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NLT3D: a non-local three-dimensional turbulence parameterization scheme for next generation numerical weather prediction models

NLT3D：下一代数值天气预报模型的非局部三维湍流参数化方案

基本信息

批准号：
393813204
负责人：
Professor Dr. Andreas Bott
金额：
--
依托单位：
Abteilung Meteorologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2018
资助国家：
德国
起止时间：
2017-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/393813204?language=en
关键词：
NLT3D non local three dimensional

项目摘要

Numerical weather prediction models have to split the atmospheric processes into two classes: processes on spatial scales larger than the grid size can be simulated explicitly by the basic equations (conservation laws), while subgrid scale processes have to be represented by physical parameterization schemes. With increasing computer power many national forecast centers now aim at horizontal grid sizes in the kilometer and subkilometer range to be operationally available in the next years. Since most parameterization schemes used in forecast models have been developed for horizontal grid sizes of several kilometers and more, their formulation and selection of processes included will then become questionable. This holds especially for the turbulence parameterization representing subgrid scale dynamics and transport mainly in the planetary boundary layer (PBL). Since here the exchange of energy, momentum, moisture and other trace gases with the earth's surface takes place, a correct simulation of the PBL processes is decisive for a good forecast quality. Since the most energetic large eddies in the boundary layer cannot be represented by classical K approaches simulating local mixing by small eddies, non-local (but still one-dimensional) turbulence schemes have been developed to account for smaller vertical grid sizes. On the other hand, small grid sizes in the horizontal direction now also claim the representation of horizontal turbulent exchange between the grid boxes, i.e. the simulation of three-dimensional (3D) turbulence. To overcome these problems, we plan to develop a non-local parameterization scheme for 3D turbulence by extending an existing non-local one-dimensional turbulence parameterization by a horizontal turbulent exchange. As a model environment for development and testing of our scheme we will use the WRF model from UCAR/NCAR, USA. However, the algorithms in the scheme will be formulated in a way allowing for implementation in other high resolution forecasting models as well.

数值天气预报模式必须将大气过程分为两类：大于网格尺寸的空间尺度过程可以通过基本方程（守恒定律）显式模拟，而次网格尺度过程必须通过物理参数化方案表示。随着计算机能力的提高，许多国家的预报中心现在的目标是在未来几年内将水平网格的尺寸提高到千米和亚千米范围。由于预报模式中使用的大多数参数化方案都是为几公里或更大的水平网格尺寸开发的，因此它们的公式和所包含过程的选择将变得有问题。这尤其适用于代表次网格尺度动力学和主要在行星边界层（PBL）中的传输的湍流参数化。由于能量、动量、水分和其他痕量气体在这里与地球表面交换，因此正确模拟边界层过程对于良好的预报质量是决定性的。由于边界层中能量最大的大涡不能用模拟小涡局部混合的经典K方法来表示，因此已经开发了非局部（但仍然是一维）湍流方案来考虑较小的垂直网格尺寸。另一方面，水平方向上的小网格尺寸现在也要求网格框之间的水平湍流交换的表示，即三维（3D）湍流的模拟。为了克服这些问题，我们计划开发一个非局部的三维湍流参数化方案，通过扩展现有的非局部一维湍流参数化水平湍流交换。作为一个模型环境的开发和测试我们的计划，我们将使用WRF模型从UCAR/NCAR，美国。然而，该方案中的算法将以允许在其他高分辨率预测模型中实现的方式来制定。