Numerical Simulation of Gravity Wave Propagation, Instability Dynamics, and Spectral Evolution in the Mesosphere and Lower Thermosphere (MLT)

研究人员将进行一项全面的模拟工作，旨在了解重力波的传播、光谱能量传输、平均流相互作用以及中间层和低热层(MLT)中的波和湍流传输。该方法包括两种建模方法：一种是高度并行的不可压缩直接模拟代码，另一种是新测试的谱元素代码。要讨论的具体问题包括：(1)不稳定对限制重力波振幅和通量的作用；(2)波-波相互作用和局部不稳定过程在控制波幅方面的竞争；(3)波叠加在控制相互作用过程中的作用；(4)热和动量的混合和湍流传输；(5)重力波动力学对MLT大尺度波场的影响。这些结果将有助于量化重要的重力波动力学，这些动力学在很大程度上仍然未知，并对模拟重力波效应具有重要意义。这些结果将应用于气候变化、对流层和空间天气、太阳对大气的强迫以及对流层光学湍流。

The investigators will conduct a comprehensive modeling effort aimed at understanding gravity wave propagation, spectral energy transfers, mean-flow interactions, and wave and turbulent transports in the mesosphere and lower thermosphere (MLT). The approach involves two modeling methodologies: a highly-parallel incompressible direct simulation code and a newly-tested spectral-element code. Specific topics to be addressed include (1) the role of instabilities in limiting gravity wave amplitudes and fluxes, (2) the competition between wave-wave interactions and local instability processes in controlling wave amplitudes, (3) the role of wave superposition in controlling interaction processes, (4) the mixing and turbulent transports of heat and momentum, and (5) the effects of gravity wave dynamics on the large-scale wave fields in the MLT. The results will help quantify important gravity wave dynamics that remain largely unknown and have significant implications for modeling gravity wave effects. These results will have application to climate change, tropospheric and space weather, solar forcing of the atmosphere, and tropospheric optical turbulence.