• 关键词：和田绿洲  沙尘暴  大气污染物  后向轨迹  聚类分析  潜在源贡献因子法

• 基金项目：中国科学院"西部之光"项目（No.Y734341）；新疆维吾尔自治区气象局专项项目（No.DKJJ2019010）

• 艾沙江·艾力
• 中国科学院新疆生态与地理研究所, 荒漠与绿洲生态国家重点实验室, 乌鲁木齐 830011

• 梁菲菲
• 乌鲁木齐市气象局, 乌鲁木齐 830001

• 徐海量
• 中国科学院新疆生态与地理研究所, 荒漠与绿洲生态国家重点实验室, 乌鲁木齐 830011

• 木合塔尔·吾提库尔
• 墨玉县气象局, 墨玉 848100

• 麦麦提艾力·麦麦提敏
• 墨玉县气象局, 墨玉 848100

• 李金
• 中国科学院新疆生态与地理研究所, 荒漠与绿洲生态国家重点实验室, 乌鲁木齐 830011

• 摘要：为了研究来自不同方向的沙尘暴对和田绿洲大气环境质量的影响，本文利用HYSPLIT后向轨迹模型和NCEP的GDAS全球气象要素数据，将和田绿洲西北部的墨玉县城作为模拟受点（37.26°N，79.72°E），计算2016年1月1日—2018年12月31日发生的每一次沙尘天气期间逐日18：00（世界时）36 h后向气流轨迹，轨迹计算起始高度设置为500 m，并结合相应的PM_2.5、PM₁₀、SO₂、NO₂、CO、O₃浓度监测数据进行聚类分析，研究抵达该地区的沙尘暴的主要移动轨迹和污染物输送路径.同时，运用潜在源贡献因子分析法（PSCF）和权重污染轨迹分析法，分析了沙尘暴期间不同气流轨迹对墨玉县污染物浓度的影响，识别大气污染物的潜在源区，揭示不同源区对污染物浓度的贡献差异.结果表明，影响和田绿洲（墨玉县）的沙尘暴主要来自西北（WN）、北（N）、东北（EN）和东（E）4个方向；其中，来自东部的沙尘天气频率最高（60.2%），但主要以浮尘天气为主；扬沙和强沙尘暴主要来自西部方向，54.48%的强沙尘暴和38.53%的扬沙来自西和西北方向.不同沙尘源区和不同传输路径上的沙尘气溶胶对和田绿洲大气环境的影响不一样.沙尘天气期间，大气PM_2.5和PM₁₀的平均浓度相当于无沙尘天气期间的3~5倍，但对SO₂、NO₂、CO、O₃质量浓度的影响不大；由西向东和由北向南的沙尘暴对墨玉县PM_2.5和PM₁₀质量浓度的贡献率最大；由东向西的沙尘暴由于路过和田市和洛浦县等工业污染源区，此簇沙尘暴气团将该区域SO₂、NO₂、CO等污染颗粒携带到墨玉县，因此，东-东南（E-ES）方向的沙尘暴对SO₂、NO₂、CO的贡献率分别为15.56%、20.55%和21.57%.本文定量印证了沙尘暴对和田绿洲大气环境质量的影响，可为绿洲区沙尘暴研究提供参考.

• Abstract：Hetian oasis is one of the severe dust storm affected areas in China. The frequent dust storms have caused harmful effects on the oasis ecosystem, air quality, agriculture, transportation and human health. In this study, the Moyu County which is located at the northwest part of Hetian oasis is selected as study area. To assess the source regions and transport pathway of dust storms, 36h backward trajectories of air masses arriving at the Moyu County in dusty days in the period of 2016—2018 were determined by using Hybrid Single Particle Lagrangian Integrated Trajectory model (HYSPLIT 4). The trajectories were categorized by k-means clustering into 4 clusters which show distinct features in terms of the trajectory origins and the entry direction to the site. The relevant air quality data for each cluster were analyzed by using Potential Source Contribution Function (PSCF) and weighted pollution trajectory analysis to reveal the impact of dust storm from different directions on the air quality. The results show that, the dust storm affecting on Hetian Oasis (Moyu county) mainly comes from four directions: WN, N, E and ES. Among them, the dust storm from the East has the highest frequency (60.2%), but the intensity of dust storm from this site is lower. The strong sandstorm mainly comes from the west, with 54.48% of strong sandstorm coming from the west and northwest direction in study period. During the dusty days, the average concentration of PM_2.5 and PM₁₀ in the atmosphere is 3~5 times of that in the non-dusty days, but the contribution of dust particles on the concentration of SO₂, NO_2, CO and O₃ is unremarkable. There are significant differences in the contribution of dust storm from different direction on different pollutant's concentration. Higher concentration levels of SO₂, NO₂ and CO were mostly associated with cluster EN-E and cluster E-ES which had trajectories passing over the anthropogenic source regions while higher concentrations of PM₁₀ and PM_2.5 were mainly observed in cluster N-N and cluster WN-W which had a longer pathway over the shifting sand desert area.

• Key words：Hetian Oasis  dust storm  air pollutants  backward trajectory  cluster analysis  potential source contribution function

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