| 成都地区重浮尘天气过程多源观测分析 |
| Multi-source Observation Analysis of Severe Dust Weather Process in Chengdu |
| 投稿时间：2024-08-14 修订日期：2024-12-30 |
| DOI：10.19316/j.issn.1002-6002.2025.01.07 |
| 中文关键词: 浮尘 回流输送 气溶胶消光系数 退偏振比 成都 |
| 英文关键词:floating dust backward transport aerosol extinction coefficient depolarization ratio Chengdu |
| 基金项目:成都市气象局2024年度业务技术研究重点课题(2024-14) |
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| 通讯作者:徐栋夫* 成都市气象局, 四川 成都 611130 |
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| 中文摘要: |
| 利用气溶胶激光雷达和风廓线雷达监测数据,结合地面环境气象观测资料、ERA5再分析资料以及HYSPLIT后向轨迹模型模拟结果,分析了2024年2月19—20日成都一次严重浮尘天气过程的特征及其气象成因。结果表明:①此次浮尘天气过程具有明显的回流传输特征,地面PM10浓度历经了快速增长、高位波动和快速降低3个阶段,其间的PM10浓度峰值为474 μg/m3,最大增速为81 μg/(m3· h),最大降速为86 μg/(m3· h)。②低空急流的动量下传引发并促进了此次浮尘天气过程,大风速核降至750 m以下高度为沙尘输送提供了有利的气象条件,弱东北风回流的维持则促使近地面沙尘不断积累,而较强梯度风输送清洁空气入蓉是此次浮尘天气过程结束的气象成因。③此次浮尘天气过程的整体影响高度位于1 600 m以下,其间呈波动性变化。在主要污染时段内,沙尘气溶胶粒子集中分布在地面至600 m高度层内。白天混合层升高可抬升浮尘影响高度,近地层气溶胶污染随之得到一定程度的缓解,但不能实现有效清除。在浮尘清除阶段可监测到浮尘影响高度出现明显上升,沙尘粒子被吹扬至高空并不断扩散。位于成都冬季主要风向上游的广元、绵阳、德阳以及四川盆地东北部地区,可作为成都市沙尘天气监测预报的重点关注区。 |
| 英文摘要: |
| By using aerosol lidar and wind profile radar monitoring data,combined with surface meteorological observations,groundbased environmental meteorological observations, ERA5 reanalysis datasets and HYSPLIT backward trajectory model, the characteristics of a severe dust weather process in Chengdu on February 19-20,2024 were analyzed. The results showed as follows:1) The dust event in Chengdu exhibited distinct features of backward transport. The PM10 concentration at ground level experienced rapid growth,high-level fluctuations,and rapid decline in three stages. During this period,the peak PM10 concentration reached 474 μg/m3 with maximum increase and decrease rate of 81 μg/(m3·h) and 86 μg/(m3·h) respectively. 2) The downward transfer of momentum from low-level jets triggered this dust event. As the wind speed core descended below 750 m altitude, it provided favorable meteorological conditions for dust transport. The maintenance of weak northeasterly wind led to continuous accumulation of near-surface sand particles while strong gradient wind transport facilitated the dispersion of clean air which ultimately ended the dust event. 3) Overall impact was observed at altitudes below 1600 m with fluctuating changes during the process. During peak pollution periods,sand aerosol particles were concentrated within the layer from ground level to an altitude of 600 m. Diurnal elevation of mixing layers raised the height affected by dust; consequently alleviating near-surface aerosol pollution to some extent but not entirely eliminating it. A rapid removal stage indicated a noticeable increase in dust influence height as particles were dispersed into higher atmospheric levels. The study suggests that areas upstream from Chengdu including Guangyuan,Mianyang,Deyang as well as northeastern parts of Sichuan Basin should be given special attention for monitoring and forecasting dust weather events. |
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