HF radar observation of nearshore winds
HF radar observation of nearshore winds
复制标题
DOI：
10.1049/sbra537e_ch8
复制
发表时间：
2021-12
期刊：
影响因子：
--
通讯作者：
B. Emery;A. Kirincich
中科院分区：
文献类型：
--
作者：
B. Emery;A. Kirincich
在埃克曼于1905年对风应力对海洋的影响进行了数学描述之后，测量风场本身已经成为了解洋流运动的关键部分。在沿海地区尤其如此，风和波浪与沿海边界相互作用，在空间和时间上驱动复杂的水流。除了了解和预测沿海流动，观测近海岸表面风是满足科学（如循环，混合，生物生产力，幼虫运输）和社会需求（如航运，风力发电）的基础。近海岸风观测，无论是在现场还是远程，通常具有高的时间分辨率，或高的空间分辨率，但不是两者兼而有之。基于浮标的观测，例如通过国家数据浮标中心（NDBC）获得的观测，提供了来自大多数沿海地区的风产品的时间序列，但缺乏空间相关的分辨率来观测许多（如果不是大多数）关键的小尺度环流过程。最近的发展已将卫星散射计的能力提高到距离海岸10-15公里以内（例如，[2，3]），同样，合成孔径雷达（SAR）在距离海岸1-3 km的范围内实现了亚km分辨率（0.5-1 km），RMS误差为1.4-1.8 m s−1 [4，5]。虽然计划中的未来任务，如波浪和海流使命（WACM）[6]将进一步推进这些技术，并提供高空间分辨率的风图，但基于卫星的观测采样周期为12小时或更长，限制了其科学用途。相比之下，陆基高频雷达系统通常在所有天气条件下对沿海海洋的表面流进行高空间和高时间分辨率观测。雷达系统观察到的基本信号是由于存在相对较短的海浪，这些海浪对风速和风向的变化反应迅速。在近海岸，来自这些系统的风观测将填补卫星观测与系泊观测之间的一个重要空白，卫星观测在靠近陆地时遇到困难，而系泊观测在空间上密集部署成本过高。可能的空间和时间覆盖范围，时间尺度为10分钟，空间尺度为2-6公里，与推进目前对沿海海洋环流的理解和建模所需的最可能的分辨率相匹配[7，8，9]。
Following Ekman’s 1905 mathematical description of the influence of wind stress on the ocean, measurement of the wind field itself has been a critical part of any effort to understand the movement of ocean currents. This is particularly true in the coastal zone, where winds and waves interact with the coastal boundary to drive spatially and temporally complex currents. In addition to understanding and predicting coastal flows, observations of near shore surface winds are fundamental to fulfilling both scientific (e.g. circulation, mixing, biological productivity, larval transport) and societal needs (e.g. shipping, wind power). Near shore wind observations, either in situ or remote, typically have high temporal resolution, or high spatial resolution, but not both. Buoy-based observations, such as those accessible via the National Data Buoy Center (NDBC), provide time series of wind products from most coastal areas but lack the spatially relevant resolution for observing many – if not most – of the critical small scale circulation processes. Recent developments have improved satellite scatterometer capabilities to within 10-15 km from shore (e.g.[2, 3]), and similarly, Synthetic Aperture Radar (SAR) achieves sub-km resolution (0.5-1 km) up to 1-3 km from shore with RMS errors of 1.4-1.8 m s−1 [4, 5]. While planned future missions such as the Waves and Currents Mission (WACM) [6] would further advance these techniques and provide maps of winds with high spatial resolution, satellite-based observations sample at periods of 12 hours or greater, limiting their scientific utility. In contrast, land-based HF radar systems routinely provide both high spatial and high temporal resolution observations of surface currents in the coastal ocean in all weather conditions. The fundamental signal observed by the radar system results from the presence of relatively short ocean waves that respond quickly to changes in wind speed and direction. In the near shore, wind observations from these systems would fill an important niche between satellite observations, which encounter difficulties close to land masses, and moored observations, for which spatially dense deployments are cost prohibitive. The spatial and temporal coverage possible, with time scales of 10s of minutes and spatial scales of 2-6 kilometers, matches the most likely resolution needed to advance the present understand and modelling of coastal ocean circulation [7, 8, 9].