My research interest is to understand the dynamics of atmospheric circulations on various planets and satellites in a unified way.
By locating solar system celestial bodies that have atmospheres on a certain parameter space and investigating changes in the behavior of the atmospheric circulation in the parameter space by numerical simulations, different structures of the atmospheric circulation can be explained by the dependence on a few parameters.
For such studies, we develop numerical models of the planetary atmospheres and construct/investigate theoretical models to explain the behavior of numerical solutions.
Also, we perform high-resolution simulations of the Venusian and the Martian atmospheres using such as the supercomputer Fugaku and the Earth Simulator, and we analyze the obtained enormous amount of data.
Because a planetary atmospheric circulation consists of phenomena on various scales and they interact with each other, the high-resolution simulation mimics the real atmosphere more precisely, which will significantly help us in understanding the atmospheric circulation.
On the other hand, unlike the Earth's atmosphere, where the observations are spatiotemporally dense, the amount of observational data to be referenced is very small in simulations of the Venusian and the Martian atmospheres.
Hence, well understanding of the dependence of numerical models on the basic equations and numerical methods is also important to know whether results of the high-resolution simulation are physically valid or not.
Main Research Themes:
Numerical and theoretical studies of general circulations of planetary atmospheres
Development of a non-hydrostatic global model for planetary atmospheres
High-resolution simulations of Mars and Venus atmospheres
Recent Publications:
Sugimoto, N., Y. Fujisawa, N. Komori, H. Kashimura, M. Takagi, and Y. Matsuda (2023), Super-rotation independent of horizontal diffusion reproduced in a Venus GCM. Earth, Planets and Space, 75, 44, https://doi.org/10.1186/s40623-023-01806-7.
Sugimoto, N., Y. Fujisawa, H. Kashimura, K. Noguchi, T. Kuroda, M. Takagi, and Y.-Y. Hayashi (2021), Generation of gravity waves from thermal tides in the Venus atmosphere. Nature Communications, 12, 3682, doi.org/10.1038/s41467-021-24002-1.
Kodama, C., A. Kuwano-Yoshida, S. Watanabe, T. Doi, H. Kashimura, and T. Nasuno (2019), JAMSTEC Model Intercomparison Project (JMIP). JAMSTEC Rep. Res. Dev., 28, 5-34, doi.org/10.5918/jamstecr.28.5.
Kashimura, H., N. Sugimoto, M. Takagi, Y. Matsuda, W. Ohfuchi, T. Enomoto, K. Nakajima, T. M. Sato, G. L. Hashimoto, T. Satoh, Y. O. Takahashi, and Y.-Y. Hayashi (2019), Planetary-scale streak structure reproduced in high-resolution simulations of the Venus atmosphere with a low-stability layer. Nature Communications, 10(23), 1-11, doi.org/10.1038/s41467-018-07919-y.
Kashimura, H., M. Abe, S. Watanabe, T. Sekiya, D. Ji, J. C. Moore, J. N. S. Cole, and B. Kravitz (2017), Shortwave radiative forcing, rapid adjustment, and feedback to the surface by sulphate geoengineering: Analysis of the Geoengineering Model Intercomparison Project G4 scenario. Atmos. Chem. Phys., 17(5), 3339-3356, doi:10.5194/acp-17-3339-2017.
Kashimura, H. and S. Yoden (2015), Regime Diagrams of Solutions in an Idealized Quasi-Axisymmetric Model for Superrotation of Planetary Atmospheres. Journal of the Meteorological Society of Japan, 93(2), 309-326.
Kashimura, H., T. Enomoto, and Y. O. Takahashi (2013), Non-negative filter using arcsine transformation for tracer advection with semi-Lagrangian scheme. SOLA, 9, 125-128, doi: 10.2151/sola.2013-028.
Yamamoto, H. and S. Yoden (2013), Theoretical Estimation of the Superrotation Strength in an Idealized Quasi-Axisymmetric Model of Planetary Atmospheres. Journal of the Meteorological Society of Japan, 91(2), 119-141.
(H. Kashimura is formerly known as H. Yamamoto.)
Academic Associations:
Meteorological Society of Japan
The Japanese Society for Planetary Sciences
Society of Geomagnetism and Earth, Planetary and Space Sciences