Variations of Raindrop Size Distribution and Radar Retrieval in Outer Rainbands of Typhoon Mangkhut (2018)

• Published in: Journal of Meteorological Research Vol. 36; no. 3; pp. 500 - 519
• Main Authors: Lyu, Jingjing, Xiao, Huiwen, Du, Yuchun, Sha, Lina, Deng, Yuqing, Jia, Weikai, Niu, Shengjie, Zhou, Yue, Pang, Guqian
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2022; Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD),Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological Administration,Nanjing University of Information Science&Technology,Nanjing 210044%Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD),Key Laboratory for Aerosol–Cloud–Precipitation of China Meteorological Administration,Nanjing University of Information Science&Technology,Nanjing 210044; College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049%Hubei Key Laboratory for Heavy Rain Monitoring and Warning Research,Institute of Heavy Rain,China Meteorological Administration,Wuhan 430205%Climate Center of Guangdong Province,Guangzhou 510080
• Subjects: Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Earth and Environmental Science; Earth Sciences; Geophysics and Environmental Physics; Meteorology; Original Paper; drop size distribution; typhoon; axis ratio; two-dimensional video disdrometer; quantitative precipitation estimation
• ISSN: 2095-6037; 2198-0934
• DOI: 10.1007/s13351-022-1134-2

The evolution of the microphysical properties of raindrops from Typhoon Mangkhut’s outer rainbands as the storm made landfall in South China in September 2018 was investigated. The observations by three two-dimensional video disdrometers deployed in central Guangdong Province were analyzed concurrently. It was found that the radial distribution of the median volume diameter ( D 0 ) and normalized intercept parameter ( N w ) varied in different stages, and that raindrops smaller than 3.0 mm contributed more than 99% of the total precipitation. Considering the characteristics of precipitation in the typhoon outer rainband, a modified stratiform rain (SR)—convective rain (CR) separator line is proposed based on D 0 and N w scatterplots. Meanwhile, an “S—C likelihood index” is introduced, which was used to classify three rain types (SR, CR, and mixed rain). The CR results were highly consistent with those of the improved typhoon precipitation classification method based on rain rate. By calculating effectively the radar reflectivity factor ( Z e ) in the Ku and Ka bands, D 0 — Z e and N w — D 0 empirical relations were thereby derived for improving the accuracy of rainfall retrieval. Among the four quantitative precipitation estimators using S-band dual-polarimetric radar parameters simulated by the T-matrix method, the estimator that adopted the specific differential phase and differential reflectivity was found to be the most effective for both SR and CR.