Validation of significant wave height from Jason-3 and Sentinel-3A/B and relation to tidal currents in coastal regions of the Korean Peninsula

Abstract

As climate change and oceanic warming have an increasing impact on coastal waves, accurate observation of satellite significant wave height (SWH) in coastal regions is becoming more important. In addition to the validation of satellite SWHs in the global ocean, the SWHs should also be validated in coastal regions for their diverse applications. In this study, the accuracy and error characteristics of altimeter SWH data, Jason-3 Geophysical Data Records Version D and Sentinel-3A/B Level-2 marine scientific products, were investigated using SWH measurements from 18 buoy stations in the coastal region of the Korean Peninsula from 2017 to 2019. Results showed that the Jason-3 and Sentinel-3A/B SWHs exhibited root mean square errors (RMSE) and bias errors of 0.59-1.60 m and 0.03-0.42 m, respectively. Cross-validation between Jason-3 and Sentinel-3A/B exhibited a consistency comparable to that of the global ocean. The spatial distribution of comparison between altimeter SWH and wave model data was similar to that obtained using altimeter SWH and in situ measurements. Validation of altimeter SWH from the buoy stations yielded the highest error in the southwestern coastal region of the Korean Peninsula, with high tidal currents in the Yellow Sea. The stronger the tidal current speed, the more amplified the satellite SWH errors. The SWH differences exhibited a high dependence on the tidal index, including the elements of tidal current speed, water depth, and tide height. A relationship was found between the tidal index and the altimeter SWH differences from the in situ measurements. Based on this relation, formulas were proposed to reduce satellite SWH errors due to tidal currents in the coastal regions of the Korean Peninsula. For the matchups with tidal index less than 2, RMSE and bias errors of each satellite sensor were improved by up to 14.25% (0.28 m) and 94.40% (0.84 m), respectively.