• Title/Summary/Keyword: Sea disaster

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Estimate of Particulate Organic Carbon Export Flux Using $^{234}Th/^{238}U$ Disequilibrium in the Southwestern East Sea During Summer (동해 서남해역에서 여름철 $^{234}Th/^{238}U$ 비평형을 이용한 입자상 유기탄소 침강플럭스 추정)

  • Kim, Dong-Seon;Choi, Man-Sik;Oh, Hae-Young;Kim, Kyung Hee;Noh, Jae-Hoon
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.14 no.1
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    • pp.1-9
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    • 2009
  • Export fluxes of particulate organic carbon were estimated for the first time by using $^{234}Th/^{238}U$ disequilibrium in the southwestern East Sea during August 2007. They were calculated by multiplying POC/$^{234}Th_p$ ratios of sinking particles (larger than 0.7 ${\mu}m$) obtained from 150-200 m water depths to $^{234}Th$ fluxes that were estimated by integrating $^{234}Th/^{238}U$ disequilibrium from surface to 100 m water depth. Export fluxes ranged from 14 to 505 mg C $m^{-2}$ $day^{-1}$, with the highest value at station A2 and the lowest value at station D4. Primary production was well correlated with export flux, indicating that it was a major factor controlling export flux. Export flux in the East Sea was generally higher than those estimated in the open ocean and similar to or somewhat higher than those in the continental marginal seas. Export flux/primary production (EF/PP) ratios varied from 0.29 to 0.62, with an average of 0.43 and were somewhat higher in the basin area than in the coastal area. EF/PP ratio in the East Sea was rather similar to those estimated in the North Sea and Chukchi Sea, but much higher than those in the Labrador Sea, Barents Sea, and Gulf of Lions. Therefore, the East Sea is one of the major areas where a large amount of organic carbon produced in the euphotic zone sinks into the deep layer below 200 m water depth.

The Characteristics of Disaster by Track of Typhoon Affecting the Korean Peninsula (한반도 영향 태풍의 이동경로에 따른 재해 특성)

  • Ahn, Suk-Hee;Kim, Baek-Jo;Lee, Seong-Lo;Kim, Ho-Kyung
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.3
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    • pp.29-36
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    • 2008
  • The purpose of this study is to examine the characteristics of disaster associated with typhoon passed through the sea areas excluding the South Sea around the Korean Peninsula. First, Korean peninsula-affecting typhoons were divided into their track patterns of passing through the Korean West Sea and East Sea based on typhoon data from 1951 to 2006 provided by Regional Specialized Meteorological Center(RSMC)-Tokyo. Then, annual and monthly frequency and intensity of typhoon in each pattern was examined. In particular, typhoon related damages during the period of 1973 to 2006 were analyzed in each case. Results showed that since early 1970, in the West Sea case, typhoon becomes weaker without significant change in frequency, while in the East Sea case, it becomes stronger with an increasing trend. It is also found that the high amount of typhoon damage results from the submergence of houses and farmlands in the East Sea case, while it is due to the breakdown of houses, ships, roads and bridges in the West Sea case. In addition, it is revealed from the analysis of rainfall and maximum wind speed data associated with typhoon disasters that the main cause of occurring typhoon disasters seem to be qualitatively related to strong wind in the West Sea case and heavy rainfall in the East Sea case.

