Evaluation of cloud and precipitation processes of NICAM toward a global large-eddy simulation: research activities with NICAM on the supercomputer Fugaku

In this seminar, I first review the current activities of NICAM (Non-hydrostatic Icosahedral Atmospheric Model) using the supercomputer Fugaku. We have been studying the following topics:  1. higher-resolution simulations toward a global large-eddy simulation, 2. multi-decadal 3.5km-mesh simulations,  3. atmosphere-ocean coupled model simulations: 3.5 km x 0.1 deg, 4. large-ensemble monthly simulations (1000 members), and 5. NICAM-LETKF ensemble data assimilations.

I particularly present studies for evaluating the cloud and precipitation processes of NICAM toward a global large-eddy simulation. We obtained the allocation time of Fugaku for a global simulation with a mesh size of about 220 m, which can be viewed as a global large-eddy simulation for deep convective clouds, and we expect that deep convections will be better captured globally. Toward the global 220 m simulations, we conduct a stretched NICAM in which the mesh structure is transformed to obtain finer mesh intervals in the target region. We evaluate cloud microphysics and turbulent schemes using satellite and ground remote sensing observation data under the ULTIMATE (ULTra-sIte for Measuring Atmosphere of Tokyo Metropolitan Environment) project. We also investigate the use of the EarthCARE satellite observation of Doppler motion from space. Because NICAM can be used as both global and regional models, we can immediately test globally using the scheme improved by the stretched NICAM.




Masaki Satoh


Bjorn Stevens

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