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 which have atmospheres on a certain parameter space and investigating changes in the behavior of the atmospheric circulation in the parameter space by numerical calculation, 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.
In addition, we perform high-resolution simulations of the Venusian and the Martian atmospheres with super computers, such as the K computer and the Earth Simulator, and we also analyze the obtained enormous amount of data.
Because a planetary atmospheric circulation consists of phenomena in varuos scales and they interact with each others, the high-resolution simulation mimics the real atmosphere more precisely, which will greatly helps us in understanding the atmospheric circulation.
On the other hand, unlike the Earth atmosphere, where the observations are spatiotemporally dense, an 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
High-resolution simulations of Mars and Venus atmospheres
Depencecies of GCM results on basic equations and numerical methods
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.
Ando, H., N. Sugimoto, M. Takagi, H. Kashimura, T. Imamura, and Y. Matsuda (2016), The puzzling Venusian polar atmospheric structure reproduced by a general circulation model. Nature Communications, 7, 10398.
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.
Yamamoto, H., K. Ishioka, and S. Yoden (2009), Axisymmetric Steady Solutions in an Idealized Model of Atmospheric General Circulations: Hadley Circulation and Super-rotation. Theoretical and Applied Mechanics Japan, 57, 147-158.
(H. Kashimura is formerly known as H. Yamamoto.)
Meteorological Society of Japan
The Japanese Society for Planetary Sciences
Society of Geomagnetism and Earth, Planetary and Space Sciences