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ABSTRACT Lee, J.H. and Kim, T.R., 2018. Study of High Waves caused by Slanting-fetch Effects along the Coast. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 831–835. Coconut Creek (Florida), ISSN 0749-0208. Design wave height estimation for the ports and coastal structures are mainly based on the waves from offshore wind which have long fetches enough to develop high waves. The waves generated by short fetched land wind are usually neglected because they are thought to be small and short period waves. However, in case of land wind oblique to the long coast line with short fetch, unexpected long period high waves are developed along the coast by slanting-fetch effects. These high waves can damage human lives as well as coastal structures, but are difficult to predict using offshore wave measurement system. Therefore, it is important to understand the characteristics of waves by slantingfetch and prepare countermeasures against them. This paper analyzes observed wind and wave data in the East Sea, on Feb. 6–8th and Dec. 12–14th in 2013, when waves were developed by slanting-fetch effects near the coast. During these periods, strong northwest wind of over 15 m/sec lasted more than 24 hours, but southwestward waves with significant wave height of over 1.5 m and peak period of over 10 sec were observed at Hupo Harbor in spite of land wind with short fetch. Unstructured WAVEWATCH III model is executed to simulate the waves generated by slanting-fetch effects and RDAPS/UM wind data with 12 km resolution provided by NCMS/KMA are used as forcing input data. The numerical wave model results at Hupo Harbor show relatively good agreement with in-situ measurement data explaining high waves with long period by slanting-fetch effects, and both observed and simulated wave directional spectrum at Hupo Harbor show strong energy in long period and southwestward direction. [ABSTRACT FROM AUTHOR]

ABSTRACT Kim, H.; Son, Y.B.; Jeong, J.-Y., and Jo, Y.-H., 2018. Comparison of Internal Waves in Various Ocean Fields around the Korean Peninsula. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 466–470. Coconut Creek (Florida), ISSN 0749-0208. The sea surrounding the Korean Peninsula is roughly divided into the western part (the Yellow Sea (YS) and the South Sea (SS); shallow inland sea) and the eastern part (the East Sea (ES); drastically deep). While internal wave (IW) studies have been mainly localized because of the complicated environmental conditions around the Korean Peninsula, this study determined the differences of the IWs in various ocean fields for over three years (2013–2015). First, satellite measurements with high spatial and temporal resolutions from Landsat 8 and the Geostationary Ocean Color Imager (GOCI) were used. The curvature analysis was used to define and compare the shapes of the objective factors of the IWs, such as sizes, ovalities, and maximum wavelengths. In the YS, IWs appeared at a densely spaced interval compared with the ES and the maximum wavelength of the packet was nonlinearly increased with depth, and that of the YS (1.1 km) was about 10 times larger than and ES (10.6 km). In addition, the standard deviations of the wavelengths in a packet, which can determine the irregularity of the within-packet spacings from front to rear; were 0.2 and 1.4 for the YS and ES, respectively. Second, the ocean temperature and salinity data from HYCOM and Korteweg-de Vries equation were used to calculate the theoretical phase speed of IWs. Typically, the IW phase speed increased nonlinearly with the water depth; and the mean value was approximately 0.1–0.7 m/s and 0.9–1.7 m/s for the YS and ES, respectively. [ABSTRACT FROM AUTHOR]

Extensive wave monitoring was carried out over nine consecutive years at nine different locations along the east coast of Korea in order to examine the overall wave statistics and to investigate the generation and propagation mechanism of occasional high waves in this region. This type of long-term wave observation at multiple stations has never been performed on the Korean east coast. Appearances of high waves, defined by criteria of Hs=3 m and Ts=9 s at any of the nine stations within a single day accounted for approximately 5% of the total data. These high waves mostly occurred in winter under the influence of strongly developed winter storms over the East Sea. Among these high wave events, three representative cases were subjected to a further intensive analysis by using the corresponding wave data together with meteorological data at that time. Based on such a synthetic analysis, it was possible to understand details regarding the general patterns in the development of low pressures and subsequent formation of strong wind fields around the coastal zone, which eventually affected the characteristics of the high waves that were observed. [ABSTRACT FROM AUTHOR]

