Statistical Characteristics of Raindrop Size Distributions and Parameters in Central China During the Meiyu Seasons

Abstract

The rain parameters derived from the laser OTT second-generation Particle Size Velocity (Parsivel 2), the two-dimensional video disdrometer (2DVD), and DZZ5 tipping-bucket rain gauge (RG) during the Integrative Monsoon Frontal Rainfall Experiment (IMFRE) in summer 2018 are compared. The total rainfall amounts observed by Parsivel, 2DVD, and RG during IMFRE were 178.07, 176.76, and 182.5 mm, while their total rainy hours were 113, 113, and 90. The mean D m (mass-weighted mean diameter) and LWC (liquid water content) values derived from Parsivel and 2DVD were 1.03 and 1.01 mm and 0.247 and 0.223 g m −3. The rainy samples from six Parsivel sites over the middle reaches of the Yangtze River during the 2016-2018 Meiyu seasons have been collected and analyzed. The occurrence frequencies for rain rates (RR) < 5 and >10 mm hr −1 were 83.9% and 7.4%, respectively, but they contributed 30.5% and 52.1% of the total accumulated rainfall. Compared with the results over the lower reaches of the Yangtze River, the total accumulated rainfall percentages for RR < 5 mm hr −1 and RR > 10 mm hr −1 observed at XN site were higher and lower, respectively. The stratiform rain (SR) raindrop size increases with RR over both the middle and lower reaches, whereas the N w values over the middle reaches are much higher. Opposite to the SR results, the convective rain (CR) raindrops from this study are larger, while their N w values are similar to one another. For gamma-type-size distribution, the μ − λ and Z − R relations are strongly dependent on geographical location.

Characteristics of Raindrop Size Distributions during Meiyu Season in Mount Lushan, Eastern China

“…So the second peak of 10 in Mount Lushan can be affected jiontly by shallow rain as well as the elevation of mountain topography. Moreover, the first peak in the present study differs from some Meiyu studies (Fu et al, 2020;Wen et al, 2016). The higher standard deviation and skewness also indicate significantly higher RSD variability s in Mount Lushan during the Meiyu season.…”

“…Furthermore, the frequency of 10 exhibits a second peak. This was also reported and attributed to shallow rain by Wen et al (2016) and Fu et al (2020). In the present study, the elevation of Mount Lushan will result in insufficient coalenscence and thus reduce the concentration of large raindrop.…”

“…More recently, Fu et al (2020) studied RSD characteristics in central China, and demonstrated different and values and different − and − relationships.…”

Characteristics of Rain-Induced Attenuation over Signal Links at Frequency Ranges of 25 and 38 GHz Observed in Beijing

“…The DSD data set then was classified into two categories, convective and stratiform rainfall types. The classification of rain types in this study was mainly based on disdrometer data using the method described by Bringi et al [45] and adopted in many studies [45,46]. Therefore, for at least 10 consecutive oneminute rain samples, if the average rainfall rate was >0.5 mm/h and the standard deviation was <1.5 mm/h, then the sample was classified as stratiform rain; if the average rainfall rate was >5 mm/h and the standard deviation was >1.5 mm/h, then it was classified as convective rain.…”

Spatial and Temporal Variability in Rainfall Erosivity Under Alpine Climate: A Slovenian Case Study Using Optical Disdrometer Data

“…The applications of optical disdrometers can be traced back over several decades, e.g., field measurements in Barcelona between January 1994 and December 1995 (Cerro et al, 1998). Some recent studies using the optical type of disdrometers to study DSD and estimating rainfall erosivity include, among others, a study at Palermo, Sicily, in the periods 2006-2012 (Carollo and Ferro, 2015) and 2006(Carollo et al, 2016, in the Lazio region in central Italy in the period June 2010-April 2015 (Mineo et al, 2019), in Cherrapunji in Northeast India from May to October 2017 (Murata et al, 2020), and in Central China in summer 2018 (Fu et al, 2020). Not many studies have evaluated disdrometer data not only as point measurements but rather in terms of spatial variability.…”