Inflow Boundary Layer of Atlantic Hurricanes

本研究的目的是表征海洋边界层流入飓风的能量含量的演变及其与飓风强度变化的关系。这项工作将与美国国家海洋和大气管理局飓风研究司目前计划的调查登陆飓风能量学的侦察任务合作完成。这项研究的关键新颖之处在于，美国国家海洋和大气管理局/夏威夷大学计划部署智能气球，作为拉格朗日实验策略的一部分。拉格朗日实验利用了NOAA WP-3D飞机上的新型高分辨率全球定位系统（GPS）投风探空仪、湍流通量传感器和多普勒雷达。由于流入中可能存在显著的横流变化，因此该计划包括获取流入层中空气包的热力学历史和轨迹的关键原位数据。气象和GPS位置数据将由一个经过验证的气球载仪器平台（智能气球）收集，该平台由NOAA的空气资源实验室、野外研究部开发。这些数据将通过卫星移动电话传输到国家飓风中心（NHC）和WP-3D飞机。智能气球具有很大的动态升力范围（海平面至6公里），由高强度球形外壳和内部加压气囊上的泵和释放阀提供。这种设计允许气球在边界层中保持在规定的高度运行限制内，尽管降水载荷和辐射加热和冷却对气球升力的影响。仪器和应答器包将被装入气球的外壳内，以保护它们免受环境危害。在每次实地试验开始时，两个智能气球将从飓风经过的250公里范围内的沿海地区部署。这一策略将允许NOAA WP-3D飞机在气球接近飓风眼壁时在气球附近进行一系列测量。气球放飞的地点和时间将根据NCEP对风暴轨迹的预测和夏威夷大学对空气包裹轨迹的预测来选择。受影响的美国海岸沿线的站点将作为释放点，调查来自大陆的气流的演变和影响，而岛屿站点（如波多黎各）可以作为释放点，调查仍然在公海上空的轨迹。这项研究将提高我们对飓风核心的热力学和角动量场之间的关系的理解。智能气球和飞机在实验过程中收集的实时数据，特别是风力数据，将提供给国家飓风中心和国家环境预测中心，以帮助准备飓风强度预测、观察和登陆前警报。

The purpose of this research is to characterize the evolution of the energy content of the marine boundary-layer inflow to hurricanes and its relationship with hurricane intensity changes. This effort will be accomplished in cooperation with reconnaissance missions currently planned by the NOAA Hurricane Research Division to investigate the energetics of landfalling hurricanes. The key novel feature of this research is the planned deployment of NOAA/U of Hawaii Smart Balloons as part of a Lagrangian experimental strategy. The Lagrangian experiment leverages the availability of new high-resolution Global Positioning System (GPS) dropwindsondes, turbulent flux sensors, and the Doppler radar on the NOAA WP-3D aircraft.Since there may be significant cross-stream variability in the inflow, the plan includes acquisition of critical in situ data on the thermodynamic history and trajectories of air parcels in the inflow layer. Meteorological and GPS position data will be collected by a proven balloon-borne instrument platform (Smart Balloon), developed at NOAA's Air Resources Lab, Field Research Division. The data will be transmitted via satellite cellular telephone to the National Hurricane Center (NHC) and the WP-3D aircraft. The Smart Balloon has a large dynamic lift range (sea level to 6 km), provided by a high strength spherical shell and a pump and release valve on an internal pressurized air bladder. This design allows the balloons to remain within prescribed altitude operating limits in the boundary layer despite precipitation loading and effects of radiative heating and cooling on balloon lift. The instrument and transponder package will be contained within the outer shell of the balloon to protect them from environmental hazards.At the outset of each field experiment, two smart balloons will be deployed from a coastal location within 250 km of a passing hurricane. This strategy will allow the NOAA WP-3D aircraft to make a series of measurements in the vicinity of the balloons as they approach the hurricane eyewall. Balloon release sites and times will be chosen based on storm-track predictions from NCEP and forecasts of air-parcel trajectories made at the University of Hawaii. Sites along the affected US coast will serve as release points to investigate the evolution and impact of air streams of continental origin, while island sites (e.g., Puerto Rico) can serve as release points to investigate trajectories that remain over the open ocean. This research will improve our understanding of how the thermodynamics and angular momentum fields in the core of hurricanes are related. Real-time data, especially wind data, collected by the Smart Balloons and aircraft during the experiment will be made available to the National Hurricane Center and the National Center for Environmental Prediction to aid in preparation of hurricane intensity forecasts, watches, and warnings prior to landfall.