Orographic Forcing of the Coastal Atmospheric Boundary Layer

9526138座罗杰斯海岸山脉形成了风场的屏障，这可能会影响当地气流的下游和上游演变。海岸带产生的高或低气压的局部区域可能会被困住，并沿着海岸线传播。精力旺盛、持续两到六天的骚乱尤其令人感兴趣。这些特征可能导致沿海地区当地天气发生重大变化，例如，用云和雾取代晴朗的天空，并导致风场增强和逆转。这些系统被很好地记录下来，但没有研究描述它们的动力结构、起源、与平均边界层的相互作用以及伴随这些事件的云盖层的发展。与海岸障碍物相关的气流的加速导致沿海海洋的强风强迫和低层气流速度的快速变化。这些地形强迫流动对海洋和大气之间的热量、水分、动量和痕量成分的交换产生了重大影响。由于这些水流受到地形的限制，它们往往是静止的和持续的，持续地影响着海岸线的特定区域。虽然这些特征的基本结构是已知的，但它们只被记录在少数情况下，没有专门针对确定这些特征的动力学及其与热环流的相互作用的系统研究，热环流也是夏季加州海岸带的一个重要的中尺度特征。这项工作将侧重于利用飞机和地面测量对边界层的沿海岸和跨海岸结构进行现场测量。飞机仪器将提供沿海大气平均和湍流结构的直接测量、海洋边界层变形的一致激光雷达测量以及沿海云和气溶胶的现场云微物理测量。一个重要的结果将是能够分辨控制加州海岸部分地区中尺度风场变化的时间和空间尺度，这可能对复杂地形中的中尺度预报和数值模拟产生重大影响。***

9526138 Rogers Coastal mountains form a barrier to the wind field that may affect both the downstream and upstream evolution of the local air flow. Local regions of high or low pressure generated by the coastal zone can become trapped and propagate along the coastline. Energetic, disturbances that exist for between two and six days are of particular interest. These features can cause significant changes in the local weather in the coastal zone, for example, replacing clear skies with clouds and fog, and causing intensification and reversals of the wind field. These systems are well documented, but no studies have characterized their dynamical structure, origin, interaction with the mean boundary layer and the development of the cloud-capped layer that accompanies these events. Accelerations of the flow associated with coastal barriers give rise to strong wind forcing of the coastal ocean and rapid variations in the speed of the low level air flow. These orographically-forced flows have a significant effect on the exchange of heat, moisture, momentum and trace constituents between the ocean and the atmosphere. Since these flows are constrained by the topography, they are often stationary and persistent, consistently affecting a particular area of the coastline. While the basic structure of these features is known, they have been documented on only a few occasions and no systematic study has been directed specifically to identifying the dynamics of these features and their interactions with the thermal circulation that is also a significant mesoscale feature of the summer-time California coastal zone. This work will focus on in situ measurements of the along shore and across shore structure of the boundary layer using aircraft and surface based measurements. Aircraft instruments will provide direct measurements of the mean and turbulent structure of the coastal atmosphere with coincident lidar measurements of the deformation of the marine bounda ry layer inversion and in situ cloud microphysical measurements of coastal clouds and aerosols. An important result will be the ability to resolve the temporal and spatial scales that dominate the variability of the mesoscale wind field along parts of the California coast, which may have a significant impact of mesoscale forecasting and numerical modeling in complex terrain. ***