Development of a cloud-resolving model based on the building cube method

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K13881
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Meteorology/Physical oceanography/Hydrology
• Research Institution: Kyoto University
• Principal Investigator: Shige Shoichi 京都大学, 理学研究科, 准教授 (60344264)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 雲解像モデル / 直交格子積み上げ法

Outline of Final Research Achievements

We developed a cloud-resolving model to simulate tropical precipitation systems efficiently based on the building cube method, which divided the computational region into cubes that can have different resolution. In our cloud-resolving model, the high resolution cube represents the lower layer where the eddy scale is small, and the low resolution cube represents the higher layer where the eddy scale is large. This representation based on the building cube method leads to decreasing the number of cells and simulating the development of convection efficiently. A warm bubble test and a 2D squall line test showed that our cloud-resolving model succeeded in decreasing the computational cost by decreasing the number of cells with the building cube method, and can simulate development of convection efficiently by locally increasing the resolution in the lower layer.

Free Research Field

大気物理学

Academic Significance and Societal Importance of the Research Achievements

本研究で開発した直交格子積み上げ法を採用した雲解像モデルは水平解像度を鉛直方向に一定・不変とする従来の大気モデルとは大きく異なり、雲の発達の再現に重要な下層の解像度を局所的に高めることを可能にする。特に3次元実験では2次元実験に比べて計算コストが大幅に増加するため、本研究で開発した雲解像モデルを3次元化することで計算コストの改善はより効果的となると考えられる。計算コストを抑えつつ下層の解像度を高めた実験が可能となるためより広い領域を対象とした実験を可能にし、次世代の全球雲解像モデル開発の起点となり、雲解像モデルを用いた様々な降水システムの特性解明や予報に寄与する。