中文摘要：

采用大涡模拟方法，利用平坦地面模型和带楔形结构的粗糙地面模型研究近地面空间风场特征。结果表明，在时变来流条件下，平坦地面模型和粗糙地面模型均在阵风峰期产生下沉气流，在阵风谷期产生上升气流；垂直气流大小与下垫面粗糙度和水平来流风速变化幅度有关。大气边界层内风场的风速大小和方向总是随时间变化的，与稳定来流假设相比，随时间变化的来流条件下边界层的流动更有利于边界层内物质和能量的输运。

英文摘要：

In large eddy simulations （ LES） , a flat ground model and rough wedge ground models with different wedge heights were adopted to investigate near-surface wind field characteristics under condition of time-varying upstream inflows. In both flat ground model and rough wedge ground models, simulated results show that there is downdraft in peak period of gusty wind and updraft in valley period, respectively. Intensity of downdraft/updraft flows are related to ground roughness in upwind areas and amplitude of inflows. It follows that wind velocity and direction in atmospheric boundary layer always change over time in time-varying upstream inflows, which enhances transportation of mass and energy in actual atmospheric boundary layer.