Three Dimensional Numerical Simulations of Tornadoes

[9521759]费德勒龙卷风被认为是最猛烈的局部天气现象之一。在过去几年中，在了解龙卷风雷暴的结构和龙卷风涡旋的动力学方面取得了很大进展。然而，关于龙卷风旋涡内部子结构的动力学以及龙卷风特征与当地环境之间的关系，仍然存在未解之谜。在这项研究中，龙卷风将使用非常先进的三维数值模型进行模拟。所使用的模型能够连续动态网格自适应，并且非常适合在建模域的相对较小区域内解决需要增强分辨率的移动实体。该项目的目标是确定龙卷风的最大风速与环境条件的关系，如对流有效势能和龙卷风底部的径向流入。计划中的数值模拟也将允许对不对称涡旋破裂、不稳定性、湍流输送和多重涡旋进行研究。这项研究的结果将有助于更好地理解龙卷风特别猛烈的下层结构（例如卫星涡），并最终提高预测这种现象的能力。＊＊＊

9521759 Fiedler Tornadoes are recognized as one of the most violent, localized weather phenomena. Much progress has been made over the last several years in understanding both the structure of tornadic thunderstorms and the dynamics of tornado vortices. There still, however, are unanswered questions as to the dynamics of substructures contained within a tornadic vortex and the relationship between the tornado s characteristics and the local environment. In this research, tornadoes will be simulated using a very advanced three-dimensional numerical model. The model to be used is capable of continuous dynamic grid adaptation and is ideally suited for resolving moving entities requiring enhanced resolution in a relatively small region of the modeled domain. The project goal is to determine how the maximum wind speed in a tornado is related to environmental conditions, such as convective available potential energy and radial inflow at the base of the tornado. The planned numerical simulations also will allow a study of asymmetric vortex breakdown, instabilities, turbulent transport and multiple vortices. The results of this research should lead to a better understanding of the especially violent substructures of tornadoes (e.g. satellite vortices) and eventually enhance the ability to predict such phenomena. ***