Nonlinear Atmospheric Adjustment

首席研究员将研究广义大气强迫的非线性大气调整。大气调整被定义为湿润的、可压缩的大气对规定强迫的响应。在一个任意形状的瞬时强迫之后，大气一般会立即处于地转和流体静力不平衡的状态。大气平差的研究描述了随后空气达到地转和静水平衡状态的趋势。它是地转调整的经典问题的延伸，包括可压缩性的影响，并允许非流体静力和潮湿过程。所研究的强迫将完全是一般的，包括动量、质量、热量和水分强迫。因此，这项研究将深入了解大气的基本运作，以及云、中尺度对流系统和其他由潮湿对流驱动的非流体静力环流的具体动力学。虽然加热和润湿都对应于对气团的浮力的增加，但它们有一个根本的区别。增加的热量可以转化为其他形式的能量，这些能量可以传播出去；添加的水必须被保存，不能被转化（在没有相变的情况下）并传播出系统。在数值天气预报模式中，对垂直动量注入的响应将有助于深入了解上升气流的初始化。一组非线性数值问题将用于检验可压缩性对广义力调整的全部影响。数值模型将以线性平差问题的解析解为基准。更广泛的影响包括训练研究生运行和测试数值模型，以及在专业会议和期刊文章中撰写和交流科学研究。它还包括可以在课堂上传播给本科生和研究生的知识，以及通过更好地理解大气调节及其对数值天气预报和潮湿对流的影响而产生的社会效益。

The Principal Investigator will investigate nonlinear atmospheric adjustment to generalized atmospheric forcing. Atmospheric adjustment is defined as the response of a moist, compressible atmosphere to a prescribed forcing. Immediately after an instantaneous forcing of arbitrary shape, the atmosphere will, in general, be in a state of geostrophic and hydrostatic imbalance. The study of atmospheric adjustment describes the subsequent tendency of the air to achieve a state of geostrophic and hydrostatic balance. It is an extension of the classic problem of geostrophic adjustment to include the effects of compressibility and to allow for nonhydrostatic and moist processes. The forcings studied will be completely general and include momentum, mass, thermal, and moisture forcings. Thus, the research will provide insight into the fundamental workings of the atmosphere as well as into the specific dynamics of clouds, mesoscale convective systems, and other nonhydrostatic circulations driven by moist convection. Although both heating and moistening correspond to an addition of buoyancy to the air mass, there is a fundamental difference. An addition of heat can be transformed to other forms of energy that can be propagated away; an addition of water must be conserved and cannot be transformed (in the absence of phase changes) and propagated out of the system. The response to injections of vertical momentum will gain insight into the initialization of updrafts in numerical weather prediction models. A suite of nonlinear numerical problems will be used to examine the full effects of compressibility in the adjustment to generalized forcings. The numerical models will be benchmarked against analytic solutions to the linear adjustment problem. The broader impacts include the training of graduate students in the running and testing of numerical models and in the writing and communicating of scientific research at professional meetings and in journal articles. It also includes the knowledge gained that can be disseminated to the undergraduate and graduate students in the classroom and the societal benefit through a better understanding of atmospheric adjustment and its implications to numerical weather prediction and moist convection.