Global 7-km mesh nonhydrostatic Model Intercomparison Project for improving TYphoon forecast (TYMIP-G7): Experimental design and preliminary results
Masuo Nakano1, Akiyoshi Wada2, Masahiro Sawada2, Hiromasa Yoshimura2, Ryo Onishi1, Shintaro Kawahara1, Wataru Sasaki1, Tomoe Nasuno1, Munehiko Yamaguchi2, Takeshi Iriguchi2, Masato Sugi2, and Yoshiaki Takeuchi21Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan 2Meteorological Research Institute, Japan Meteorological Agency, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan
Received: 11 Jul 2016 – Accepted for review: 01 Aug 2016 – Discussion started: 02 Aug 2016
Abstract. Recent advances in high-performance computers facilitate operational numerical weather prediction by global hydrostatic atmospheric models with horizontal resolution ~ 10 km. Given further advances in such computers and the fact that the hydrostatic balance approximation becomes invalid for spatial scales < 10 km, development of global nonhydrostatic models with high accuracy is urgently needed.
The Global 7-km mesh nonhydrostatic Model Intercomparison Project for improving TYphoon forecast (TYMIP-G7) is designed to understand and statistically quantify the advantage of high-resolution nonhydrostatic global atmospheric models for improvement of tropical cyclone (TC) prediction. The 137 sets of 5-day simulations using three next-generation nonhydrostatic global models with horizontal resolution 7 km, and conventional hydrostatic global model with horizontal resolution 20 km are run on the Earth Simulator. The three 7-km mesh nonhydrostatic models are the nonhydrostatic global spectral atmospheric Model using Double Fourier Series (DFSM), Multi-Scale Simulator for the Geoenvironment (MSSG), and Nonhydrostatic ICosahedral Atmospheric Model (NICAM). The 20-km mesh hydrostatic model is the operational Global Spectral Model (GSM) of the Japan Meteorological Agency.
Compared with the 20-km mesh GSM, the 7-km mesh models reduce systematic errors of TC track and intensity predictions but still have difficulties in predicting rapid TC intensification. The benefits of the multi-model ensemble method are confirmed to be valid for the 7-km mesh nonhydrostatic global models. Whereas the three 7-km mesh models reproduce a typical axisymmetric mean inner-core structure such as primary and secondary circulations, simulated TC structures and their intensity in each case are very different among the models. Moreover, the simulated track is not always better than that of the 20-km mesh GSM. These results suggest that development of more sophisticated initialization techniques and model physics is needed for further improvement of TC prediction.
Nakano, M., Wada, A., Sawada, M., Yoshimura, H., Onishi, R., Kawahara, S., Sasaki, W., Nasuno, T., Yamaguchi, M., Iriguchi, T., Sugi, M., and Takeuchi, Y.: Global 7-km mesh nonhydrostatic Model Intercomparison Project for improving TYphoon forecast (TYMIP-G7): Experimental design and preliminary results, Geosci. Model Dev. Discuss., doi:10.5194/gmd-2016-184, in review, 2016.