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郝峰, 徐曼, 谷雨, 等. 2024. 基于激光雷达观测的呼伦贝尔一次沙尘过程分析[J]. 气候与环境研究, 29(2): 205−215. doi: 10.3878/j.issn.1006-9585.2023.23096
引用本文: 郝峰, 徐曼, 谷雨, 等. 2024. 基于激光雷达观测的呼伦贝尔一次沙尘过程分析[J]. 气候与环境研究, 29(2): 205−215. doi: 10.3878/j.issn.1006-9585.2023.23096
HAO Feng, XU Man, GU Yu, et al. 2024. Analysis of a Dust Transport Event in Hulunbuir Based on Coherent Doppler Wind Lidar [J]. Climatic and Environmental Research (in Chinese), 29 (2): 205−215. doi: 10.3878/j.issn.1006-9585.2023.23096
Citation: HAO Feng, XU Man, GU Yu, et al. 2024. Analysis of a Dust Transport Event in Hulunbuir Based on Coherent Doppler Wind Lidar [J]. Climatic and Environmental Research (in Chinese), 29 (2): 205−215. doi: 10.3878/j.issn.1006-9585.2023.23096

基于激光雷达观测的呼伦贝尔一次沙尘过程分析

Analysis of a Dust Transport Event in Hulunbuir Based on Coherent Doppler Wind Lidar

  • 摘要: 基于测风激光雷达和地面常规观测资料,借助机器学习算法以及HYSPLIT(Hybrid Single-Particle LagrangianIntegrated Trajectory)模型分析了发生在呼伦贝尔的一次典型的沙尘天气过程。研究表明,本次沙尘起始时南风突增,风向转西南偏南风后风速降低,传输减弱,当风向转西风时,沙尘传输增强,在西风降低后沙尘传输结束。沙尘传输期间,湍流运动偏弱,混合层高度抬升受限。借助机器学习分粒径计算发现,沙尘前期传输以粗颗粒为主,后期粗、细颗粒物均有明显增长。不同传输时期粒径的不同,暗示沙尘的源可能发生变化,后向轨迹揭示沙尘传输前期来自蒙古国西北部,经过我国锡林郭勒后北上到达呼伦贝尔;而后期沙尘是从俄罗斯南部直接进入呼伦贝尔。最后研究发现,沙尘前至起始时刻,总传输通量对沙尘的响应早于地面颗粒物浓度变化,且沙尘期间总传输通量值显著高于沙尘前和沙尘后。因此,总传输通量变化以及阈值设定可为沙尘预警的新参考指标。

     

    Abstract: Based on coherent Doppler wind lidar and ground-based conventional observational data, a typical dust transport event occurring in Hulunbuir, China, was analyzed herein using machine learning and the HYSPLIT (Hybrid Single-Particle LagrangianIntegrated Trajectory) model. The study revealed that the dust transport event started with a sudden increase in southerly wind. Subsequently, the wind direction shifted to south–southwest, resulting in wind speed and dust transport reductions. However, when the wind shifted to westerlies, dust transport again intensified. The transport of dust ceased after the westerly wind speed decreased. During the dust transport period, turbulence was relatively weak, and the mixing-layer height remained limited, particularly when compared to conditions without the influence of dust. Machine learning–based particle size calculations indicated that PM10 dominated the early dust transport phase, and both PM10 and PM2.5 showed substantial growth in the later phase. This divergence in particle sizes across different transport periods suggested a potential change in dust sources. The HYSPLIT model revealed that the early phase of dust transport started from northwestern Mongolia, passing through the Xilingol League in China before reaching Hulunbuir. In the later phase, dust directly entered Hulunbuir from the southern regions of Russia, escalating dust pollution. Finally, the study found that the response of total mass flux to dust occurred earlier than the change in ground-level particulate concentration from the pre-dust phase to the onset. Furthermore, total mass flux values during dust events were significantly higher than those before and after the dust events. Therefore, total mass flux variations and threshold establishment can serve as novel indicators for dust events in early warning systems.

     

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