Seminar: CPS Seminar
date: 2022 June 24 (FRI) 17-19:00
Room: Online seminar (Zoom)
Speaker: TOMITA Hirofumi (RIKEN Center for Computational Science)
Title: "Model development from the global cloud resolving model to the global large eddy simulation model"
Abstract: In the 2000s, the atmospheric model evolved from hydrostatic equilibrium models to non-hydrostatic models. Implementing the cloud microphysics process on a global non-hydrostatic model, we directly resolved clouds with better expression for hierarchical structures from convective cloud scales to large-scale scales. However, the indirect effect of aerosols, one of the significant causes of uncertainty in climate projection, has not yet been expressed by such a global cloud resolving model with a grid spacing of several kilometers. If we aim for a further qualitative jump in the model in the future, it will be a global large eddy simulation (LES) model that can estimate such effects. In fact, it is recognized that the expression of "shallow clouds" related to the above effect can be well reproduced in numerical experiments using a regional LES model with a grid spacing of several meters to several tens of meters. On the other hand, it is highly doubtful whether the current LES used in the meteorological model is consistent with the theory.

In this presentation, I would like to share and recognize various issues regarding the global LES model. To break through the development of next-generation models, it will be necessary to carefully solve not only the problems of LES itself but also the problems that have been left behind. It's time to challenge them again. At the same time, it is also necessary to return to a simple experimental setting once in the development process. Recently, the climate team in RIKEN has been working on ideal experiments where the self-aggregation and hierarchical structure of clouds are focused. Reporting on their recent new findings, I would like to discuss the prospects for future model development with my personal opinion.
Keywords: global model, large eddy simulation, sef-organization
Organizer: MAKINO Junichiro