한국연안방재학회학술지最新文献

{"title":"Analysis of Spatio-Temporal intensity of Sea Fog in Yellow Sea Using Visibility Data of Ocean Research Stations (ORS) and Baengnyeongdo","authors":"Gyeong-Mi Son, Chan-Su Yang, Dae-Woon Shin, Won-Jun Choi, In-Ki Kim","doi":"10.20481/kscdp.2023.10.4.157","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.4.157","url":null,"abstract":"While existing research on sea fog primarily relied on collecting data from ground observations in coastal areas, this study utilized municipal data from three Korea Ocean Research Stations (KORS) located in the Yellow Sea and Baengnyeongdo. The main objective was to analyze the strength of sea fog in specific locations within the Yellow Sea. The study employed the corrective distance as a measure of intensity and examined variations in sea fog strength according to the monthly and by time period of the study area. The research periods for each research station were as follows: Socheongcho Ocean Research Stations (SORS) from 2014 to 2022, Gageocho Ocean Research Stations (GORS) from 2014 to 2020, Ieodo Ocean Research Stations (IORS) from 2010 to 2015, and Baengnyeongdo from 2016 to 2022. In terms of season, the highest sea fog frequency in SORS and GORS were at 59% and 75% in spring, respectively. While in IORS, sea fog intensively occurred throughout the spring (46%) and summer (47%) seasons. On the other hand, in Baengnyeongdo, the sea fog frequency in summer, spring, autumn and winter were 41%, 25%, 17% and 17%, respectively. Between September and February the occurrence frequency was 19%, 8.1% and 7.3% in SORS, GORS and IORS, respectively which tends to decrease as it descends South of the Yellow Sea. In SORS, sea fog frequency with 0.2 km (strength 2) visibility was 49% while in the case of GORS and IORS it was 15% and 22%, respectively. Besides, the frequency of sea fog which visibility was between 0.2 and 0.5 km (strength 1) was 59% and 56% in GORS and IORS, respectively. In terms of frequency by time period, SORS and GORS showed a normalization maximum of 01 at 01:00 KST where IORS showed 02. Sea fog was not seen at 12:00 in SORS, at 13-17:00 in GORS and at 19-20:00 in IORS. In the future, we will analyze the spatial distribution of sea fog occurring in the Yellow Sea after sea fog verification using satellite images.","PeriodicalId":475408,"journal":{"name":"한국연안방재학회학술지","volume":"18 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136069682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a Marine Radioactivity Expert System based on the Extended Marine Food Web: Experiments with Initial Bottom Contamination","authors":"Haejin Kim, Hanna Kim, Mee Kyung Kim, Kyeong Ok Kim","doi":"10.20481/kscdp.2023.10.4.149","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.4.149","url":null,"abstract":"An extended version of an expert system was developed as an effort to provide technical support to decision makers for the initial prompt assessment of environmental impacts of marine radioactivity, considering both pelagic and benthic marine food webs. The preliminary version of this system was firstly developed to determine the transfer of radionuclides through a pelagic marine food web (Kim et al, 2020). This system's approach was similar to the Cornell Mixing Zone Expert System (CORMIX) developed by Jirka (1995), as it used idealized settings for the physical/hydrodynamic coastal conditions. Existing or extended systems were executed by taking into account different kinds of radioactivity sources. The initial contamination of bottom sediment is considered in the present study, while the direct discharge to the coastal ocean from the nuclear power plant was considered in the early study. Assuming initial contamination, sensitivity experiments of temporal ¹³⁷Cs variations without/with horizontal advection and diffusion (EXP-WOHAD and EXP-WHAD, respectively) were conducted. In EXP-WOHAD, a total of six test cases were constructed, considering a range of vertical diffusion coefficients and sediment fluxes at the water-sea bed interface. The EXP-WHAD experiments were classified into two categories with six cases each, considering the horizontal diffusion and advection processes. The EXP-WOHAD results show that the vertical diffusion processes in the bottom sediment result in the exponential decay of the ¹³⁷Cs concentrations in the top sediment layer through upward and downward diffusive fluxes, producing pulse-like time variations in ¹³⁷Cs in the water column and the middle sediment layer. These sediment fluxes affect the peak height and its occurrence time in the water column and the middle sediment layer. From EXP-WHAD, it has been confirmed that part of ¹³⁷Cs diffused into the water column experiences horizontal dispersion and thereafter deposition to the bottom sediment. It is noted that due to the limited diffusion to the water column, the ¹³⁷Cs concentrations in benthic organisms are larger than those in pelagic organisms.","PeriodicalId":475408,"journal":{"name":"한국연안방재학회학술지","volume":"160 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136069338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Experimental Study on the Correlation Analysis between the Settling Velocity and Shape Factor of Sand","authors":"Jong Hwan An, Su-Hyun Yang, Kyu-Nam Hwang","doi":"10.20481/kscdp.2023.10.4.133","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.4.133","url":null,"abstract":"In this study, we developed a technology that allows for easy and rapid measurement of the shape factor and settling velocity of sand particles. As a result of the shape characteristic analysis based on image analysis using sand samples collected from Kkotji Beach, the shape factor (aspect ratio) of sand at Kkotji Beach is about 0.75, and the equivalent diameter was almost similar to the mean diameter calculated by sieve analysis. Also, a new apparatus was developed to calculate the settling velocity by improving the existing settling column, and the settling velocity was determined by measuring the cumulative weight. The new apparatus rapidly measured the settling velocity of sand particles falling with a time delay, and it was observed that the settling velocity increased with an increase in particle size. The measured results of the shape factor and settling velocity were compared with previous studies, but they were found to be some different. These differences may be due to the fact that factors influencing settling velocity, such as density, fluid characteristics, etc., are not reflected, but only particle size and shape factor were considered. However, overall, relatively valid values were derived within the range presented in previous studies.","PeriodicalId":475408,"journal":{"name":"한국연안방재학회학술지","volume":"0 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136069631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the Erosional Properties of Muddy Sediments: Asan Bay Case Study","authors":"Ngoran Senan Kiniben, Jong Hwan An, Kyu-Nam Hwang","doi":"10.20481/kscdp.2023.10.4.141","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.4.141","url":null,"abstract":"The study's outcomes reveal that both the critical shear stress needed to initiate erosion and the sediment erosion rate are influenced by various parameters, including the bulk density of sediment and bed shear stress. This comprehensive analysis underscores the vital role that these parameters play in determining sediment erosion characteristics. The presented research contributes to the understanding of erosional behaviors of muddy sediments and their implications. The findings emphasize the importance of comprehending such properties, especially in designing effective erosion control structures and managing water bodies prone to erosion.","PeriodicalId":475408,"journal":{"name":"한국연안방재학회학술지","volume":"63 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136070034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}