1.Particle-Based Cloud Modeling using the Super-Droplet Method
The super-droplet method (SDM) is a particle-based numerical algorithm that enables accurate simulation of cloud microphysics with lower computational demand (Shima et al., 2009). We are developing a highly accurate cloud model using the SDM, which will contribute to reducing the uncertainties of numerical weather prediction and climate simulation.  We are also interested in applying the methodology to other research areas, such as volcanic fumes, star formation, and spray combustion.

Precipitation from a shallow maritime cumulus (2D simulation). Click the figure to see the movie.

VR movie of a cumulus congestus, created by our collaborator Dr. Toshiki Matsushima (R-CCS).

2.Synchronization Phenomena
Self-sustained oscillators can generate macroscopic rhythms as a collective through their mutual interaction. This is referred to as synchronization phenomenon or rhythmic phenomenon. Various things are known to synchronize, ranging from mechanical ones such as metronomes, to biological ones such as heart cells, circadian rhythms, crowd clapping, firefly flashingh, and croaking of frogs.

Simulation of the collective synchronous flashing of fireflies

3.Micro-Macro Interlocked Simulation
Physical laws have a hierarchical structure. As a result, both micro and macroscopic domains may coexist in a phenomena simultaneously. Leveraging this characteristic, the Micro-Macro Interlocked Simulation methodology aims to simulate the macroscopic behavior of the phenomena of interest efficiently and accurately .

Micro-Macro Interlocked simulation of two phase singularities with attractive interaction. (a) result of the first-principle calculation. (b) and (c) result of the Micro-Macro Interlocked simulation.  The red domain indicated in (c) is simulated microscopically in (b).

4.Data Assimilation of Complex Systems
データ同化とは, 不確かさを伴うシミュレーションと観測を融合し, そこからより確かな情報を抽出する統計学的枠組みです. 社会・産業・環境に関する複雑な現象のシミュレーションにデータ同化を応用する研究を行っています.


Master's Thesis
・Simulation of precipitating staratocumlus over Tokyo using the super-droplet method
・Wake-induced CCN-activation behind precipitation particles
・Implementation of spontaneous breakup process to the super-droplet method
・Simulation of rain in cumulus congestus over tropical ocean using the super-droplet method
・Two-dimensional idealized simulation of orographic snow clouds in Hokuriku using the super-droplet method
・Numerical analysis of the wall adhesion and flow characteristics of micro droplets in oil mist separator
・Improvement of ice crystal growth model and the assessment of its impact to cumulonimbus simulation
・Numerical study of the impact of aerosol regeneration process on orographic clouds and precipitation using the super-droplet method