Statistical characteristics of raindrop size distributions observed in East China during the Asian summer monsoon season using 2‐D video disdrometer and Micro Rain Radar data

Abstract

The characteristics of raindrop size distributions (DSDs) and vertical structures of rainfall during the Asian summer monsoon season in East China are studied using measurements from a ground‐based two‐dimensional video disdrometer (2DVD) and a vertically pointing Micro Rain Radar (MRR). Based on rainfall intensity and vertical structure of radar reflectivity, the observed rainfall is classified into convective, stratiform, and shallow precipitation types. Among them, shallow precipitation has previously been ignored or treated as outliers due to limitations in traditional surface measurements. Using advanced instruments of 2DVD and MRR, the characteristics of shallow precipitation are quantified. Furthermore, summer rainfall in the study region is found to consist mainly of stratiform rain in terms of frequency of occurrence but is dominated by convective rain in terms of accumulated rainfall amount. Further separation of the summer season into time periods before, during, and after the Meiyu season reveals that intrasummer variation of DSDs is mainly due to changes in percentage occurrence of the three precipitation types, while the characteristics of each type remain largely unchanged throughout the summer. Overall, higher raindrop concentrations and smaller diameters are found compared to monsoon precipitation at other locations in Asia. Higher local aerosol concentration is speculated to be the cause. Finally, rainfall estimation relationships using polarimetric radar measurements are derived and discussed. These new relationships agree well with rain gauge measurements and are more accurate than traditional relations, especially at high and low rain rates.

Vertical Structures of Typical Meiyu Precipitation Events Retrieved From GPM‐DPR

“…These results, such as larger RR, Z e , D m , and log 10 N w for CP than SP, were similar to the two-dimensional video disdrometer measurements reported in Wen et al (2016). For example, all had normal distributions with near-zero skewness (< 0.9); the mean Z e differences were 0.82 and 1.4 for CP and SP, while the mean D m differences were 0.01 and 0.01, and mean log 10 N w differed by 0.04 and 0.08, all of which were statistically insignificant differences.…”

Diurnal Variation of Meiyu Rainfall in the Yangtze Plain During Atypical Meiyu Years

“…The echo-top height of the Ku-band in this precipitation event was <10 km, and the echo reflectivity was <40 dBZ. The scattering of convective pixels can be divided into two types: One with a larger dBN 0 but smaller D 0 than the stratiform pixels and one with a larger D 0 , corresponding to the shallow precipitation and nonshallow convective precipitation, respectively, in Wen et al (2016). There is generally no bright band for convective precipitation because the melting layer is not uniform.…”

Characteristics of Summer Season Raindrop Size Distribution in Three Typical Regions of Western Pacific

“…Characteristics of DSDs in different continental locations from tropics to midlatitudes along with different disdrometers have been well documented. For example, in Darwin, Australia (Penide, Kumar, et al, ; Penide et al, ; Thurai et al, ), the coast of India (Harikumar et al, ; Radhakrishna et al, ), northeastern Brazil (Tenório et al, ), Singapore (Kumar et al, ), Oklahoma (Cao et al, ), and south and east China (Chen et al, , ; Wen et al, ). Characteristics of DSDs in a few maritime locations are also reported; there were the Tropical Ocean and Global Atmosphere Coupled Ocean‐Atmosphere Response Experiment carried out in Pacific (Atlas et al, ) and the research on the summer season DSD differences between Palau and Taiwan in western Pacific reported by Seela et al ().…”