Development and improvement of a nonhydrostatic spectral model using non-constant coefficient semi-implicit and vertically conservative semi-Lagrangian schemes

Yoshimura, Hiromasa

doi:10.5194/gmd-19-10821-2026

Articles | Volume 19, issue 21

https://doi.org/10.5194/gmd-19-10821-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/gmd-19-10821-2026

© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 21

Development and technical paper

|

13 Nov 2026

Development and technical paper |

| 13 Nov 2026

Development and improvement of a nonhydrostatic spectral model using non-constant coefficient semi-implicit and vertically conservative semi-Lagrangian schemes

Hiromasa Yoshimura

Data sets

Yoshimura_Nonhydro_2D_XZ_Testcase Hiromasa Yoshimura https://climate.mri-jma.go.jp/pub/archives/Yoshimura_Nonhydro_2D_XZ_Testcase

Model code and software

Nonhydro_XZ Hiromasa Yoshimura https://doi.org/10.5281/zenodo.17935264

Short summary

We have developed a two-dimensional x–z nonhydrostatic spectral model that achieves high computational efficiency by allowing long timesteps. The model incorporates several improvements that enhance numerical stability and accuracy. The model was tested with various cases, and good results were obtained. The model ran stably even in the case of an extremely steep mountain with an average slope of 63.4°. These improvements will be applied to a global atmospheric model in future work.