蒙古高原风蚀颗粒物空间过程数值模拟及预报

基于WRF-IWEMS耦合模型对2016年3月1~9日发生在蒙古高原的强沙尘天气过程进行数值模拟，着重模拟了尘源、粉尘传播路径以及粉尘扩散过程中浓度变化和影响范围，并采用卫星影像、站点监测数据与模型结果进行对比分析。结果表明：此次风沙天气过程的尘源分布在新疆哈密地区、阿拉善高原、中蒙边境戈壁地区以及浑善达克沙地部分地区，粉尘自源区分别沿河西走廊、贺兰山区、张家口等地扩散至华北和京津地区。蒙古高原土壤风蚀可使华北地区来自自然源的大气颗粒物PM₁₀、PM_2.5浓度分别达到1 000 μg·m^-3、200 μg·m^-3以上，还可使华北地区大气颗粒物浓度高于200 μg·m^-3的天气持续48 h以上。

Numerical simulation and prediction spatial process of wind erosion particles in Mongolian Plateau

The WRF (Weather Research and Forecasting) is widely used in mesoscale weather simulation and prediction as a new generation mesoscale atmospheric model.IWEMS (Integrated Wind-Erosion Modeling System) is an integrated wind erosion model,including regional atmospheric model,land surface model,dust model and geographic information system.In this study,the numerical simulation of the strong dust storms event in the Mongolian Plateau from March 1 to March 9,2016 was conducted based on the WRF-IWEMS coupling model,with the focus on the dust source,dust transport path and the dust concentration change and influence scope during its diffusion process.The modeling results were compared with MODIS aerosol products and the monitoring data by the monitoring stations.The results indicated that the dust source of this dust storm event included the Hami region of Xinjiang,the Alxa Plateau,the Gobi region of the Sino-Mongolian border and parts of the Hunshadake sandy land.The dust was spread to North China including the region of Beijing and Tianjin along the Hexi Corridor,Helan Mountains and Zhangjiakou.The high concentration of dust covered almost Northwest China,and the low concentration of dust was spread to an even wider area from the beginning of the wind erosion process to its end.As the natural source for the atmospheric particulates,the soil wind erosion in Mongolian plateau can make PM₁₀ and PM_2.5 concentration in North China reach 1 000 μg·m^-3 and 200 μg·m^-3 respectively,and the time when the atmospheric particulate matter being above 200 μg·m^-3 more than 48 hours.The area of the dust event,the change on the strength and concentration of the dust were all in good agreement with the MODIS aerosol products in the simulation results.The WRF-IWEMS coupling model can simulate the spatial distribution characteristics and changes of PM_2.5 and PM₁₀ during the dust storm process in Mongolian Plateau,and also simulate the dust source distribution and migration space of the natural source dust which can provide data support for air pollution control in North China.