Global 7 km mesh nonhydrostatic Model Intercomparison Project for improving TYphoon forecast (TYMIP-G7): experimental design and preliminary results

Abstract

Abstract. Recent advances in high-performance computers facilitate operational numerical weather prediction by global hydrostatic atmospheric models with horizontal resolutions of ∼ 10 km. Given further advances in such computers and the fact that the hydrostatic balance approximation becomes invalid for spatial scales < 10 km, the development of global nonhydrostatic models with high accuracy is urgently required.The Global 7 km 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. A total of 137 sets of 5-day simulations using three next-generation nonhydrostatic global models with horizontal resolutions of 7 km and a conventional hydrostatic global model with a horizontal resolution of 20 km were run on the Earth Simulator. The three 7 km mesh nonhydrostatic models are 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). 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 in the TC track, intensity and wind radii predictions. The benefits of the multi-model ensemble method were confirmed for the 7 km mesh nonhydrostatic global models. While the three 7 km mesh models reproduce the typical axisymmetric mean inner-core structure, including the primary and secondary circulations, the simulated TC structures and their intensities in each case are very different for each model. In addition, the simulated track is not consistently better than that of the 20 km mesh GSM. These results suggest that the development of more sophisticated initialization techniques and model physics is needed to further improve the TC prediction.

Robust Enhancement of Tropical Convective Activity by the 2019 Antarctic Sudden Stratospheric Warming

“…Running similar numerical experiments using cloud-resolving models are promising for reducing the uncertainty in the tropical convective response to SSWs. Advances in high-performance computers enable the nonhydrostatic model intercomparisons with horizontal resolutions <10 km (e.g., Nakano et al, 2017). Further investigations, possibly a comparison of ensemble cloud-resolving model simulations, are envisaged as an extension of this study.…”

Global Cloud-Resolving Models

“…NICAM has also been evaluated in more realistic/ operational settings for studies of the MJO [84], tropical cyclones (TYMIP-G7 [85]), and contributed to the Athena Project [86] in which it was compared to higher resolution hydrostatic integrations with IFS [87]. For operational models, the High Impact Weather Prediction Project (HIWPP; https:// hiwpp.noaa.gov/) was coordinated by the National Oceanographic and Atmospheric Administration (NOAA) in the USA, to prepare GCRMs for use operationally.…”

Evaluation of FAMIL2 in Simulating the Climatology and Seasonal‐to‐Interannual Variability of Tropical Cyclone Characteristics

“…By both regional and global model experiments, many studies claim nonhydrostatic dynamic core in a superhigh horizontal resolution plays a crucial role for the intensity of TC simulation. (e.g., Nakano et al, 2015Nakano et al, , 2017Satoh et al, 2014). Finally, the role the air-sea interaction as well as the model physics modules have been shown to be connected to the bias of the intensity and structure of TC simulation, especially the maximum wind speed (e.g., Mogensen et al, 2017;Srinivas et al, 2016;Zarzycki, 2016).…”

“…In terms of scientific analysis, it is necessary to discuss the simulated TC activity under superhigh resolution conditions. For example, Japanese scientists launched the Global 7-km Mesh Non-hydrostatic Model Intercomparison Project for Improving Typhoon Forecasts (or TYMIP-G7, for short; Nakano et al, 2017). Preliminary results have shown enormous improvement in TC simulation and forecasting by using a nonhydrostatic dynamical core at ultrahigh resolution (<10 km).…”