CEDAR: Numerical Investigation of Observed Multiscale Dynamics in the Middle Atmosphere

这是一个为期3年的建模工作，作为大气区域耦合、能量学和动力学项目的一部分。大气重力波被认为在大气层之间的能量和动量传输中起着至关重要的作用。这种传输是通过这些波在背景大气中的垂直传播而实现的，而这些波的消散则是通过不稳定性（对流和切变不稳定性）的增长而发生的。本项目利用两种先进的数值模拟方法研究了中低层热层（MLT）区域的重力波和不稳定过程。以往的模拟都是在理想环境和小周期域下进行的。在这里，模拟将扩展到深域研究，这将检查这些波动和不稳定过程在更现实的流动中受到详细观察的启发。重力波是MLT动力学的重要强迫源，其影响强烈地影响着大气环流和气候模式。此外，数值天气预报模式虽然以对流层为重点，但已被证明，当高层大气动力学模型更精确时，它能做出更好的预测。具体来说，通过这一努力，提高了对重力波在现实流动中何时/何处变得不稳定的理解，这是在全球尺度模型中改进重力波参数化的重要一步。

This is a 3-year modeling effort to be undertaken as part of the Coupling, Energetics and Dynamics of Atmospheric Regions program. Atmospheric gravity waves are believed to play a vital role in the transport of energy and momentum between atmospheric layers. This transport is enabled by the propagation of these waves vertically through the background atmosphere and dissipation of these occurs via the growth of instabilities (both convective and shear instabilities). This project utilizes two advanced numerical simulations to investigate gravity wave and instability processes in the Mesosphere-Lower Thermosphere (MLT) region. Previous simulations have been performed in idealized environments and small periodic domains. Here, the simulations will be extended to deep domain studies, which will examine these wave and instability processes in more realistic flows inspired by detailed observations.Gravity waves are a significant forcing source on MLT dynamics and their effects strongly impact general circulation and climate models. In addition, numerical weather prediction models, despite their tropospheric focus, have been shown to make better predictions when the upper-atmospheric dynamics are more accurately modeled. Specifically, improved understanding of when / where gravity waves become unstable in realistic flows that would result from this effort is a vital step towards improving parametrization of these waves in global-scale models.