Microfronts 1995 and Cases 1999: Boundary Layer Influences on Fronts and Inertial Oscillations

发生在地球边界层（与地面接触的相对较浅的一层）的过程通常对大气锋面有重大影响，并且是波浪运动和大气振荡的来源。1995年在堪萨斯州进行的实地调查（MICROFRONTS）提供的数据包括高频热线风速计的风和安装在10米塔阵列上的声波风速计的风和温度。手术时出现了三个额部通道。将继续分析这些数据和其他低频观测数据，以确定表征锋面的动能耗散率和湍流特征。这些运动发生在数值大气模式的亚网格时空尺度上。所有或大多数模型要么没有规定湍流耗散贡献，要么处理得不好。目前的目的是提供必要的数据分析和理论理解，这是最终参数化与锋面相关的湍流耗散所必需的。锋面的通过和日落附近边界层高度的相对突变似乎是内部重力波和惯性振荡的起源。四年来，来自美国国家海洋和大气管理局风廓线网络的数据，以及来自阿贡国家实验室在堪萨斯州维护的三台廓线仪的数据，将通过旋转频谱技术进行分析。目的是提取大气惯性振荡的特性，并建立边界层模型，以确定锋面和边界层深度变化在其发生中的相对重要性。这些振荡对锋面动力学的作用将继续通过使用锋生模型进行研究。这些振荡的来源和特征也被认为对大气色散的远程模拟很重要。为此目的正在进行的模型开发对于预测城市空气质量具有相当重要的意义。目前的数据库将通过参加1999年10月在堪萨斯州南部开展的一个实地项目（1999年合作大气-地表交换研究）而得到扩展。这些数据将与正在进行的模型开发一起使用，以改进和验证模型预测。预计观测阵列将适合于获取隔离边界层源所需的数据，用于惯性振荡和内部重力波。

Processes that occur in the Earth's boundary layer, the relatively shallow layer in contact with the ground, often have a significant effect on atmospheric fronts and are a source of wave motions and atmospheric oscillations. Data available from a previous field investigation in Kansas in 1995 (MICROFRONTS) consists of high frequency hot-wire anemometer winds and both wind and temperature from sonic anemometers mounted on 10 meter tower arrays. Three frontal passages occurred when the instruments were operative. These data, and other lower frequency observations, will continue to be analyzed to determine the kinetic energy dissipation rate and turbulence characteristics that characterize fronts. These motions occur on subgrid spatial and temporal scales of numerical atmospheric models. The turbulent dissipative contributions are either not prescribed or handled ineffectively by all or most models. The present aim is to provide the necessary data analysis and theoretical understanding that is required to ultimately parameterize turbulent dissipation associated with fronts.The passage of fronts and the relatively abrupt change in the height of the boundary layer near sunset appear to be sources for the initiation of internal gravity waves and inertial oscillations. Four years of data from the National Oceanic and Atmospheric Administration wind profiler network, and from three profilers maintained in Kansas by the Argonne National Laboratory, will be analyzed by the rotary spectrum technique. The purpose is to extract properties of atmospheric inertial oscillations, and to develop boundary layer models that will establish the relative importance of fronts and boundary layer depth changes in their occurrence. The role of these oscillations on the dynamics of fronts will continue to be investigated by use of frontogenesis models. The source and characteristics of these oscillations has also been recognized as important for long-range modeling of atmospheric dispersion. Ongoing model development for this purpose is of considerable importance in the prediction of urban air quality.The current data bases will be expanded by participation in a field program to be carried out in southern Kansas in October 1999 (Cooperative Atmosphere-Surface Exchange Study -- 1999). These data will be used with ongoing model developments to both improve and to verify model predictions. The observational arrays are expected to be suitable to acquire data that is required to isolate boundary layer sources for both inertial oscillations and for internal gravity waves.