The Track and Accompanying Sea Wave Forecasts of the Super Typhoon Mangkhut (2018) by a Real-time Regional Forecast System

Abstract

The track and accompanying sea wave forecasts of the typhoon Mangkhut (2018) by a real-time regional forecasting system are assessed in this study. The real-time regional forecasting system shows a good track forecast skill with a mean error of 69.9 km for the forecast period of 1-72 h. In particular, it well predicted the landfall location in the coastal island of South China with distance (time) biases of 76.89 km (3 h) averaging over all forecasting made during 1-72 h and only 3.55 km (1 h) for the forecasting initialized 27 h ahead of the landfall. The sea waves induced by Mangkhut (2018) were also well predicted by the wave model of the forecasting system with a mean error of 0.54 m and a mean correlation coefficient up to 0.94 for the significant wave height. Results from sensitivity experiments show that the improvement of track forecasting skill for Mangkhut (2018) mainly attributes to the application of the Scale-Selective Data Assimilation (SSDA) scheme in the atmosphere model which helps to maintain a more realistic large-scale flow obtained from the GFS forecasts, whereas the air-sea coupling has slightly negative impact on the track forecast skill.