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The measurement of accurate full drop size distribution (DSD) is critical for its precise modeling and hydrometeorological application. However, its measurement hinders from instrumental limitation. We explored a way of constructing full DSDs by combining the 2D-Video Distrometer (2DVD) and Meteorological Particle Spectrometer (MPS) measurements based on instrumental uncertainty statistics, while other existing methods use a fixed critical diameter and weighting. First, the median relative bias (RB) of number concentration for each diameter between the two distrometers is used to determine the diameter range of their merging. Second, the weighting factors within the range were derived from normalized standard deviations of MPS and 2DVD number concentration by diameter during quasi-homogeneous microphysical process. The accuracy of derived full DSD is verified with the rainfall rate (R) and radar reflectivity (Z) from other independent instruments such as PLUVIO and Precipitation Occurrence Sensor System (POSS) that provide the best possible reference of R and Z. The new method is superior to the existing methods, providing relatively lower error statistics during summer rainfall events in 2022. Additionally, the impact of the new method is analyzed on DSD variability using double-moment scaling normalization to derive a stable generic function. Four different triple-moment normalization methods are also employed to describe the reduction of DSD variability. The results demonstrate that the new full DSD significantly reduces DSD variability and better provides stable generic function of DSDs. 

Raindrop size distributions (DSDs) play a key role in revealing the underlying physical processes of rainfall. This study investigates the characteristics of the DSDs in Great Britain (GB) using data collected from eleven Thies laser precipitation monitors (LPMs) between 2017 and 2019. Around one million one-minute raindrop samples were fitted to a normalized gamma drop distribution model. This study examines the DSD characteristics from both temporal (seasons) and spatial (geography and topography) perspectives, considering different rain types (stratiform and convective) and rain rate clusters. The results indicate that the average mass-weighted mean diameter and the average normalized intercept parameter are influenced by geographical and atmospheric conditions. The tends to be lower and is higher in the western and hilly regions, with the opposite pattern observed over the eastern plain of GB. Both parameters are strongly correlated with rain rate. Compared to subtropical/tropical regions, stratiform rain in GB exhibits smaller and larger , while the characteristics of convective rain align with the maritime-like cluster. Significant differences in are observed between stratiform (0.78–1.00 mm) and convective (1.30–1.74 mm) rain, with both showing a significant negative linear correlation with . Moreover, extreme convective events show distinct seasonality, with larger and lower during the warm season. Furthermore, a bimodal distribution is observed for in light rain events over western and hilly regions, highlighting the complexity of microphysical processes associated with small raindrops. The characteristics of DSDs observed in this study provide valuable insights for future investigations into GB's precipitation formation and quantitative precipitation estimation using weather radar. 

The feasibility of retrieving the moments of rain drop size distributions from S-band polarimeteric weather radars is examined using radar observations and data from ground instrumentations for a relatively widespread event in Northern Colorado, USA. In a previous study, the same event had been analyzed using X-band radar data. The retrieval method for X-band was modified based on S-band simulation results. Our analyses show that good accuracy for the retrievals can be obtained if there is appreciable differential reflectivity as well as specific differential propagation phase at S-band. 

A method to retrieve the moments of rain drop size distributions (DSDs) from X-band dual-polarimetric radars is tested using data from a warm rain event that occurred near Incheon, Republic of Korea. The method involves the use of attenuation-corrected radar reflectivity ( Zh ) for horizontal polarization, attenuation-corrected differential reflectivity ( Zdr ), and the specific attenuation ( Ah ) for horizontal polarization. The method was previously tested for an event in Greeley, CO, USA, and had resulted in very encouraging results. In this article, we apply the same method to an isolated warm rain cell and examine the height profiles of the retrieved moments. We show that the application of the method results in very plausible results in terms of the dominant microphysical processes associated with warm rain events.