DEEPWAVE: Spatial and Fourier Ray Modeling of Mountain Waves

该项目将是国际DEEPWAVE运动的一部分，该运动将设法了解从地面到100公里高度的地形和其他来源产生和传播大气重力波的情况，并将使用机载和地面仪器以及建模。它将于2014年6月/7月在新西兰、塔斯马尼亚和周围南大洋附近的该地区举行。该项目将为DeEPWAVE提供射线跟踪分析和预报，重点是山波。将使用两个互补的光线公式：傅立叶空间光线追踪和空间光线追踪。傅里叶空间射线追踪主要适用于波幅往往最高、空间光线追踪往往不能满足缓慢变化要求的山脉正上方地区。傅里叶空间射线追踪也可以耦合到中尺度模式模拟，以改善傅里叶空间射线的初始条件。空间射线追踪主要用于山波在极地夜间急流中的传播，通过水平和垂直变化的风切变对三维几何传播进行了新的处理。这项工作将涉及对几何传播的新分析，这一过程在几乎所有重力波的光线追踪研究中都被忽略了，这一过程在DEEPWAVE地区可能是重要的。将首次检查几何扩展的方向性和各向异性等方面，并可能为改进重力波参数提供线索。DEEPWAVE项目将促进国际科学合作。了解重力波在中高层大气中的传播和分解关系到许多战略和社会问题，包括高空飞行器的安全、天气和气候模型的准确性以及预报影响卫星通信的某些空间天气现象的能力。

This project will be part of the international DEEPWAVE campaign which will seek to understand the generation and propagation of atmospheric gravity waves from orographic and other sources from ground-level up to 100 km altitude, and will use airborne and ground-based instrumentation as well as modeling. It will take place in June/July 2014 in the region over New Zealand, Tasmania and the surrounding Southern Ocean. This project will provide ray-tracing analysis and forecasts for DEEPWAVE, with an emphasis on mountain waves. Two complementary ray formulations will be used: Fourier space ray-tracing and spatial ray-tracing. The Fourier-space ray-tracing is mainly for the region directly above mountains, where wave amplitudes tend to be highest and where spatial ray-tracing often fails to satisfy slowly varying requirements. The Fourier-space ray-tracing can also be coupled to a mesoscale model simulation to improve initial conditions for the Fourier-space rays. The spatial ray-tracing is mainly for mountain-wave propagation through the Polar Night Jet, with a new treatment of the three-dimensional geometrical spreading by horizontally and vertically varying wind shear.The work will involve a new analysis of geometrical spreading, a process that is omitted from almost all ray-tracing studies of gravity waves and that is likely to be important in the DEEPWAVE region. Aspects such as the directionality and anisotropy of the geometrical spreading will be examined for the first time and may provide clues for improved gravity wave parameterizations. The DEEPWAVE project will promote international scientific collaboration. Understanding gravity wave propagation and breakdown in the middle and upper atmosphere is related to a number of strategic and societal issues, including the safety of high altitude aircraft, the accuracy of weather and climate models, and the ability to forecast certain space weather phenomena that affect satellite communication.