基于机器学习的河西地区沙尘特征反演和传输通量研究

Study on dust characteristics inversion and transmission flux in in the Hexi region based on machine learning

摘要:

为揭示河西地区沙尘污染的时空演变规律及其传输机制,本研究基于地基遥感垂直观测系统的连续监测数据,包括气溶胶激光雷达、L波段风廓线仪和微波辐射计的观测结果,并结合机器学习算法和HYSPLIT模型,对2023年3月13日至22日的典型沙尘过程进行全面分析。研究结果表明,干暖气象条件及短时大风有利于沙尘的发生与传输,期间共观测到四轮沙尘过程。机器学习模型能够实现颗粒物浓度垂直分布的高精度反演,进一步分析发现,第一轮和第二轮沙尘过程呈现显著的垂直分层特征,第三轮沙尘过程中颗粒物主要聚集于低空区域,而第四轮沙尘传输强度大,高浓度颗粒物从地面至高空均匀分布。结合传输通量与后向轨迹的分析表明,酒泉市西部的新疆地区是重要沙源地,对区域强沙尘天气和高空沙尘传输具有显著影响；东北部的内蒙古地区亦为重要沙源地,但因高空西风为主导,仅通过低空东风对酒泉市沙尘污染状况施加影响。

Abstract:

To reveal the spatiotemporal evolution patterns and transport mechanisms of dust pollution in the Hexi region, this study utilized continuous monitoring data from a ground-based remote sensing vertical observation system, including aerosol lidar, L-band wind profiler, and microwave radiometer. Machine learning algorithms and the HYSPLIT model were employed to comprehensively analyze a typical dust event occurring from March 13 to March 22, 2023. The results indicated that dry and warm meteorological conditions combined with short-term strong winds facilitated the occurrence and transport of dust, with four dust events observed during this period. The machine learning model achieved high-accuracy inversion of the vertical distribution of particulate matter concentrations. The analysis revealed significant stratification in the first and second dust processes, while particulate matter mainly accumulated in the lower atmosphere during the third process. The fourth dust process exhibited strong transport intensity, with high concentrations of particulates uniformly distributed from the surface to high altitude. By analyzing transmission fluxes and backward trajectories, it was found that the Xinjiang region west of Jiuquan is a major dust source, contributing to regional severe dust weather and high-altitude dust transport. Additionally, the Inner Mongolia region to the northeast is also an important source area, but its impact on Jiuquan was limited to the lower atmosphere due to the dominance of upper-level westerly winds.