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

目前正在申请为期三年的资助期，以便PI可以扩展和修改他现有的模拟代码，以放宽以前仅因计算限制而实现的关键假设。他的数值模拟描述了中顶区域（海拔90公里）小尺度重力波与次要物质的相互作用以及相关的化学过程，是迄今为止最完整和最真实的。除了在小物种数密度中引起大的、高度非线性的振荡外，这些波还通过耗散的作用驱动小物种的大量向下输运。尽管该模型模拟的是动力学和非线性化学之间随时间变化的相互作用，但该模型使用的是线性（相对于非线性）动力学和数量非常有限（或不完全集合）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，为了完全了解相互作用，并为了包括已知在大气的这一区域中重要的物理和化学过程，这两种理想化情况必须放宽。这将增加计算负担，远远超出个人计算机的极限，需要多处理器计算机来进行更快、更有效的计算。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所需的代码，以提高模型的真实感水平，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ITR提案小班类别的科学与工程应用（AP）部分，与地球科学理事会大气科学部的航空计划关系最为密切。

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.