Myung-Seok Kim

A review: methane capture by nanoporous carbon materials for automobiles

【Global warming is considered one of the great challenges of the twenty-first century. In order to reduce the ever-increasing amount of methane (CH 4 ) released into the atmosphere, and thus its impact on global climate change, CH 4 storage technologies are attracting significant research interest. CH 4 storage processes are attracting technological interest, and methane is being applied as an alternative fuel for vehicles. CH 4 storage involves many technologies, among which, adsorption processes such as processes using porous adsorbents are regarded as an important green and economic technology. It is very important to develop highly efficient adsorbents to realize techno-economic systems for CH 4 adsorption and storage. In this review, we summarize the nanomaterials being used for CH 4 adsorption, which are divided into non-carbonaceous (e.g., zeolites, metal-organic frameworks, and porous polymers) and carbonaceous materials (e.g., activated carbons, ordered porous carbons, and activated carbon fibers), with a focus on recent research.】

Atmospheric Analysis on the Meteo-tsunami Case Occurred on 31 March 2007 at the Yellow Sea of South Korea

A meteo-tsunami occurred along the coastline of South Korea on 31 March 2007, with an estimated maximum amplitude of 240 cm in Yeonggwang (YG). In this study, we investigated the synoptic weather systems around the Yellow sea including the Bohai Bay and Shandong Peninsula using a weather research and forecast model and weather charts of the surface pressure level, upper pressure level and auxiliary analysis. We found that 4-lows passed through the Yellow sea from the Shandung Peninsula to Korea during 5 days. Moreover, the passage of the cold front and the locally heavy rain with a sudden pressure change may make the resonance response in the near-shore and ocean with a regular time-lag. The sea-level pressure disturbance and absolute vorticity in 500 hPa projected over the Yellow sea was propagated with a similar velocity to the coastline of South Korea at the time that meteo-tsunami occurred.

Propagation of abnormal waves on 25 April 2008 at the West Coast of South Korea

ABSTRACT Kim, M.S. and Woo, S.B., Eom, H.M., 2013. Propagation of abnormal wave on 25 April 2008 at the West Coast of South Korea On 31 March 2007, abnormal waves suddenly hit the West Coast of South Korea, causing heavy casualties and huge economic loss. Since the cause of wave generation is unknown, we aim to study the direction of wave propagation by investigating the abnormal wave signal recorded in the tidal stations. To determine the propagation direction of abnormal waves, we analyzed tidal level observation data at 1-min intervals, provided by the Korea Hydrographic and Oceanographic Administration (KHOA). To remove tidal components, wavelet decomposition, which filters wave periods ranging from 2 to 60 min, was performed. If the daily maximum amplitude exceeding 95% confidence interval of the total daily maximum amplitudes appeared simultaneously at more than three tidal stations, the day was defined as the day when abnormal waves occurred. Because of nonstationarity and localized peak in the time domain, wavelet analysis can be suitable for analyzing the power spectrum and wave period of abnormal waves. The time when maximum total power spectrum of the decomposed time series appears for the first time is considered the arrival time of the abnormal wave. The distance of crest line propagated by the abnormal wave was calculated by considering the arrival time difference between stations and long wave speed. The abnormal wave is assumed to propagate along a tangent to a circle with radius equal to the distance which the abnormal waves moved. Based on these considerations, we found that the propagation direction of the abnormal waves on 31 March 2007 was from the northwestern corner of the West Sea to the West Coast of South Korea. Similarly, abnormal waves that occurred on 25 April 2008 were propagated from the northwestern corner of the West Sea to the east–southeast.

