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何晖, 郭学良, 李宏宇, 等. 人工消除冷雾的个例模拟分析[J]. 大气科学, 2011, 35(2): 272-286. DOI: 10.3878/j.issn.1006-9895.2011.02.07
引用本文: 何晖, 郭学良, 李宏宇, 等. 人工消除冷雾的个例模拟分析[J]. 大气科学, 2011, 35(2): 272-286. DOI: 10.3878/j.issn.1006-9895.2011.02.07
He Hui, Guo Xueliang, Li Hongyu, et al. Numerical Simulation of the Cold Fog Dissipation[J]. Chinese Journal of Atmospheric Sciences, 2011, 35(2): 272-286. DOI: 10.3878/j.issn.1006-9895.2011.02.07
Citation: He Hui, Guo Xueliang, Li Hongyu, et al. Numerical Simulation of the Cold Fog Dissipation[J]. Chinese Journal of Atmospheric Sciences, 2011, 35(2): 272-286. DOI: 10.3878/j.issn.1006-9895.2011.02.07

人工消除冷雾的个例模拟分析

Numerical Simulation of the Cold Fog Dissipation

  • 摘要: 本文在中尺度数值模式MM5的Reisner2方案中引入了液氮粒子与云相互作用的过程, 在中尺度模式MM5中实现了催化功能。利用加入催化方案的中尺度模式针对2007年12月26日北京地区的一次冷雾天气过程进行了消雾的数值模拟研究, 探讨了消雾的效果和机理, 并针对催化剂的播撒量和播撒位置进行了两组敏感性试验。结果表明:在此次模拟雾过程中, 在目标区上风方1~2 km以5 g/s的播撒速率播撒10 min, 催化作业开始9 min后, 目标区开始显现作业效果, 最好的效果出现在作业后24 min, 作业效果可以维持25 min左右。消雾机理主要为播撒后人工冰晶通过凝华增长消耗了大量的水汽, 导致了水汽通过凝结过程形成雾滴的减少, 同时上游作业导致雾滴向下游目标区平流的减少。本例中, 以15 g/s的速率播撒作业和在目标区上风方5~6 km的地点作业对能见度的改善最为显著。

     

    Abstract: Based on the dynamic frame of mesoscale model MM5 and Reisner2 explicit cloud scheme, a LN (liquid nitrogen) -seeding scheme was developed and used to simulate the cold fog dissipation for the cold fog event on 26 December 2007 in Beijing area. The seeding effect and the physical mechanism were studied. Furthermore, two sensitive experiments were performed to study the seeding effect under different seeding distances and seeding amounts. The results indicate that when the seeding operation lasts 10 min at seeding rate of 5g/s with distance being about 1-2 km on the upwind side of the target area, the seeding effect in the target area begins to appear at 9 min after seeding operation and the best effect appears at 24 min after seeding operation, the seeding effect can last about 20 min. The microphysical mechanism of the cold fog dissipation is because of the depletion of the water vapor due to the ice sublimation growth induced by seeding, which leads to the decrease of the water vapor condensation into fog droplets, meanwhile the decrease of the fog advection from the upstream region after seeding operation also contributes to the fog dissipation. In this case, seeding operation at seeding rate of 15 g/s with distance being about 5-6 km on the upwind side of the target area can make the target area have the most significant improvement in the visibility.

     

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