内蒙古一次沙尘过程的数值模拟

利用WRF-chem模式耦合Shao04起沙参数化方案，研究了2015年内蒙古春季一次冷涡沙尘过程。对比分析模式模拟结果和Micaps、CLIPSO、PM₁₀观测资料后发现，WRF-chem可以较好地刻画沙尘的水平和垂直输送。此次沙源地主要分布在蒙古国南部、内蒙古中部偏北区域和浑善达克沙地。蒙古国南部和内蒙古中部偏北区域最大起沙量分别为77.4 g·m^-2和112.7 g·m^-2，最大干沉降分别为253.2 μg·m^-2·s^-1和427.2 μg·m^-2·s^-1，内蒙古中部偏北区域的沙尘柱总量（87.3 g·m^-2）大于蒙古国南部（41.3 g·m^-2）。浑善达克沙地土壤干燥，所以沙尘排放量（215.6 g·m^-2）、柱总量（132.7 g·m^-2）、沉降速率（809.3 μg·m^-2·s^-1）均较高。沙尘在锋前暖湿气流的抬升作用下，可以实现上对流层-下平流层之间的输送，高层的沙尘虽然浓度较低，却可以输送更远。沙尘气溶胶夜间增加大气层顶向上的长波辐射，同时加热大气，增加边界层高度。

Numerical simulation of a dust process in Inner Mongolia of China

Based on the WRF-chem model coupled Shao04 parameterization scheme, a typical cold vortex dust process in Inner Mongolia in spring of 2015 was studied. The WRF-chem model can better describe the horizontal and vertical transmission of dust comparing model simulation with Micaps, CALIPSO, PM₁₀ observation data. The sand source is mainly distributed in the south of Mongolia, the north of Inner Mongolia and Otindag Sandy Land. The largest dust emission are 77.4 g·m^-2 and 112.7 g·m^-2 in the south of Mongolia and the north of Inner Mongolia. The dry sedimentation rate of the north of Inner Mongolia and the south of Mongolia is 427.2 μg·m^-2·s^-1 and 253.2 μg·m^-2·s^-1, respectively. The dust load in the north of Inner Mongolia(87.3 g·m^-2) is larger than in the south of Mongolia (41.3 g·m^-2). Because of the dryer soil moisture in Otindag Sandy Land, the dust emission (215.6 g·m^-2), dust load (132.7 g·m^-2) and sedimentation rate (809.3 μg·m^-2·s^-1) are larger than in the south of Mongolia and the north of Inner Mongolia. Under the action of the warm air ascending motion ahead of the front, the dust aerosol can be transported between the upper troposphere and lower stratosphere. Although the high-level dust may have a low concentration, it can be transmitted farther distances. Dust aerosols increase upward longwave radiation at TOA (the top of atmosphere) at night, while heating the atmosphere and increasing the boundary layer height.