Numerical Weather Prediction for Mitigating the Fatal Loss by the Meteo-tsunami Incidence on the West Coast of Korean Peninsula

ABSTRACT Kim, H.; Kim, M.-S.; Kim, Y.-K.; Yoo, S.-H., and Lee, H.-J., 2017. Numerical weather prediction for mitigating the fatal loss by the meteo-tsunami incidence on the west coast of Korean Peninsula. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 119–123. Coconut Creek (Florida), ISSN 0749-0208. The west coast of Korean Peninsula is an area where casualties and property damages by meteo-tsunamis from the Yellow Sea have been reported. A case in point is the event with an estimated maximum amplitude of 240 cm in Yeonggwang (YG) on 31 March 2007. Many studies have been carried out since then in Korea. These researches focused primarily on the oceanographic aspects (e.g., the resonance between the atmosphere and ocean). They wanted to calculate the resonance effects by the propagation velocity and direction of meteo-tsunami. On the other hand, there were no sufficient atmospheric observation data on the sea, and it was inadequate to explain the various interactions between the atmosphere and ocean. Therefore, the weather research and forecast (WRF) model was used to predict the various detailed meteorological factors (e.g., air pressure, wind vector) on the open sea. This was performed on representative meteo-tsunami events induced by four synoptic weather types. As a result, the numerical weather model, WRF, projected various gridded atmospheric information on the Yellow Sea, and the main atmospheric forcing (e.g., pressure jump line, high pressure system) of the four meteo-tsunami events could be indicated. The numerical weather modeling showed the potential to predict the coastal disaster caused by the meteo-tsunami.

Determination of Accurate Arrival Time of Meteotsunami Event in Yellow Sea

ABSTRACT Kim, M.-S.; Kim, H.; Kim, Y.-K.; Yoo, S.-H.; Eom, H.-M., and Woo, S.-B., 2017. Determination of accurate arrival time of meteotsunami event in Yellow Sea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 149–153. Coconut Creek (Florida), ISSN 0749-0208. According to a recent study by the Korean Meteorological Administration (KMA), unforeseen losses to property and human lives along the west coast of Korea in March 2007 were caused by meteotsunamis that originated at Shandong, which is located in eastern China. The determination of the arrival time of meteotsunamis in Yellow Sea is very important to protect human life and limit economic losses in coastal areas, because the analysis of meteotsunami propagation is primarily dependent on the method of arrival time. In this study, the meteotsunami event of March 29–31, 2007, the most powerful meteotsunami event reported in the Yellow Sea, was selected to find the optimal method of calculating the meteotsunami arrival time. It is difficult to estimate the arrival time of a meteotsunami that is commonly observed as a non-stationary signal in a time series without any specific criterion. To find a quantitative and reasonable method of estimating the arrival time, the propagation direction of the meteotsunami was analyzed using the arrival time at each tidal station derived from the absolute and relative threshold of the sea level oscillations in the meteotsunami frequency bands. The results indicated that the meteotsunami propagation derived using the relative threshold which defines the arrival time as the time when the amplitude of the sea level oscillation exceeds 3 standard deviations was more similar to the propagation pattern of the high rain rate field than other thresholds.

Study of the Residual Flow and Salinity during the Spring and Neap Tides at the Seokmo Channel, South Korea

ABSTRACT Yoon, B.I.; Choi, N.Y.; Gu, B.H.; Kim, J.W.; Song, J.I.; Lim, C.W.; Kim, M.S., and Woo, S.B., 2016. Study of the residual flow and salinity during the spring and neap tides at the Seokmo channels, South 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. 1422 - 1426. Coconut Creek (Florida), ISSN 0749-0208. The Seokmo (SM) channel of Gyeonggi Bay, located in the South Korea, exhibits unique and complex estuarine circulation characteristics. This study analyzed the salinity observations, and the cross-sectional variations in the residual current and strengths of stratification by tidal current, along two cross-channels transects, during the 13-hour periods of the spring and neap tides, respectively. The cross-sectional averaged residual velocity, at the northern entrance of the SM channel, showed a seaward directional flow of 0.05 m/s during the neap tide, and 0.21 m/s during spring tide. At the southern entrance, the residual current showed two-layer circulation with a landward flow in the bottom layer, and a seaward flow in the surface layer. The spatial characteristics of the landward residual current, at the southern entrance are different for the eastern and western sides of the channel, depending on the spring and neap tidal cycles. The variation in the location of the observed landward residual current, caused by the changes in spring and neap tidal cycles, and the correlation between this variation and the stratification, were analyzed using the Richardson number. At the northern and southern end of the SM channel, a landward residual current appeared in the location that Richardson number was large. These results suggested that the cross-sectional residual current pattern, at the SM channel, changes depending on freshwater and topographical influences, and is sensitive to tidal changes, such as changes in the spring and neap tidal cycles.

