Structure of dust and air pollutant outflow over East Asia in the spring
Structure of dust and air pollutant outflow over East Asia in the spring
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DOI：
10.1029/2010gl044776
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发表时间：
2010-10
影响因子：
5.2
通讯作者：
S. Itahashi;K. Yumimoto;I. Uno;K. Eguchi;T. Takemura;Y. Hara;A. Shimizu;N. Sugimoto;Zhaoyan Liu
中科院分区：
文献类型：
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作者：
S. Itahashi;K. Yumimoto;I. Uno;K. Eguchi;T. Takemura;Y. Hara;A. Shimizu;N. Sugimoto;Zhaoyan Liu
通过地面/空间激光雷达观测和数值模式的协同分析，研究了亚洲沙尘和空气污染物的春季外流。我们确定了两个突出的外流模式，其发生频率。模式I是在一个典型的暖扇区内引起的，该暖扇区将尘埃颗粒提升到自由对流层中，两个连续的低压系统的存在起了重要作用。第二种模式是“冷锋后”爆发。模式I对流层内的层结较弱（位温梯度为10.2 ~ 3.4 K/km），大部分沙尘层（水平高度1500-2000 km，垂直高度2.5 ~ 4 km）未与污染物混合。模式II的特点是由一个强大的分层的105 K/km的灰尘和污染物被困和混合的PBL内，形成“污染”的灰尘。在6起大规模粉尘/污染物暴发中，只有2起属于模式I。
Springtime outflow of Asian dust and air pollutants was investigated by a synergetic analysis of ground‐based/space‐borne Lidar observations and numerical models. We identified two prominent outflow patterns, and its occurrence frequency. Pattern I was induced within a typical warm‐sector which lifted up dust particles into the free troposphere, and the existence of two sequential low‐pressure systems played an important role. Pattern II was a ‘behind cold front’ outbreak. Atmospheric stratification was significantly different; Pattern I had weak stratification within the troposphere (potential temperature gradient of ∼2–3.4 K/km), and most of elevated dust layer (typically horizontally 1500–2000 km, vertically 2.5–4 km AGL) remained unmixed with pollutants. Pattern II was characterized by a strong stratification of ∼5 K/km; dust and pollutants were trapped and well mixed within the PBL, forming ‘polluted’ dust. Among the six cases of large‐scale dust/pollutants outbreaks, only two cases are belonged to Pattern I.