Comparison of ECMWF Significant Wave Height Forecasts in the China Sea with Buoy Data

Abstract

Abstract This paper focuses on a comprehensive comparison of the European Centre for Medium-Range Weather Forecasts (ECMWF) significant wave height (SWH) forecasts with buoy data in the China Sea, and analysis of accuracy characteristics varying with related variables (SWH, water depth, and distance from shore) and different scenarios (each month, different sea area, and typhoon- and cold air activity–induced waves). This is the first time that observations from the Chinese Ocean Monitoring Network have been used to verify ECMWF wave forecasts in the China Sea. Two years’ worth of data from 24 hydrometeorological buoys are used. The comparison shows good accuracy and predictive stability of SWH forecasts for the Chinese buoys, which is consistent with Korean and global buoys. However, the accuracy in the Bohai Sea and Taiwan Strait is worse than that in the South and East China Sea. SWH forecasts for QF206 in the southern Taiwan Strait have systematically underestimated observations, which may be mainly due to the coarse resolution of wave forecasts. Besides, forecasts underestimate observations when 1.5 m < SWH ≤ 6.5 m. The accuracy and predictive stability in spring and summer are worse than those in winter, especially in April, which is the worst in 12 months. The accuracy increases with water depth and distance from shore. During typhoon conditions, the accuracy is worse than during cold air conditions.