沙尘天气事件作为一种危害性极大的灾害天气, 对我国西北干旱区生态环境影响显著。 借助于地面实测颗粒物数据、 MODIS影像数据、 OMI传感器影像数据、 CALIPSO激光雷达数据, 采用HYSPLIT模式对我国西北地区2016年一次典型沙尘事件时空演变特征进行研究。 首先, 基于PM2.5/PM10指数判断西北地区典型城市大气污染源性质以及污染情况; 然后, 利用MODIS影像MCD19-A2数据产品-气溶胶光学深度AOD数据、 OMI-Aura L3级OMAEROe数据产品-紫外吸水性气溶胶指数AAI数据和CALIPSO-Level1级数据, 分析大气气溶胶中沙尘水平空间分布特征; 最后, 借助HYSPLIT模式模拟沙尘气流后向轨迹, 确定区域内沙尘传送路径。 研究结果显示, 西北地区典型城市中西宁、 兰州、 银川在2016年4月30日—5月1日前后PM10指数均超过200 μg·m-3, PM2.5/PM10均小于0.6, 且处于较低值, 这表明是由于自然污染源影响导致空气中可吸入颗粒物含量上升, 可推测此次为沙尘暴事件影响; 大气气溶胶在沙尘事件发生期间呈现出明显水平变化特征, 沙尘事件起源于南疆盆地, 在5月1日至5月4日持续影响新疆南部和中部地区, 青海、 甘肃、 宁夏以及陕西部分地区也受到影响; 根据其变化可知, 塔克拉玛干沙漠是本次沙尘天气事件气溶胶污染形成的中心, 此次沙尘暴事件影响范围主要有新疆南部盆地和中部以及青海省北部地区; 通过对气流轨迹模拟结果来看, 2016年4月30日—5月1日沙尘暴事件通过偏西型路径主要影响新疆以及青海部分地区, 经分析可得其沙尘物质可能来源于南疆盆地、 新疆北部位于准噶尔盆地内部古尔班通古特沙漠以及境外哈萨克斯坦等地区。 这些研究结果将为抑制西北地区沙尘源地起沙过程、 保护生态环境可持续发展提供重要科学依据。

As a kind of disastrous weather with great harmfulness, sandstorm event significantly impacts the ecological environment in Northwest China. This study, it is to explore the spatial-temporal evolution of a typical dust event in northwest China in 2016 based on ground-measured particulate matter data, MODIS data, OMI sensor data and CALIPSO LiDAR data. Firstly, the characteristics and pollution situation of typical urban air pollution sources in Northwest China were determined based on PM2.5/PM10 index. Then, the spatial distribution characteristics of dust levels in atmospheric aerosols were analyzed using MODIS image MCD19-A2 AOD data, OMAEROe data product OMAEROe data product AAI data and CALIPSO-Level1 data. Finally, the backward trajectory of dust flow was simulated by the HYSPLIT model to determine the dust transport path in Northwest China. The results showed that the PM10 index of Xining, Lanzhou and Yinchuan was more than 200 μg·m-3 from April 30th to May 1th, 2016, and their PM2.5/PM10 value was less than 0.6, which was at a low level, indicating that the content of inhalable particulate matter in the air increases due to the influence of natural pollution sources. It could be inferred that this was the influence of the sandstorm event. Aerosol showed obvious horizontal variation during the sandstorm event. The sandstorm originated from the Southern Xinjiang Basin and continuously affected southern and central Xinjiang from May 1th to May 4th. In addition, Qinghai, Gansu, Ningxia and some parts of Shaanxi were also affected. According to its spatial variation, the Taklimakan Desert was the center of the formation of aerosol pollution in this sandstorm event. The sandstorm event mainly affected the southern basin and central Xinjiang, and the northern part of Qinghai Province. It could be seen from the simulation results of the air flow track that the sandstorm event from April 30th to May 1th, 2016, mainly affected Xinjiang and some areas of Qinghai through the westward path. What is more, the sandstorm material might have come from Southern Xinjiang basin and the Gurbangut Desert in the inner Junggar Basin of northern Xinjiang and Kazakhstan outside China. These results would provide an important scientific basis for suppressing the process of dust generation and protecting the sustainable development of an ecological environment in Northwest China.