The long-term trend of swell-like waves invading the east coast of Korea was identified by using observations and hindcast data from 1979 to 2016. We defined a swell-like wave as a wave with a height of 2 m and a peak period of 10 s on the basis of a literature review of human casualties and property damage in the region. In total, 179 swell-like wave cases were detected from 1979 to 2016, with 132 cases caused by extratropical cyclones (ETCs). The track density analysis indicated that the ETCs were mainly generated on the east coast of China, over the East/Japan Sea, and over the Kuroshio-Oyashio extension region and then moved northeast. This reflects the prevailing wind direction, which was the most significant factor in generating the swell-like waves. The number of swell-like waves has been significantly increasing since the 2000s. This increasing trend of swell-like waves is linked with the synoptic eddy activity with a correlation of 0.53. They were associated with the reversed meridional gradient of surface air temperature and the consequent negative vertical wind shear anomaly near 40° N.

Heo, K.-Y.; Choi, J.-Y.; Jeong, S.-H., and Kwon, J.-I., 2020. Characteristics of high swell-like waves on east coast of Korea observed by direct measurements and reanalysis data sets. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1433-1437. Coconut Creek (Florida), ISSN 0749-0208.Characteristics of high swell-like waves occurred at the east coast of Korea were analyzed using the wave observation data, high-resolution atmospheric dynamical downscaling of ERA-Interim using weather research and forecasting (WRF) model, and wave reanalysis using the SWAN model. The favorable synoptic conditions are classified into three types: the west high east low (WHEL), extratropical cyclone (EC), and tropical cyclone (TC). From 1979 to 2018, the WHEL, EC, and TC types accounted for 66%, 15%, and 18%, respectively, of the total synoptic patterns causing the swell-like wave. Most swell-like waves have a common feature in the generation of strong northwest winds due to a strong pressure gradient from the low pressure system over the East Sea.

The parametric typhoon model is a powerful typhoon prediction and reproduction tool with advantages in accuracy, and computational speed. To simulate typhoons’ horizontal features, the longitude and latitude of the typhoon center, central pressure, radius of maximum wind speed (Rmax), and background states (such as surface air pressure and wind speed) are required. When a typhoon approaches or is predicted to affect Korea, the Korea Meteorological Agency (KMA) notifies the above-mentioned parameters, except for the Rmax and background state. The contribution of background wind and pressure is not very significant; however, Rmax is essential for calculating typhoon winds. Therefore, the optimized Rmax for the typhoons over the past five years was estimated at each time step compared with the in situ wind observation record. After that, a fifth-order polynomial fitting was performed between the estimated Rmax and the radius of strong wind (RSW; >15 m/s) provided by the KMA. Finally, the Rmax was calculated from the RSW via the empirical equation, and the horizontal fields of typhoon Hinnamnor (2211) were reproduced using a parametric model. Furthermore, the ocean storm surge height was adequately simulated in the surge model.

Jeong, S.H.; Khim, B.K..; Jo, Y.H., Kim, B.O., Lee, S.H. and Park, K.S., 2016. Shoreline change rate of the barrier islands in Nakdong River Estuary over the southern part of Korea. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 248–252. Coconut Creek (Florida), ISSN 0749-0208. Shoreline data of the barrier islands in the Nakdong River Estuary in Korea for the last three decades were assembled using six sets of aerial photographs and seven sets of satellite images. Canny Algorithm was applied to untreated data in order to obtain a wet-dry boundary as a proxy shoreline. Digital Shoreline Analysis System (DSAS 4.0) was used to estimate the rate of shoreline changes in terms of three statistical variables; End Point Rate (EPR), Linear Regression Rate (LRR) and Least Median of Squares (LMS). Based on Digital Shoreline Analysis, shoreline cha...

This study aims to comprehensively evaluate the Coastal-KOOS Level 2 model’s ability to predict near-surface currents throughout the Northwest Pacific, using an extensive dataset of 153 surface drifters deployed since 2020. These drifters were released in diverse oceanographic settings, including the Yellow Sea, East China Sea, and East/Japan Sea, which feature strong tidal forcing, boundary currents (e.g., the Kuroshio).We utilized drifter trajectories to derive Eulerian velocities, which were then compared with model outputs. To further validate the drifter-derived velocities, we contrasted them with in situ measurements from multiple fixed observation sites in offshore Korean waters. We also examined the influence of Stokes drift and direct wind forcing by attempting to remove these components from the drifter velocities; however, the corrections had negligible impact on most trajectories, likely because the majority of each drifter’s body remained submerged, thereby limiting its wind exposure.Forecast accuracy was quantified using several statistical metrics, including root-mean-square error (RMSE), correlation coefficient, and complex correlation (separating magnitude and directional agreement). The results indicate that Coastal-KOOS exhibits robust performance in regions dominated by tidal currents, such as parts of the Yellow Sea, where the model’s operational focus aligns well with actual conditions. In contrast, performance degrades in areas strongly influenced by the Kuroshio and in the East/Japan Sea, likely due to strong eddies and persistent warm currents that are not fully resolved by the current model configuration. In the Korea Strait and along the Chinese coast, the model generally captures flow directions more reliably than current magnitudes, underscoring the importance of regional calibration and higher-resolution modeling.Future improvements will focus on integrating additional observational data, including temperature and sea surface height, to better capture the complex dynamics of offshore regions. These findings underscore the importance of regional calibration and high-resolution modeling in refining operational ocean predictions. Ultimately, a strengthened Coastal-KOOS framework will enhance the accuracy of search-and-rescue operations, environmental monitoring, and disaster response in waters around the Korean peninsula.