Meteorological conditions for the persistent severe fog and haze event over eastern China in January 2013
Meteorological conditions for the persistent severe fog and haze event over eastern China in January 2013
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DOI：
10.1007/s11430-013-4774-3
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发表时间：
2014-01-01
影响因子：
5.7
通讯作者：
Zhang RuoNan
中科院分区：
文献类型：
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作者：
Zhang RenHe;Li Qiang;Zhang RuoNan
2013年1月，我国东部地区发生了一次强度强、持续时间长、覆盖范围广的严重雾霾天气（FHE）。本研究通过对2013年1月的大气背景场和逐日演变进行诊断，探讨了这次FHE的气象条件。结果表明，2013年1月存在弱东亚冬季风。中国东部地区，对流层中下层的异常偏南风有利于更多的水汽输送到中国东部。 500 hPa 异常高压抑制对流。地面风力减弱，有利于雾霾天气向东部地区集中。水平风垂直切变的减少削弱了天气扰动和大气垂直混合。近地表的异常逆温增加了地表空气的稳定性。 2013年1月的这些气象背景场有利于我国东部地区雾霾的维持和发展。对FHE日演化的诊断表明，对流层中下层的地面风速和水平风的垂直切变对雾霾具有动力作用。它们越大（越小），雾霾就越弱（越强）。热力学效应包括对流层中层和低层的层结不稳定性以及近地表的逆温和露点缺陷。层结不稳定性和逆温越大（越小），雾、霾越强（越弱）。同时，露点差越小（大），雾霾就越强（弱）。基于气象因素，建立多元线性回归模型。模型结果表明，动力和热力学对雾霾演化方差的影响几乎相同。气象因素对雾霾日演变方差的贡献度达到0.68，解释了2/3以上的方差。
In January 2013, a severe fog and haze event (FHE) of strong intensity, long duration, and extensive coverage occurred in eastern China. The present study investigates meteorological conditions for this FHE by diagnosing both its atmospheric background fields and daily evolution in January 2013. The results show that a weak East Asian winter monsoon existed in January 2013. Over eastern China, the anomalous southerly winds in the middle and lower troposphere are favorable for more water vapor transported to eastern China. An anomalous high at 500 hPa suppresses convection. The weakened surface winds are favorable for the fog and haze concentrating in eastern China. The reduction of the vertical shear of horizontal winds weakens the synoptic disturbances and vertical mixing of atmosphere. The anomalous inversion in near-surface increases the stability of surface air. All these meteorological background fields in January 2013 were conducive to the maintenance and development of fog and haze over eastern China. The diagnosis of the daily evolution of the FHE shows that the surface wind velocity and the vertical shear of horizontal winds in the middle and lower troposphere can exert dynamic effects on fog and haze. The larger (smaller) they are, the weaker (stronger) the fog and haze are. The thermodynamic effects include stratification instability in middle and lower troposphere and the inversion and dew-point deficit in near-surface. The larger (smaller) the stratification instability and the inversion are, the stronger (weaker) the fog and haze are. Meanwhile, the smaller (larger) the dewpoint deficit is, the stronger (weaker) the fog and haze are. Based on the meteorological factors, a multi-variate linear regression model is set up. The model results show that the dynamic and thermodynamic effects on the variance of the fog and haze evolution are almost the same. The contribution of the meteorological factors to the variance of the daily fog and haze evolution reaches 0.68, which explains more than 2/3 of the variance.