10:00 AM - 10:15 AM
[MIS24-05] Numerical experiments of surface flows on giant planets produced by forcings representing thunderstorms
Keywords:Jovian planets, Banded structure, Polar vortex, Shallow water model
It is known that the surfaces of giant planets have the banded structures consisting of equatorial jets with wide latitudinal widths and mid-latitudinal jets with narrow latitudinal widths, and the vortex structures in the polar regions.Large-scale structures such as banded structures and polar vortices can be formed from small-scale turbulence due to the inverse cascade effect (e.g. Showman et al., 2009). Thunderstorms are considered to be a candidate for causing such small-scale turbulence (e.g. Ingersoll et al., 2000).
Showman (2007) and Brueshaber et al. (2019) performed calculations in the framework of the shallow water system with the mass forcing representing thunderstorms. Showman (2007) showed the formation of the banded structures with restricting the computational domain to the latitude range 0-70 degrees and the longitude range of 0-120 degrees. Brueshaber et al. (2019) found the polar vortex structures were formed in the computational domain from latitude 60 degrees to high latitude. In addition, their results showed that the number and size of polar vortices, and the sign of vorticity significantly depend on the value of Burger number (Bu=(Ld/a)2, Ld: deformation radius, a: planetary radius). However, computational domains used by previous studies are restricted to a part of the sphere. In cases of calculation by regional model, the structure of jets and vortices may change due to momentum transport from regions outside the restricted computational domain.
The purpose of this study is to perform global calculations and to investigate whether the jet and polar vortex structures can be formed by the mass forcing representing thunderstorms. These structures are compared with the results obtained in previous studies to validate the domain calculations. The model used in this study is the Hierarchical Spectral Models for GFD (SPMODEL; Takehiro et al. 2006, Takehiro et al. 2013). The used equations are 1.5-layer shallow water equations with the mass forcing representing thunderstorms. The experiments are performed with changing values of the Burger number. In this presentation, the results of numerical experiments and the consistency with previous studies will be reported.
Showman (2007) and Brueshaber et al. (2019) performed calculations in the framework of the shallow water system with the mass forcing representing thunderstorms. Showman (2007) showed the formation of the banded structures with restricting the computational domain to the latitude range 0-70 degrees and the longitude range of 0-120 degrees. Brueshaber et al. (2019) found the polar vortex structures were formed in the computational domain from latitude 60 degrees to high latitude. In addition, their results showed that the number and size of polar vortices, and the sign of vorticity significantly depend on the value of Burger number (Bu=(Ld/a)2, Ld: deformation radius, a: planetary radius). However, computational domains used by previous studies are restricted to a part of the sphere. In cases of calculation by regional model, the structure of jets and vortices may change due to momentum transport from regions outside the restricted computational domain.
The purpose of this study is to perform global calculations and to investigate whether the jet and polar vortex structures can be formed by the mass forcing representing thunderstorms. These structures are compared with the results obtained in previous studies to validate the domain calculations. The model used in this study is the Hierarchical Spectral Models for GFD (SPMODEL; Takehiro et al. 2006, Takehiro et al. 2013). The used equations are 1.5-layer shallow water equations with the mass forcing representing thunderstorms. The experiments are performed with changing values of the Burger number. In this presentation, the results of numerical experiments and the consistency with previous studies will be reported.