The threat of sea level rise to the heavily populated Korean Peninsula, which contains around 15,000 km of coastline bordering open sea margins, has profound and far reaching implications. This study updates and extends previous detailed studies with the addition of a further 2 years of data to the end of 2019, providing renewed robustness to the identification of emerging threats associated with sea level rise within the warming sea margins around the Korean Peninsula. The study analyzes tide gauge records and satellite altimetry around the Republic of Korea using enhanced time series analysis techniques to detect coastal vertical land motion and current rates of rise in mean sea level to augment planning, design and risk management activities. Despite fluctuations over time at each site, the highest “relative” mean sea level at each of the seven longest tide gauge records occurs in 2019, with weak evidence of an acceleration in the increase in mean sea level around the Republic of Korea. Trends in sea surface height from satellite altimetry across this region note two discreet areas east and west of the Korean Peninsula around 37.5° N (around Ulleungdo Island and in the Gyeonggi Bay region of the Yellow Sea), where rates of rise are well above the global average trend.

This study investigates the interannual variations in regional mean sea levels (MSLs) of the northeast Asian marginal seas (NEAMS) during August, focusing on the role of typhoon activity from 1993 to 2019. The NEAMS are connected to the Pacific through the East China Sea (ECS) and narrow, shallow straits in the east, where inflow from the southern boundary (ECS), unless balanced by eastern outflow, leads to significant convergence or divergence, as well as subsequent changes in regional MSLs. Satellite altimetry and tide-gauge data reveal that typhoon-induced Ekman transport plays a key role in MSL variability, with increased inflow raising MSLs during active typhoon seasons. In contrast, weak typhoon activity reduces inflow, resulting in lower MSLs. This study’s findings have significant implications for coastal management, as the projected changes in tropical cyclone frequency and intensity due to climate change could exacerbate sea level rise and flooding risks. Coastal communities in the NEAMS region will need to prioritize enhanced flood defenses, early warning systems, and adaptive land use strategies to mitigate these risks. This is the first study to link typhoon frequency directly to NEAMS MSL variability, highlighting the critical role of wind-driven processes in regional sea level changes.

The friction factor in open channel flow is considered to increase proportionally with wall roughness compared to that of pipe flow because of undulation at the free surface. The undulation is considered to be driven from the bottom and side walls. The increment factor associated with free surface undulation, shape distortion, and meandering is related to the Manning coefficient, and the incremented friction factor is substituted into the friction factor of circular pipe smooth (stretching) turbulent flow so as to yield the friction factor for open channel flow. The new equation for friction factor or mean velocity provides similar results to the Manning equation and the Ganguillet-Kutter (GK) equation for small streams. However, it is found that the Manning equation results in larger values of mean velocity in wide rivers compared with the GK equation and the new logarithmic equation based on the concept termed as "smooth turbulent,'' which appears inappropriate in describing the turbulent flow mechanism. Smooth turbulent may have to be denoted as "stretching turbulent'' because of stretching of the velocity profile as the Reynolds number increases. Based on the comparison results with the other two empirical equations, the new logarithmic equation could be suitably adopted in open channel flows.

The Ieodo Ocean Research Station (IORS) has been a critical site for collecting oceanic and atmospheric data over 19 years (2005-2023). This study analyzes key parameters including tide, wave, water temperature, salinity, wind, air temperature, etc. While these datasets have provided valuable insights into regional climatic and oceanographic phenomena, significant incorrect data were identified, particularly in the records from 2015 to 2019. Issues such as overlapping data spanning multiple years, non-chronological ordering, and discrepancies in decimal precision were detected likely due to inadequate data handling during the adjustment process in programs like Excel. These errors, which persisted for years without detection or correction, highlight a lack of responsibility and verification among both government and private sector employees involved in data management. Given the substantial investment of government resources in the IORS, the continuous presence of incorrect data on official platforms raises concerns that extend beyond the responsible parties to the broader scientific and public communities. To prevent future occurrences, the study emphasized the need for stringent data management practices and ongoing accuracy in data handling, ensuring that the IORS continues to serve as a reliable resource for oceanographic research in Korea and globally.

Lim, H.; Miles, T.; Glenn, S.; Kim, D.; Kim, M.; Shim, J.; Chun, I., and Hwang, K., 2020. Rapid ocean destratification by typhoon Soulik over the highly stratified waters of west Jeju Island, Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1480–1484. Coconut Creek (Florida), ISSN 0749-0208.Global warming is affecting ocean disasters by intensifying typhoons, which present a threat to people living in coastal cities. The increase of intensity has been observed in the typhoons approaching the southwestern Korean Peninsula; this increase can be attributed to the increasing water temperature and strong stratification of the Yellow Sea in summer. Typhoon Soulik was formed on August 16, 2018 in the western North Pacific and tracked northwestward toward the Yellow Sea, slowing down as it moved towards the highly stratified coastal waters of western Jeju Island on August 23. However, its intensity rapidly decreased from a typhoon to a tropical storm before it landed on the southwestern Korean Peninsula. Typhoon Soulik was observed by the Korea Institute of Ocean Science and Technology's (KIOST) Ieodo Ocean Research Station (IORS), the Korea Hydrographic and Oceanographic Agency's (KHOA) Moslpo tidal station, and an underwater glider deployed by KIOST and Rutgers University as a part of the Joint Program Agreement (JPA) by the Korean Ministry of Oceans and Fisheries (MOF) and National Oceanic and Atmospheric Administration (NOAA). The glider was deployed over the Yellow Sea Trough, west of Jeju Island near IORS, from August 15 to 25, 2018; during this time, the eye of typhoon Soulik travelled within 26 km of the glider track on August 23 at 04:37 Korea Standard Time (KST). The glider also observed a rapid ocean cooling where the surface temperature dropped from 27.5°C to 16.5°C while the bottom temperature increased from 11°C to 14°C, and the pycnocline deepened from 30 to 60 m. The rapid ocean mixing coincided with a tidal transition followed by several hours of sustained winds and waves with limited mixing and cooling. It is suggested that this rapid ocean destratification might reduce the intensity of typhoon Soulik before landfall.

To cope with the water pollution problem, the Dongsam seawater stream was newly renovated in 2022. For this maintenance, government constructed various facilities including electric swing sluice gates at both ends to enhance seawater exchange performance. In this regard, this study tries to quantify water velocity increment and water quality of the stream and offer suggestions for effective management. To achieve this goal, the authors performed literature review on water quality improvement, GPS buoy tracking experiments, long-term current measurement (Aquadopp), water quality monitoring, analysis of daily log data of the sluice gate. The results of this study indicate that operation of bi-directional swing sluice gates with maximum tidal range conditions can strengthen current intensity that contributes to enhance water quality of Dongsam seawater stream.