Abstract

The microphysical characteristics of tropical cyclones vary in different rain regions, which affects not only the dynamic and thermodynamic mechanisms of the typhoon system but also the development of tropical cyclones. This study analyzed the raindrop size distribution (DSD) and the gamma DSD parameters associated with Typhoon Mangkhut using three two-dimensional (2D) video disdrometers from the Longmen Field Experiment Base for Cloud Physics, China Meteorological Administration in Guangdong, China during 16–17 September 2018. According to the observed track and radar reflectivity, this process can be divided into three distinct segments: the outer rainband before landfall (S1), the inner core (S2), and the outer rainband after landfall (S3). The outer rainband mainly produces stratiform rains, while the inner core mainly produces convective rains. The temporal and spatial variations in the rain rate, radar reflectivity, and DSD parameters of the different segments were analyzed and compared at three sites. Although the DSD characteristics are distinctly different in the three segments, the DSD characteristics of the same segment were similar at different sites. In the inner core (S2), the precipitation contains smaller drops (around 0.5 mm) and the concentrations are higher within each size bin compared with those of the other segments, resulting in the maximum rain rate (11.66 mm h−1), radar reflectivity (34.53 dBZ), liquid water content (0.65 g m−3), and number concentration (4.12 mm−1 m−3 on a logarithmic scale) occurring in this segment. The Nw–Dm scatter pairs have maritime-like convection, which increases outward from the inner core (S2). The relationship between the shape (μ) and slope (Λ) was also investigated. The microphysical characteristics determined in this study provide useful information for understanding microphysical precipitation processes and for improving the precision of numerical weather prediction models.

Highlights

  • The raindrop size distribution (DSD) is a key parameter for cloud and precipitation microphysical process analysis, which is essential for creating numerical weather prediction models [1,2].Atmosphere 2020, 11, 975; doi:10.3390/atmos11090975 www.mdpi.com/journal/atmosphereThe variations in the DSD are important to quantitative precipitation estimation (QPE) and forecasting (QPF) based on polarimetric radar [3,4].In the past, conventional measurement techniques, including the momentum method, the flour method, filter paper, raindrop camera, and the immersion method, have been used to collect and determine the DSD parameters artificially

  • When we focused on the probability density function (PDF), we found that the rain rate [18]

  • When we focused on the probability density function (PDF), we found that the majority majority of the raindrop sizes (Dm) were 1–2 mm in three segments

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Summary

Introduction

The raindrop size distribution (DSD) is a key parameter for cloud and precipitation microphysical process analysis, which is essential for creating numerical weather prediction models [1,2]. Based on the 2DVD and C-band polarimetric radar, Chang et al [17] investigated the DSDs and drop shape relations (DSR) of typhoon systems during landfall in the western Pacific. Based on the 2DVD and C-band polarimetric radar data, Wen et al [20] attempted to investigate the DSD and DSR of seven typhoons in China. They found that the DSDs of the seven typhoons differed, the microphysical characteristics of two of the typhoons were similar. 2020, in the range of11,a 975 unit size interval ( ) is calculated as follows:

Data and Methods
Overview of the Typhoon
NationalCenters
16 Sep 2018
The obtained
DSDs Characteristics Derived from the 2DVD Measurements at the Three Stations
Gamma and Parametersofofthe
Section 4.2.
Raindrop Spectra
Findings
Summary
Full Text
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