Combining disdrometer, microscopic photography, and cloud radar to study distributions of hydrometeor types, size and fall velocity

Microphysical Characteristics of Winter Precipitation in Eastern China from 2014 to 2019

“…In this study, winter precipitation data from February 2014 to February 2019, observed by an OTT PARSIVEL disdrometer [10,23] at a station (31.97 • N, 118.81 • E, 32 m above sea level) in Nanjing, eastern China, were used (as shown in Figure 1). Nanjing is located in the north subtropical monsoon climate zone, which has abundant precipitation every year from approximately mid-November into winter.…”

“…To better describe PSD, we need to fit it with appropriate functions. The commonly used function is the three-parameter gamma function due to its universality [10,32]…”

“…Common methods for distinguishing precipitation types include using Formvar slides to collect particles and manually determine the types with a microscope [10,[39][40][41] or automatically judging the precipitation particle pictures taken by combining with an image recognition algorithm [7,12]. In addition, because the V-D relationships between different types of precipitation are obviously different, the V-D function fitted by 1-min average data can also be used to distinguish precipitation types [11,42,43].…”

“…The mass-size and velocity-size relationships of solid precipitation particles determine the correctness of Numerical Weather Prediction (NWP) model parameterization, which has an impact on the prediction of precipitation location, precipitation intensity and start and end times [7][8][9]. Whether passive or active, ground-based or space-based electromagnetic propagation models are sensitive to the shape and density of solid precipitation particles, and a reasonable description of precipitation microphysical characteristics is essential to the inversion algorithm of precipitation intensity based on remote sensing [10][11][12]. The erosion effect of precipitation on soil is closely related to its type and the particle size distribution (PSD), which is very important for the flood control and water fixation abilities of ecosystems [13][14][15].…”

“…Zhang et al [17] observed several weather processes involving solid precipitation using a 2-dimensional video disdrometer (2DVD) and compared the theoretically calculated polarization variables with the radar-measured values to verify the effectiveness of the density correction algorithm in Oklahoma. Jia et al [10] used a PARticle SIze VELocity (PARSIVEL) disdrometer and microscopic photography to analyze the fall velocity and PSD of rain, graupel, snow and mixed-phase precipitation particles in northern China.…”