In this study the effect of underwater topography of the East Sea on the propagation of tsunamis towards the Korean Peninsula is investigated using the dispersion-correction finite difference numerical model. A series of numerical simulations are conducted for three tsunami events including the 1964 Niigata Tsunami, the 1983 Central East Sea Tsunami and the 1993 Hokkaido South-West Sea Tsunami for the cases of examining the individual or combined influence of underwater topographic features. These include the Yamato Rise, a submerged ridge connecting Yamato Rise and the Shimane Peninsula of Japan, and K-shaped submerged ridges emerging from the east coast of Korea towards the East Sea. In particular, in order to evaluate quantitatively the effects of underwater topography on the propagation of tsunamis, a new concept of energy discharge per unit width is introduced. Using this concept, the quantitative analyses of energy propagation during tsunami events are performed. The analyses show that the underwater topographies including the submerged rises and ridges capture the tsunami energy and transport it to coastal areas connected to those topographies. [ABSTRACT FROM AUTHOR]

Three species of the genus Paradoxostoma Fischer, 1855 are reported from the South Korean East Coast: Paradoxostoma flaccidum Schornikov, 1975, P. brunneum Schornikov, 1974, and one new species, P. sokchoensis, new species. The first species was previously reported from the East Sea off the Korean peninsula, with additional Paradoxostoma as part of a species list of an ecological study carried out in South Korea. Paradoxostoma sokchoensis is most closely related to P. depressum Okubo, 1977 and P. assimile Okubo, 1978. Three major differences between the new species and the other two species are: 1) the presence of an unusual group of setulae on the antennule, 2) absence of seta on first segment of L6, and 3) a more slender anterior margin of the carapace. [ABSTRACT FROM AUTHOR]

Lee, H.S., 2013. Abnormal storm waves in the East Sea (Japan Sea) in April 2012 The winter East Sea, a semi-enclosed sea surrounded by Korea in the west, Japan in the east and south and Russia in the north, normally experiences rough sea conditions due to East Asian monsoon and winter storms. In April 2012, record-breaking abnormally high waves, significant wave heights of 11.21 m and 12.39 m and significant wave periods of 13.6 sec and 14.3 sec at Akita and Yamagata GPS buoy sites, respectively, were observed along the Tohoku coast in the East Sea side of Japan. It was due to a well- and fast-developed low pressure passing through the East Sea. This paper describes how a low pressure could be grown so rapidly to tropical cyclone level in this time and numerical hindcast results for future forecast and engineering purpose. With respect to the meteorological condition, it is found that strong convective motion due to latent heat and water vapor from Tsushima Warm Current together with an accompanied front increases a pressure gradient at tropopause level accelerating the low growth. In the hindcast using an atmosphere-wave modeling system, two different initial and boundary condition data, NCEP FNL and JMA GSM, are used for applicability test. The result with NCEP FNL data shows a better agreement with observations in terms of surface winds. The observed peaks of significant wave height and period by Akita and Yamagata GPS buoy are captured well in both results. It is also found that the vertical resolution of initial and boundary condition data is important in atmospheric modeling; the higher vertical resolution tends to produce a deeper storm with lower central pressure and strong convective motion. [ABSTRACT FROM AUTHOR]

