Analysis And Research On The Microphysical Characteristics Of Cloud Precipitation Based On GPM And Ground-based Radar

Based on the success of the Tropical Rainfall Measuring Mission?TRMM?,the United States and Japan jointly developed the Global Precipitation Measurement program.GPM-CO is the main satellite of this program which was launched on February 28,2014.It has been in orbit for more than five years.It is equipped with the world's first satellite-based dual-wavelength precipitation radar?Dual-frequency Precipitation Radar,abbreviated as DPR?and multi-wavelength microwave imager?GPM Microwave Imager,abbreviated as GMI?,which has accumulated a lot of precipitation data.A large amount of data was provided for the study of the vertical structure of global precipitation.At present,there are still few applications for GPM and its products in China,and there are few comparative studies of GPM and its cloud microphysics and precipitation inversion products and ground-based dual-polarization radar inversion products.In this paper,the dual-wavelength precipitation detection radar,GPM products and precipitation inversion algorithm carried by GPM are introduced.The difference of four scanning modes of DPR in the detection ability of surface precipitation is compared.The ability of GPM_DPR to detect precipitation is compared and studied,which is based on two precipitation cases observed by ground-based X-band dual-polarization radar and two-dimensional raindrop spectrometer?2DVD?in Beijing on July 19,2016 and July 6,2017.This paper studies four detection modes of GPM,which are Ku single-frequency radar scanning?Ku_NS?,Ka radar matching scanning?Ka_MS?,Ka radar high sensitivity scanning)and dual-frequency radar joint inversion?DPR_MS?,and the following conclusions are obtained:1.Ka_HS detection can detect more precipitation information with low rainfall intensity,and it mainly identifies precipitation information with rainfall intensity less than 10 mm·h^-1.Ka_HS has strong recognition ability to detect precipitation information with rainfall intensity less than 0.4 mm·h^-1.Ka_MS has poor recognition ability for precipitation information with rainfall intensity less than 0.4 mm·h^-1,and the rainfall intensity that can be identified is mainly distributed in 0.4 to 10 mm·h^-1.The precipitation recognition effect with rainfall intensity greater than 10 mm·h^-1 is also poor.Ku_NS can detect the most precipitation information and has stronger recognition ability for weak precipitation than DPR_MS and Ka_MS.DPR_MS can get more precipitation information than Ka_HS and Ka_MS.2.Through the quantitative evaluation of two precipitation cases at 21:5 on July 6,2017 and 11:56 on July 19,2016,The ground-based X-band dual-polarization radar is more consistent with Ku_NS when the precipitation intensity is between 0.8 and 20mm·h^-1,it is concluded that the rainfall intensity obtained by ground-based X-band dual-polarization radar and Ku_NS inversion is between 0.8 mm·h^-1 and 20 mm·h^-1,and the results correspond well.Due to the limitation of accuracy,the X-band dual-polarization radar obtains more weak precipitation information than Ku_NS.In addition,the rain intensity center obtained by Ku_NS corresponds well with the rain intensity center obtained by X-band dual-polarization radar,and is stronger than the rain intensity center obtained by X-band dual-polarization radar.The rainfall intensity obtained by ground-based X-band dual-polarization radar and Ka_MS inversion is between 0.8 mm·h^-1 and 20 mm·h^-1,and the results correspond well.The rainfall intensity obtained by X-band dual-polarization radar inversion is slightly stronger than that obtained by Ka_MS inversion.To sum up,Ka_HS has the strongest ability to detect weak precipitation,and Ku_NS has the strongest ability to detect heavy precipitation.The precipitation information detected by Ka_MS is mainly distributed between 0.4 mm·h^-1 and 10mm·h^-1.DPR_MS combines the advantages of Ka_MS and Ku_NS and the detection ability is ideal.In addition,in the view of precipitation inversion,the ground-based radar estimated precipitation corresponds well to the detection data of precipitation intensity between 0.8 mm·h^-1 and 20 mm·h^-1 detected by space-borne radar.The detection data greater than 20 mm·h^-1 corresponds poorly,which is probably due to the deformation of large particles under the influence of air flow,and coupled with the different observation angles,resulting in detection errors.The results still need to be further analyzed.