in the study of cloud precipitation mechanism and cloud microphysics,which is of great significance for artificial weather prediction and weather intervention.For a convective cloud precipitation detected by a millimeter-wave radar in Anhui province on August 29,2021,this work processed its power spectrum data and retrieved atmospheric velocity and raindrop spectrum.The small particle tracer method is introduced and improved.The points which correspond to the minimum power in the effective cloud segment were selected as tracers for retrieving atmospheric vertical velocity.First,according to the small particle tracer method and the improved one,atmospheric velocity from the power spectrum data is obtained.Then,a comparative analysis is carried out against the results of the atmospheric velocity retrieved from the base data.The falling velocity of particles in still air is then obtained.According to existing empirical formula between particle falling velocity and particle diameter,particle diameters were calculated.The research is shown as follows.(1)The results of atmospheric velocity obtained by the improved small particle tracer method are more accurate than those obtained by the original method,and the error between the two methods is larger inside the cloud than outside of it.On this basis,the particle falling velocity is further obtained.Combined with the weather conditions during the detection period,the obtained particle velocity can well match with the atmospheric velocity and is consistent with the information of convective cloud weather.Particle concentration is the main parameter for retrieving the spectral distribution of raindrops.During the rapid development of the cloud,internal particles keep expanding to the outside,and particle concentration inside the cloud is small but relatively(and unexpectedly)large at the cloud boundary.
millimeter-wave radarpower spectrum datasmall particle tracer methodatmospheric vertical movement velocityraindrop distribution