高原地区拉萨贡嘎机场短时内两次强沙尘过程气象条件及来源对比分析

A Comparative Analysis of Meteorological Conditions and Sources of Two Strong Sand and Dust Processes within a Short Time at Lhasa Gonggar Airport in the Plateau Region

摘要: 本研究针对2023年冬末春初拉萨贡嘎机场两次强沙尘过程(2023年2月11日~12日、3月30日~31日)开展对比分析，结合气象观测、环流背景分析、物理量场与HYSPLIT后向轨迹–浓度权重模拟，揭示其成因与源区贡献差异。结果表明，两次过程均发生在高原西风急流增强背景下，PM₁₀峰值分别达960 μg·m⁻²和810 μg·m⁻²，能见度降至百米级。2023年2月11日~12日沙尘过程受高纬度冷涡东移主导，急流更强，动力抬升显著，沙尘以跨境远距离传输为主，境外源贡献突出；2023年3月30日~31日沙尘过程则主要受西风槽和高压脊南压影响，沙尘更多源于西藏中西部近源区，垂直扩散弱导致污染物持续累积。垂直结构上，两次过程中低层辐散–中层辐合的配置均有利于沙尘垂直混合。基于沙尘来源和传输机制差异，建议强化跨境沙尘监测预警与区域联防联控，提升机场应急响应能力，以保障高原航空安全与空气质量。

Abstract: This study conducts a comparative analysis of two strong sand and dust events at Lhasa Gonggar Airport in late winter and early spring of 2023 (February 11~12 and March 30~31), combining meteorological observations, circulation background analysis, physical quantity fields, and HYSPLIT backward trajectory-concentration weight simulations to reveal their causes and differences in source contributions. The results show that both events occurred under the background of enhanced westerly jet stream over the plateau, with PM₁₀ peaks reaching 960 μg·m⁻² and 810 μg·m⁻² respectively, and visibility dropping to the hundred-meter level. The sand and dust event from February 11~12, 2023, was dominated by the eastward movement of a high-latitude cold vortex, with a stronger jet stream and significant dynamic uplift, and the dust was mainly from long-distance cross-border transport, with significant contributions from foreign sources; the sand and dust event from March 30~31, 2023, was mainly influenced by the west wind trough and the southward pressure of the high-pressure ridge, with dust mainly originating from the near-source areas in the central and western parts of Xizang, and weak vertical diffusion leading to the continuous accumulation of pollutants. In terms of vertical structure, the configuration of low-level divergence and mid-level convergence in both events was conducive to the vertical mixing of sand and dust. Based on the differences in the sources and transport mechanisms of sand and dust, it is suggested to strengthen cross-border sand and dust monitoring and early warning, as well as regional joint prevention and control, and enhance the airport’s emergency response capabilities to ensure aviation safety and air quality on the plateau.