ITR/AP: Small-Scale Dynamical Interactions with Chemical Processes in the Terrestrial Upper Atmosphere

正在申请三年的资助期，以便PI可以扩展和修改他现有的模拟代码，以便放松以前仅因计算限制而实施的关键假设。他的数值模拟描述了小尺度重力波与次要物质的相互作用以及在中层顶区(90公里高度)的相关化学过程，是迄今为止最完整和最现实的。除了在次要物种数密度中引起大的、高度非线性的振荡之外，这些波还通过耗散效应驱动次要物种的大量向下输送。尽管该模型模拟了动力学和非线性化学之间依赖时间的相互作用，但该模型使用了线性(相对于非线性)动力学和数量非常有限(或不完全集)的化学活性次要物种。为了能够在合理的时间内在独立的个人计算机上运行代码，这些简化是必要的。然而，为了对相互作用有一个完整的了解，为了包括已知在这一大气层区域很重要的物理和化学过程，这两种理想化必须放松。这将大大增加计算负担，远远超出个人计算机的限制，需要多处理器计算机进行更快、更高效的计算。因此，PI提议购买一台相对便宜的“交钥匙”多处理器机器，以帮助他们在内部开发和测试提高模型真实感所需的代码，并随后将代码转移到国家大气研究中心更快的超级计算机上。拟议的工作属于国际交易日志提案的小班类别中的科学和工程应用部分，与地球科学局大气科学司的大气学方案关系最密切。

A three-year funding period is being requested so that the PI can expand and modify his existing simulation code in order to relax key assumptions that were previously implemented only because of computational constraints. His numerical simulations describing the interaction of small-scale gravity waves with minor species and related chemical processes in the mesopause region (90 km altitude) are the most complete and realistic to date. Quite apart from causing large, highly nonlinear oscillations in minor species number densities, the waves drive a large downward transport of minor species through the effects of dissipation. In spite of the fact that the model simulates time-dependent interactions between dynamics and nonlinear chemistry, the model uses linear (versus nonlinear) dynamics and a very limited number (or incomplete set) of chemically active minor species. These simplifications have been necessary in order to be able to run the code within a reasonable amount of time on stand-alone personal computers. However, to gain a complete understanding of the interactions and in order to include both physical and chemical processes that are known to be important in this region of the atmosphere, these two idealizations will have to be relaxed. This will increase the computational burden well beyond the limits of personal computers, requiring multiprocessor computers for faster, efficient computations. The PI is thus proposing to purchase a relatively inexpensive "turn-key" multiprocessor machine to assist them in the in-house development and testing of code required to increase the level of realism in their model, and subsequently transfer the code to faster super-computers at the National Center for Atmospheric Research. The proposed work falls into the Applications in Science and Engineering (AP) section of the small class category of ITR proposals, and is most closely related to the Aeronomy Program of the Atmospheric Science Division within the Directorate for Geosciences.