Double Resonance Effect at Daeheuksando Port Caused by Air Pressure Disturbances in Yellow Sea on 31 March 2007

ABSTRACT Kim, M.S.; Kim, H.S.; Kim, Y.K.; Gu, B.H.; Lee, H.J., and Woo, S.B., 2016. Double resonance effect at Daeheuksando Port caused by air pressure disturbances in Yellow Sea on 31 March 2007. 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. 1142 - 1146. Coconut Creek (Florida), ISSN 0749-0208. We found that an internal resonance, combined with other topographic effects, following an external resonance could significantly amplify insignificant sea-level oscillations in the open sea to wave heights of several meters in a coastal area. Sudden sea-level oscillations characterized by high frequencies (0.0042–0.5 min−1) and a maximum wave height of about 1 m were observed at Daeheaksando Port (DP) on 31 March 2007. These sea-level oscillations, which caused heavy casualties and large economic loss, were also detected along the west coast of South Korea. Particularly, at DP, there were sea-level oscillations that had significant power spectrum in a specific period band. When the maximum power spectrum of the sea-level oscillations increased rapidly, the period of the maximum power spectrum converged toward the fundamental period of the port. However magnitude of the air pressure disturbance at DP could not make such sea-level oscillations. The resulting sea-level oscillations were likely amplified by the free waves generated by air pressure disturbances at KyukRyulbeedo (KR) and propagated to DP. The initial magnitude of the disturbances propagated from Shandong was approximately 2.5 hPa/10-min, based on results of the atmospheric model. Theoretically, a 2.5 hPa air pressure change can make sea-level oscillations of about 2.5 cm, but it made meteotsunamis in the port because of the double resonance effect on 31 March 2007.

Seasonal Characteristics and Mechanisms of Meteo-tsunamis on the West Coast of Korean Peninsula

ABSTRACT Kim, H.; Kim, M.-S.; Lee, H.-J.; Woo, S.-B., and Kim, Y.-K. 2016. Seasonal Characteristics and Mechanisms of Meteo-tsunamis on the West Coast of Korean Peninsula. 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. 1147 - 1151. Coconut Creek (Florida), ISSN 0749-0208. A meteo-tsunami is produced by atmospheric disturbances, such as pressure jumps, and the seasonal frequency changes of meteo-tsunamis might be dependent on the seasonal synoptic weather features. Therefore, an analysis of the synoptic atmospheric mechanism for the cause of meteo-tsunamis is important for predicting the meteo-tsunamis precisely and reducing the sudden damage. As the west coast of the Korean peninsula is a region with frequent meteo-tsunamis, the outcome of an analysis of the tidal level observation data at 1-min intervals shows that meteo-tsunami have occurred 92 times (3-SD(exceeding the 3 times of standard deviation): 28 times, 2-SD: 64 times) over the last 12 years (2002–2013). Meteo-tsunamis occur every season but have the greatest frequency in the spring (MAM; 53.3%) and winter (DJF; 26.1%). In particular, strong meteo-tsunamis in excess of 3-SD have occurred in spring (53.6%) and winter (28.6%). Climatologically, low pressure systems often passes through the Korean peninsula located in the mid-latitudes during spring. In this season, the potential instability of the atmosphere is increased on the Yellow sea. On contrast, the Siberian high pressure system periodically extends to the Korean peninsula during winter. This can cause atmospheric dynamic instability from the boundary between the land and sea.