Development and evaluation of an ensemble forecasting system for regional ocean wave at KMA

Abstract:

KMA developed an ensemble forecasting system for regional wave. The system predicts ocean (wind) waves based on meteorological forcing from the KMA-EPSG (Ensemble Prediction System for Global at KMA), which has been running twice per day on experiment. It consisted of 24 ensemble members including the control member. It made 87 hour forecasts for 00 and 12 UTC each day. Its spatial resolution is 0.083° in latitude and longitude from 115E to 150E and from 20N to 50N regionally. The wind forcing for the 24 ensemble members are obtained from KMA-EPSG 10m wind fields and are updated every three hours.
Hereafter, the ensemble ocean wave forecasts will be evaluated using moored buoy data from 8 locations around the coast of South Korea. Statistical verification will be performed for the typhoon cases during summer in 2015. The RMSE (Root Mean Square Error) is calculated for four types of forecasts: the ensemble control, the perturbed ensemble members, the mean of all ensemble members (including the control), and the existing operational deterministic waves forecasts. Also, this study will be conducted probability analysis such as brier score (BS), economical value on the performance of the system.