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

地形突出的海岸线附近的中尺度大气流动对在沿海环境中生活和工作的人们有着巨大的影响。然而，这类局部风系统在天气预报中仍然是一个具有挑战性和重要的问题。最常见的地形引起的海岸气流之一，屏障射流，造成了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进行研究，以提高对海岸屏障射流动力学的理解，以及它们形成所需的更大规模天气条件。卫星遥感技术的最新进展为进一步了解障壁射流提供了机会。例如，合成孔径雷达（SAR）提供了地表风速的详细测量数据，其分辨率为数百米，覆盖了一侧数百公里的区域。此外，利用SAR可以观测到海岸线1公里范围内的风速场。这些SAR速度观测可以与其他观测和模式输出相结合，以提供整个沿海地区的高分辨率风矢量图。这些由sar导出的风图来自过去5年里数千个案例，保存在约翰霍普金斯大学应用物理实验室，为改善对阿拉斯加海岸障壁射流的理解提供了独特的资源。这个档案包含了大约100例阿拉斯加湾上空的屏障射流。在这个项目中，首席研究人员将利用这些档案，以及额外的图像、现场观测和数值模拟，以更深入地了解北美西海岸屏障射流的动力学，以及形成屏障射流所需的更大规模天气条件，从而为这种危险现象的业务预测提供基础。此外，还将研究与屏障射流相关的气流与局部海洋环流之间的相互作用。障壁急流气候学将用于绘制阿拉斯加湾与障壁急流相关的季节性平均风应力异常。这些风应力异常图将用于确定与屏障射流相关的平均埃克曼泵和由此产生的上层海洋响应。这些结果很好地与系泊浮标的现场观测结果进行核对，并用于检查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.