Improvement of Fine-mesh Numerical Meteorological Modeling

研究人员将攻击一个基本的，但未解决的问题，在大气和海洋科学的数值模拟-适当的公式在数值模型的亚网格尺度湍流时，在数值模型的网格大小的规模（d）是的含能量的湍流（L）的规模的顺序。 目前的中尺度模式倾向于包含多年前提出的涡动扩散率模式，当d远大于L时，这种近似是足够的。 然而，研究小组的初步工作表明，当d接近L时，需要新的公式。 研究人员将首先在高分辨率大涡模拟（LES）模型中安装新的公式。 他们将在大气边界层（ABL）模拟中将标量和速度统计与标准和新公式进行比较。 由于两组结果不应有显著差异，这提供了一个模式验证测试。研究人员将把新的公式安装到一个先进的中尺度模式中，并研究对湿对流模拟的影响。 他们还将继续模拟ABL流。 我们的目标是记录新模型的性能，因为d接近L.这项工作预计将影响数值模拟的应用程序中的网格尺寸是湍流的规模的顺序。 这发生在从区域天气预报到模拟严重风暴和飓风的高分辨率气象建模中。

The investigators will attack a basic but unsolved problem in numerical modeling in the atmospheric and oceanic sciences -the proper formulation in a numerical model of the subgridscale turbulence when the scale of the grid size in the numerical model (d) is of the order of the scale of the energy-containing turbulence (L). Current mesoscale models tend to contain eddy-diffusivity models of the type proposed many years ago and this approximation was adequate when d was much greater than L. Preliminary work by the research team has revealed, however, that new formulations are required as d approaches L. The investigators will first install the new formulation in a high-resolution large eddy simulation (LES) model. They will compare the scalar and velocity statistics obtained with the standard and new formulation in atmospheric boundary-layer (ABL) simulations. Since the two sets of results should not be significantly different, this provides a model validation test.The investigators will then install the new formulation into an advanced mesoscale model and study the impact on simulations of moist convection. They will also continue the simulations of ABL flows. The goal is to document the performance of the new model as d approaches L.The work is expected to impact numerical modeling in applications where the grid mesh size is of the order of the scale of the turbulence. This occurs in high resolution meteorological modeling in applications ranging from regional weather prediction to simulations of severe storms and hurricanes.