Consistency Analysis And Comparison For Observations From CINRAD/SA And TRMM PR

Nowadays ground-based radars net system becomes an important means for monitoring and warning of weather systemand promotes the analysis of meso-scale weather system. In order to improve consistency of each ground-based radar from ground-based radars net system, this paper select stable Precipitation Radar (PR) onboard the Tropical Rainfall Measuring Mission (TRMM) satellite as reference to research the echo difference from single ground-based radar and TRMM PR, to analyze the stability of single ground-based radar for several years and the difference from ground-based radars. Based on the reflectivity factor difference between TRMM PR and single ground-based radar, fit single ground-based radar reflectivity so that improve the consistency between single ground-based radar and TRMM PR as well as between ground-based radars.The Geometry-matching method is applied to analyze the reflectivity of Nanjing radar and TRMM PR as well as Changzhou radar and TRMM PR.476 match-up cases and 393689 match-up points from 2003 to 2014 for Nanjing radar,266 match-up cases and 230175 match-up points from 2009 to 2014 for Changzhou radar. The results reveal that single ground-based radar is well corresponding to TRMM PR in detecting rainfall, match-up area concentrated in within-BB-height and below-BB-height area and most match-up points are weak echo. The below-BB-height data of single ground-based radar reveal that single ground-based radar has a unstable performance for several years, the echo intensity changes with time and accompanies a time segmented feature. The working period of 12 years for Nanjing radar can be divided into 5 stages and the 6 years for Changzhou radar can be divided into 4 stages. Overall reflectivity within each stage remains relatively stable, but distinct differences of overall reflectivity factor exits among the stages,the differences of overall reflectivity factor among the stages is 2-3 dB.The reflectivity factor difference between TRMM PR and ground-based radar changes with the increasing of echo intensity and shows a linear relationship. The reflectivity factor of TRMM PR surpassed ground-based radar in low intensity echo, while in high intensity echo ground-based radar surpass TRMM PR. On account of the fitting relationship between the two radar reflectivity factor. Fit the relationship of reflectivity factor between single ground-based radar and TRMM PR in each stages,the Mie scattering correction and the segmented linear correction are applied to the reflectivity of ground-based radar, which are both effective to improve the consistency of single ground-based radar. The differences of overall reflectivity among the stages is reduce to less than 0.4dB and standard deviations of reflectivity differences of all match-up cases is reduced from 2dB to 1.2dB.With 153 match-up cases when TRMM flies pass both Nanjing radar and Changzhou radar simultaneously, reflectivity factor comparison of Nanjing radar and Changzhou radar indicates that distinct difference between two ground-based radars, the variation of difference with time. The difference could reach 7dB and echo mosaics manifest discontinuity. The segmented linear correction based on TRMM PR is applied to the reflectivity of single ground-based radar in each corresponding stages. The result shows reflectivity difference of two ground-based radar is observably reduce and consistency of echo mosaics is improved.