Heo, K.-Y., Shim, J.-S., Kwon, J.-I., Jeong, J.-Y., Park, K.-S. and Choi, J.-W., 2013. Abnormal storm waves around the Korean Peninsula: A case study of an extratropical explosive cyclone over East Sea. On April 3, 2012, an extratropical explosive cyclone developed over East Sea, producing heavy rainfall and strong winds. This cyclone produced maximum wind speeds of up to around 21 m s−1 over the ocean around Korea. As the explosive cyclone developed rapidly from 00 UTC April 3, 2012, it began to affect the coastal areas, and abnormal storm waves were generated by the strong wind. The observed maximum wave heights and periods around Korea were 11.1 m and 9.1 s at Chilbaldo, 12.0 m and 9.1 s at Marado, and 13.7 m, and 5.8 s at Ulleungdo in the period 04-10 UTC April 3, 2012. The objectives of this study are to investigate the mechanisms and conditions favorable for the development of the explosive cyclone, and to investigate the influence of the cyclone on the abnormal storm waves. To achieve the above objectives, numerical studies are conducted using the Weather Research and Forecasting (WRF) model as an atmospheric model and the open ocean wave model WAM. The explosive cyclone is amplified by latent heat release as well as the formation of an upper-level cut-off low, which resulted in the rapid intensification of the cyclone; while surface heat fluxes had a lesser contribution to the explosion of the cyclone. In situ meteorological observation data and wave data from buoy measurements for this event are available for comparison and validation. The comparisons show that the WRF and WAM models can accurately predict the wind speed and wave height. [ABSTRACT FROM AUTHOR]

Jang, C.J.; Kim, K.H.; Jung, H.; Do, K.; Yoo, J.; Kim, Y.S., and Lim, H.S., 2020. Future changes in significant wave heights in the East/Japan Sea. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1443-1448. Coconut Creek (Florida), ISSN 0749-0208. Future changes in wave climate play a crucial role in both coastal safety by changing coastal environments including erosion and marine ecosystem mainly by modulating nutrient input through vertical mixing changes. In this study, we investigated future changes in significant wave heights (SWHs) in the East/Japan Sea by using a regional wave model forced with future winds in the mid-21 century based on the RCP4.5 scenario. The future wind field was obtained from a regional climate model (SNU-MM5) contributing to CORDEX-EA (COordinated Regional climate Downscaling EXperiment-East Asia) project. In general, the mean SWHs are projected to increase, with a seasonally contrasting pattern: a greater increase in summer than in winter. In addition to the seasonal contrast, a basin-wide difference is also noticeable: larger changes in the northern basin than in the southern basin. The 99th percentile SWHs, a measure of extreme SWHs, show a significant spatial variation, with a maximum increase near Vladivostok, where a considerable intensification of wind is projected. Our findings suggest that the projected future changes in SWHs in the East/Japan Sea can be considerably different depending on seasons and basins. [ABSTRACT FROM AUTHOR]

Park, Y.-G.; Kim, Y.H.; Seo, S.; Hwang J.H., and Ha, H.K., 2020. Environmental impact assessment of carbon storage using a CO2 bubble model. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 138–142. Coconut Creek (Florida), ISSN 0749-0208. Carbon storage in underwater geological structures is considered as a way of mitigating global climate change. One of the environmental issues related to carbon storage is the leakage of carbon dioxide from the storage. A model for tracking CO2 bubbles in the water column has been developed to assess the environmental impact of CO2 leakage from a shallow site that is under consideration in Korea. The dependences of the rising velocity and the solubility to bubble size are taken into account while assuming spherical bubbles of from 0.1 mm to 18 mm in diameter. Since the study area is a shallow water environment (∼170 m), leaked CO2 bubbles reach the surface within 20 minutes during which the local horizontal currents transport the bubbles less than 500 m. While rising to the surface, less than about 2x10-7% of leaked CO2 is dissolved into seawater. The remaining amount is released into the air. If it is assumed that 1x105 ton of CO2 is leaked as bubbles, the pH of seawater that is influenced by the CO2 bubbles at the absence of ocean currents would be lowered by less than 0.01 on the average. If the lateral dispersion of the bubbles by ocean currents is considered, the effect would be smaller. [ABSTRACT FROM AUTHOR]