Questionable Wave Direction Extracted from the ECMWF Database

Ocean wave parameters, especially significant wave height and mean wave direction, are very important in coastal engineering works. Planning and designing coastal structures, such as ports and breakwaters, need such data to accurately configure port components. A need for long-term wave data is increasingly demanded, despite the fact that field measurements of wave climate are expensive and usually unavailable. A reanalysis wave database is a good substitute, yet its reliability must be verified. This study evaluated the wave direction extracted from the Era-interim and Era-5 datasets of the European Centre for Medium-Range Weather Forecasts at two mega ports in Thailand. Ten-year datasets in the months of January and July were used to represent the northeast and southwest monsoons respectively. Our main finding indicated that the direction of wave propagation at both ports during the northeast monsoons was illogical, propagating from the land to the sea, which was highly impossible. If coastal practitioners had utilized the untrustworthy reanalysis wave for their coastal applications, many mistakes would follow, inducing unpredictable economic, environmental, and social damages.