Multi-Scale Dynamics of Gravity Waves MS-GWaves (Coordination proposal)

只有以正确的理由对当前气候进行正确的建模，才能获得对气候预测的信心。目前，关于布鲁尔-多布森环流的预测增强、平流层与对流层的动力向下耦合、臭氧的超恢复等动力学特征存在争议。在这种情况下，一个特别大的不确定性来源是内部重力波(GWS)，它不能用当前的化学-气候模型来解决，而是用大大简化的参数化来表示。研究单位(RU)将以物理和数学上一致的方式制定GW激发、传播和耗散的显式模型。这些将通过过程解析的数值建模和测量进行测试。将特别关注重力波与湍流、与平衡流的多尺度相互作用，以及未分辨的小尺度重力波与大尺度、可分辨的重力波相互作用。有待开发的模型将导致从GWS的来源到其消散的统一的参数化。GW参数化和全球GW允许和局地GW分辨率模式将被用于量化和减少GW对大气环流、大气中的大尺度动力过程和气候变化的影响的不确定性。这项工作将基于数学、理论、高分辨率数值模拟和对波浪过程本身及其在全球范围内的影响的测量的密切跨学科互动。之所以采用这种方法组合，是因为只有测量才能与现实直接联系，只有理论才能理解，而且只有高分辨率的建模才能提供详细的诊断。这样一个全面的计划远远超出了单个研究机构或一些双边合作的可能性，但需要一个RU，各个机构加入他们的实验、计算和理论能力。从RU获得的长期收益将是：-增强和深化对大气中GW的空间、时间和光谱分布的概述。-显著提高对引起和控制相应GW动态的过程的理解。-在此基础上，增加GW作为次网格尺度现象的参数化的稳健性和完整性，解决源过程、GW传播、GW平均流相互作用和GW耗散。-因此，GW参数化在异常条件下的性能更可靠，例如气候变化。

Confidence in climate prediction can only be gained if the present climate is modeled correctly for the correct reasons. Currently, there is a debate on dynamical features such as the predicted enhancement of the Brewer-Dobson circulation, the dynamical downward coupling of the stratosphere on the troposphere, and ozone super-recovery. A particularly large source of uncertainty in this context are internal gravity waves (GWs), which cannot be resolved by current chemistry-climate models and are represented by largely oversimplified parameterizations instead. The research unit (RU) will formulate explicit models of GW excitation, propagation, and dissipation in a physically and mathematically consistent way. These will be tested via process-resolving numerical modeling and measurements. Special attention will be given to multi-scale interactions of gravity waves with turbulence, with the balanced flow, and of unresolved small-scale GWs with large-scale, resolved GWs. Models to be developed will lead to a unified parameterization of GWs, from their sources to their dissipation. Both the GW parameterization and global GW permitting and local GW resolving modeling will be used to quantify and mitigate the uncertainties in the understanding of GW impacts on the atmospheric circulation, large-scale dynamical processes in the atmosphere, and climate change. The effort will be based on a close interdisciplinary interaction of mathematics, theory, high-resolution numerical modeling, and measurements of both the wave processes themselves and their effects on the global scale. This combination of methods is employed since only measurements hold the direct link to reality, only theory allows to understand, and since only high-resolution modeling can provide a detailed diagnosis. Such a comprehensive program is far beyond the possibility of a single research institute or some bilateral cooperation but requires a RU with various institutes joining their experimental, computational, and theoretical capabilities. The long-term gains from the RU are to be:- An enhanced and deepened overview of the spatial, temporal and spectral distribution of GWs in the atmosphere.- A significantly improved understanding of the processes causing and controlling the corresponding GW dynamics.- Based on this an increase in the robustness and completeness of the parameterization of GWs as subgrid-scale phenomenon, addressing source processes, GW propagation, GW mean-flow interaction, and GW dissipation.- Hence a more reliable performance of GW parameterizations under anomalous conditions, e.g. climate change.