中国科学院大气物理研究所吕达仁等人的最新研究，探明了基于西藏羊八井二维视频雨滴测量仪（2DVD）长期观测的降水微观物理特征。相关论文于2024年1月25日发表于国际顶尖学术期刊《大气科学进展》杂志上。

据介绍，雨滴尺寸分布(DSD)对提高青藏高原(TP)雷达定量降水估算精度起着重要作用。然而，该地区明显缺乏长期、高分辨率的观测资料。

为了解决这一问题，研究人员利用2DVD的长期观测结果，来改进雷达和基于卫星的算法，以量化青藏高原周边地区的降水。据观察，弱降水(R <1 mm h^-1)占总降水时间的86%，而小雨滴(D <2 mm)占雨滴总数的99%。DSD的平均光谱宽度随降雨量的增加而增大。研究分析了五种不同降雨速率下，对流和层状降水的DSD特征，结果表明羊八井(YBJ)对流降水具有类似海洋降水的特征。

研究人员推导了伽马DSDs的斜率Λ与μ之间的限制关系。此外，研究建立了等效直径与雨滴轴比之间的关系，发现TP上的雨滴更接近球形。最后，在DSD统计结果的基础上，研究人员改进了双频降水雷达雨量反演算法在TP地区的应用。

附：英文原文

Title: Microphysical Characteristics of Rainfall Based on Long-Term Observations with 2DVD in Yangbajing, Tibet

Author: Ming LI, Yongheng BI, Yonghai SHEN, Yinan Wang, Ciren Nima, Tianlu CHEN, Daren Lu

Issue&Volume: 2024-01-25

Abstract: Raindrop size distribution (DSD) plays a crucial role in enhancing the accuracy of radar quantitative precipitation estimation in the Tibetan Plateau (TP). However, there is a notable scarcity of long-term, high-resolution observations in this region. To address this issue, long-term observations from a two-dimensional video disdrometer (2DVD) were leveraged to refine the radar and satellite-based algorithms for quantifying precipitation in the hinterland of the TP. It was observed that weak precipitation (R < 1 mm h^-1) accounts for 86% of the total precipitation time, while small raindrops (D < 2 mm) comprise 99% of the total raindrop count. Furthermore, the average spectral width of the DSD increases with increasing rain rate. The DSD characteristics of convective and stratiform precipitation were discussed across five different rain rates, revealing that convective precipitation in the Yangbajing (YBJ) exhibits characteristics similar to maritime-like precipitation. The constrained relations between the slope Λ and μ, and of gamma DSDs were derived. Additionally, we establish a correlation between the equivalent diameter and drop axis ratio found that raindrops on the TP are closer to spherical shapes. Lastly, the application of the rainfall retrieval algorithms of the dual-frequency precipitation radar in the TP is improved based on the statistical results of the DSD.

DOI: 10.1007/s00376-024-3299-3

Source: http://www.iapjournals.ac.cn/aas/en/article/doi/10.1007/s00376-024-3299-3viewType=HTML