中国气象科学研究院王改利团队报道了青藏高原东南部不同天气形势下的DSD特征。相关论文于2024年9月10日发表在《大气科学进展》杂志上。

据介绍，Mêdog是青藏高原降雨量最大、海拔最低的地区。在不同的天气形势下，雨滴粒径分布(DSD)和与降雨相关的微物理过程，在热力上表现出不同的特征。

本研究采用了一种客观的分类方法，将影响Mêdog强降水的天气分为四种类型：西南气流(SWA)、南支槽(SBT)、强斜压(IBC)和地形强迫降水(TFP)。在这些模式中，SBT模式显示出最低的小雨滴浓度。与此相反，TFP型表现出最大的大雨滴浓度和最宽的DSD谱，这可归因于该地区对流活动频繁。结果表明，与其他三种天气型相比，TFP型表现出更大的Dmand和更高的R。对于层状降水，四种天气类型的Dm差异可以忽略不计。

在SWA (IBC)模式中观测到最大(最小)平均lg(NW)值。在对流降雨方面，IBC模式观测到较大的雨滴和较低的浓度，可以认为是大陆性降雨，而SWA模式观测到高浓度的小雨滴，类似于海洋性降雨。就导出的关系方面，四种天气型之间的Dm-R和μ-Λ关系有显著差异。此外，研究人员还从天气型的角度分析了DSD的日变化。这些发现可以提高人们对暴雨事件微物理过程的认识，并为数值模式的微物理参数化提供参考。

附：英文原文

Title: DSD Characteristics with Different Synoptic Patterns in the Southeastern TP Region

Author: Ran Li, Wang Gaili, Jisong Sun, Lang SUO, Ting WANG

Issue&Volume: 2024-09-10

Abstract: Mêdog has the highest rainfall and lowest elevation on the Tibetan Plateau. The drop size distribution (DSD) and microphysical processes associated with rainfall usually exhibit different characteristics under different synoptic patterns. In this study, an objective classification method is used to categorize the synoptic patterns that affect heavy rainfall in Mêdog into four patterns: southwest airflow (SWA), southern branch trough (SBT), intense baroclinicity (IBC), and terrain-forced precipitation (TFP). Among these patterns, the SBT pattern exhibits the lowest concentration of small raindrops. In contrast, the TFP pattern exhibits the highest concentration of large raindrops and the widest DSD spectrum, which can be attributed to the frequent convective activities in this area. As a result, compared with those of the other three synoptic patterns, the TFP pattern exhibits a larger Dmand higher R. For stratiform rainfall, the difference in Dm among the four synoptic patterns can be neglected. The largest (smallest) average lg(NW) value is observed in the SWA (IBC) pattern. Regarding convective rainfall, larger raindrops and lower concentrations are observed in the IBC pattern and can be considered continental-like rainfall, while high concentrations of small raindrops are observed in the SWA pattern, similar to maritime-like rainfall. In terms of the derived relationships, there are significant differences in the Dm–R and μ–Λ relationships among the four synoptic patterns. In addition, the diurnal variation in the DSD is analyzed in terms of the four synoptic patterns. These findings can improve the understanding of the microphysical processes of heavy rainfall events and provide a reference for microphysical parameterizations of numerical models.

DOI: 10.1007/s00376-024-4048-3

Source: http://www.iapjournals.ac.cn/aas/en/article/doi/10.1007/s00376-024-4048-3viewType=HTML