Power difference of the relationship formula between significant wave height and wind speed in Taiwan waters

The relationship between significant wave height and wind speed has been extensively studied for a long time. Previous studies have indicated a relationship between these two variables. The relationship can be expressed as the significant wave height proportional to the square of the wind speed or through a scaling exponent. Taiwan is an island located in the Western Pacific. The northeast monsoon prevails in winter, while the southwest monsoon dominates in summer. The wind speed in the former is stronger than that in the latter. To gain insights into the marine conditions surrounding Taiwan, the Central Weather Administration of Taiwan has deployed several mooring buoys in some waters to collect wind and wave data. This study utilized data from these buoys to derive the most applicable wind-wave relationship for the waters surrounding Taiwan. The results show that under northeasterly winds, the significant wave height is related to the 0.81 power of wind speed in the northeastern waters of Taiwan, 0.95 power in the western waters, 1.29 power in the southwestern waters, and 0.94 power in the eastern waters. These exponents are notably lower than those of the quadratic law applicable to fully developed waves. Under north-northeast winds, the same relationship exists in the northeastern and southwestern waters, but not in the western and eastern waters. This may be attributed to the influence of coastal topography on wave generation and propagation dynamics. The analysis also found that only the northeast wind and north-northeast wind follow the power relationship, while other wind directions do not.