Global 7km Mesh Nonhydrostatic Model Intercomparison Project for Improving TYphoon Forecast (TYMIP-G7): Joaquin (2015) and Lionrock (2016) Cases

The Global 7km mesh nonhydrostatic Model Intercomparison Project for improving TYphoon forecast (TYMIP-G7) is designed to understand and statistically quantify the advantages of high-resolution nonhydrostatic global atmospheric models to improve tropical cyclone (TC) prediction. The three 7km mesh nonhydrostatic models, the nonhydrostatic global spectral atmospheric Double Fourier Series Model (DFSM), the Multi-Scale Simulator for the Geoenvironment (MSSG) and the Nonhydrostatic ICosahedral Atmospheric Model (NICAM), and one 20km mesh hydrostatic model is the operational Global Spectral Model (GSM) of the Japan Meteorological Agency are participating the project. So far, Nakano et al (2017, GMD) have shown that the 7km mesh models reduce systematic errors in the TC track, intensity and wind radii predictions.

Recently, two series of simulation for Hurricane Joaquin (2015) and Typhoon Lionrock (2016) were conducted. Lionrock experiments were initialized by using 12 hourly JMA operational global analysis from 1200 UTC 22 August to 0000 UTC 26 August. The results show that GSM, DFSM and NICAM could simulate recurvature of Lionrock towards the Japanese Islands and the Northwest China. MSSG, however, tended to simulate the track further northeastward. GSM, DFSM and NICAM could simulate rapid intensification of the typhoon but the simulated typhoon tended to intensify excessively.

The 7-km simulations were compared with operational medium-range forecasts taken from TIGGE to investigate the cause of differences in simulated tracks. The results suggest that the interaction between Lionrock and the upper trough in the mid-latitude is crucial for successfully simulating the change of the moving direction of Lionrock towards the Japanese Islands and the Northwest China.

We will also present the result of Joaquin’s case.