Comparative Analysis of Raindrop Size Distribution Retrieval Techniques Based on Dual Polarization Radar

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  • 1. College of Electronic EngineeringChengdu University of Information TechnologyChengdu 610225SichuanChina
    2. State Key Laboratory of Severe Weather Meteorological Science and TechnologyChinese Academy of M eteorological SciencesBeijing 100081China
    3. Key Laboratory for Atmospheric SoundingChina Meteorological AdministrationChengdu 610225SichuanChina
    4. Institute of Plateau MeteorologyChina Meteorological AdministrationCMA/ Heavy Rain and Drought-Flood
    Disaster in Plateau and Basin Key Laboratory of Sichuan Province
    Chengdu 610072SichuanChina

Online published: 2025-07-22

Abstract

Accurate retrieval of raindrop size distributionsDSDsbased on dual-polarization radar can provide substantial data for the study of precipitation microphysical properties on a large scale. In order to further im‐ prove DSDs retrieval accuracythis study proposes a new double-moment normalization method based on the sixth and seventh momentsM6M7 method),comparing it with the third and sixth moments methodM3M6 methodand the constrained Gamma model DSD retrieval methodC-G methodfrom three perspectivesover‐ all resultsdifferent rainfall intensitiesand different rainfall particle sizes. Utilizing data from six rainfall events observed by dual-polarization radar and surrounding disdrometers at Heyuan station between May and June 2022the retrieval results of each algorithm were analyzed. The results demonstrate that during light rain 0 mm·h-1<R≤5 mm·h-1),the M6M7 method exhibits the smallest parameter biases among the three methods. As rainfall intensity increasesbiases for most parametersexcept for the increase of liquid water contentLWCand rainfall rateR))remain relatively stablewith M6M7 consistently showing the lowest biases across different particle sizes and minimal fluctuation with the increase of particle size. Compared with M6M7 methodthe M3M6 method incorporates specific differential phase shift on propagationKdpfor retrieval. Although Kdp is noise-sensitiveit has good quality in heavy rainR>30 mm·h-1),resulting in smaller estimation biases for intense rainfall events and a decreasing trend in bias with larger particle sizesexcluding LWC and R. For moderate rain5 mm·h-1<R≤30 mm·h-1),the C-G method shows small median deviations yet significant fluctuations in certain parameters. With the increase of rainfall intensity and particle sizeits biases shows a trend of first decreasing and then increaseaccompanied by pronounced relative bias instability. Comprehensive evaluation results demonstrate that the M6M7 method consistently maintains median deviations approaching 0 across all DSD parameterswhile exhibiting significantly tighter error fluctuation ranges. In marked contrastboth the M3M6 method and C-G method display substantially wider bias variabilitywith their error distributions spanning broader numerical ranges and demonstrating less stable performance characteristics. The newly proposed M6M7 method technique demonstrates advantages over traditional approachesexhibiting enhanced comprehensive retrieval capabilities with regard to both accuracy and stabilityparticularly excelling in light-to-moderate rainfall with consistent accuracy. The M3M6 method proves more effective for heavy rain and stormswhile the C-G method demonstrates unstable retrieval characteristics. The final section demonstrates the retrieval performance of the algorithm integrating both M6M7 and M3M6 methodsverifying its capability to further improve raindrop size distribution retrieval accuracy.

Cite this article

ZENG Jing, ZHANG Yang, SU Debin, DONG Yuanchang . Comparative Analysis of Raindrop Size Distribution Retrieval Techniques Based on Dual Polarization Radar[J]. Plateau Meteorology, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2025.00069

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