Collaborative Research: Barrier Jets in the Gulf of Alaska - Causes, Impacts, and Interactions with Other Phenomena

具有突出地形的海岸线附近的中尺度大气流动对在海岸环境中生活和工作的人们有着巨大的影响。 然而，这类局部风系统仍然是天气预报中具有挑战性和重要性的问题。 最常见的地形引起的海岸流之一，障碍射流，创造特别危险的天气条件，特别是在阿拉斯加东南部和太平洋西北部。 由此产生的强风对生命、财产和经济活动构成威胁。 解决这些社会问题需要研究，以提高对沿海屏障射流的动态及其形成所需的大规模天气条件的理解。卫星遥感技术的最新进展为进一步了解障壁喷流提供了机会。 例如，合成孔径雷达（SAR）提供了表面风速的详细测量，分辨率为数百米，范围为数百公里。 此外，通过SAR可以观测到距离海岸线1公里以内的风速场。 这些合成孔径雷达速度观测结果可与其他观测结果和模型输出相结合，以提供整个沿海地区的高分辨率风矢量图。 这些SAR衍生的风图从几千个案例在过去5年中，存档在约翰霍普金斯大学应用物理实验室，代表了一个独特的资源，为发展的障碍射流沿着阿拉斯加海岸的更好的理解。 这个档案包含了阿拉斯加湾上100个障碍射流的案例。 在该项目中，主要调查员将利用这一档案，沿着其他图像、现场观测和数值模拟，以更好地了解沿着北美西海岸的屏障射流的动态及其形成所需的大尺度天气条件，从而为这一危险现象的业务预报提供基础。将研究与障碍射流相关的流动和局部海洋环流之间的相互作用。 障碍急流气候学将用于绘制与阿拉斯加湾障碍急流相关的季节平均风应力异常。 这些风应力异常图将用于确定与障碍射流相关的平均埃克曼泵送以及由此产生的上层海洋响应。 这些结果可以与系泊浮标的现场观测结果进行核对，并用于研究屏障射流对海洋生态系统的影响。 这些发现将为渔业以及海洋生物学和物理海洋学研究界提供重要信息。

The mesoscale atmospheric flow near coastlines with prominent terrain has a tremendous impact on those who live and work in the coastal environment. Yet this class of localized wind systems remains a challenging and important problem in weather prediction. One of the most common terrain-induced coastal flows, the barrier jet, creates especially dangerous weather conditions, particularly in southeast Alaska and the Pacific Northwest. The resulting severe winds pose a threat to life, property, and economic activities. Addressing these societal issues requires research to improve understanding of the dynamics of coastal barrier jets and the larger-scale weather conditions required for their formation. Recent advances in satellite remote sensing technology provide an opportunity to further understanding of barrier jets. For example, synthetic aperture radar (SAR) provides detailed measurements of the surface wind speed with resolutions of hundreds of meters over regions several hundred kilometers on a side. Moreover, with SAR the wind speed field can be observed to within 1 km of the coastline. These SAR speed observations can be combined with other observations and model output to provide high-resolution wind vector maps throughout the coastal zone. These SAR-derived wind maps from several thousand cases over the past 5 years, archived at the Johns Hopkins University Applied Physics Laboratory, represent a unique resource for the development of improved understanding of barrier jets along the Alaskan coast. This archive contains on the order of 100 cases of barrier jet flows over the Gulf of Alaska. In this project, the Principal Investigators will exploit this archive, along with additional imagery, in situ observations and numerical simulations to gain a greater understanding of the dynamics of barrier jets along the western coast of North America and of the larger-scale weather conditions required for their formation, thereby providing the basis for operational forecasting of this hazardous phenomenon.Additionally, the interactions between the flow associated with barrier jets and local ocean circulations will be investigated. The barrier jet climatology will be used to map the seasonal mean wind stress anomalies associated with barrier jets in the Gulf of Alaska. These wind stress anomaly maps will be used to determine the mean Ekman pumping associated with barrier jets and the resulting upper ocean response. These results well be checked against in situ observations from moored buoys and used to examine the impact of barrier jets on the marine ecosystem. These findings will provide important information to the fisheries industry as well as the marine biology and physical oceanography research communities.