Assessment of Water Piling-up behind a Submerged Breakwater during Storm Events (단기 태·폭풍 기인 잠제 배후의 Piling-up 현상 평가)

  • Son, Donghwi;Yoo, Jeseon;Kim, Mujong
    • Journal of Coastal Disaster Prevention
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    • v.5 no.4
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    • pp.203-210
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    • 2018
  • It is generally known that submerged breakwaters can reduce the incoming wave energy without disturbing the beach scenery. However, a submerged breakwater is also able to cause a setup of the sea level in the protected area which is also called as water piling-up. Since the piling-up can result in longshore currents, sediment transports, and unexpected beach erosion, understanding about the piling-up process is required prior to designing the nearshore structures. In this study, the water piling-up behind a submerged breakwater is assessed in the time of storm events. For the study area, Anmok beach in Gyeonso-dong, Gangwon-do is selected. 1-year, 5-year, 10-year, and 50-year return-values were derived from Peaks-Over-Threshold(POT) method and those are applied as offshore boundary conditions for the numerical simulation. The numerical results of the piling-up were assessed with regard to the wave steepness and the height of the submerged breakwater. With increase of both significant wave height and the height of the submerged breakwater, the piling-up parameter is also increased which can lead to erosion of dry beach behind the structure.

Development of a Flood Disaster Evacuation Map Using Two-dimensional Flood Analysis and BIM Technology (2차원 침수해석과 BIM 기술을 활용한 홍수재난 대피지도 작성)

  • Jeong, Changsam
    • Journal of Korean Society of Disaster and Security
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    • v.13 no.2
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    • pp.53-63
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    • 2020
  • In this study, the two-dimensional flow analysis model Hydro_AS-2D model was used to simulate the situation of flooding in Seongsangu and Uichang-gu in Changwon in the event of rising sea levels and extreme flooding, and the results were expressed on three-dimensional topography and the optimal evacuation path was derived using BIM technology. Climate change significantly affects two factors in terms of flood damage: rising sea levels and increasing extreme rainfall ideas. The rise in sea level itself can not only have the effect of flooding coastal areas and causing flooding, but it also raises the base flood level of the stream, causing the rise of the flood level throughout the stream. In this study, the rise of sea level by climate change, the rise of sea level by storm tidal wave by typhoon, and the extreme rainfall by typhoon were set as simulated conditions. The three-dimensional spatial information of the entire basin was constructed using the information of topographical space in Changwon and the information of the river crossing in the basic plan for river refurbishment. Using BIM technology, the target area was constructed as a three-dimensional urban information model that had information such as the building's height and location of the shelter on top of the three-dimensional topographical information, and the results of the numerical model were expressed on this model and used for analysis for evacuation planning. In the event of flooding, the escape route is determined by an algorithm that sets the path to the shelter according to changes in the inundation range over time, and the set path is expressed on intuitive three-dimensional spatial information and provided to the user.

Characteristics and long term variation trend of water mass in the coastal part of East Sea, Korea (동해연안 수괴의 특성과 장기변동 추이)

  • Yoon, Yi-Yong;Jung, So-Jung;Yoon, Sang-Chul
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.10 no.1
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    • pp.59-65
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    • 2007
  • Rapid variation of coastal ecosystem in the East Sea of Korea, such as fishery resource variation and subtropical chang of bentic flora, accordong to the global warming are actually noticed. In this study we try to identify the characterics of water mass existing in this coastal area and to consider the variation of their physical and chemical properties using data of temperature, salinity and dissolved oxygen obtained by National Fisheries Research & Development Institute from 1960 to 2005. The temperature of all water mass rise during last 45 years; the rise of North Korea Cold Water temperature (about $2.33^{\circ}C$) is 1.5 times higher than that of Tsushima warm water (about $1.6^{\circ}C$), and the temperature rise of Tsushima Surface Water, directly affected by climate chang is $2.57^{\circ}C$, higher than the atmospheric temperature rise during same period, indicating that subtropical change makes progress more rapidly in the coastal marine ecosystem than in the land ecosystem. Otherwise, the salinity in the surface water decrease $0.29\%_{\circ}$ during last 45 years due to the rising trend of rainfall with atmospheric temperature. The dissolved oxygen concentration in the all water mass make a decreasing trend. Specially for the North Korea Cold Water, the dissolved oxygen concentration diminish 0.021 mg/l per year and the decrease in the East Sea Proper Water indicate a change of inner water circulation system.

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Variability of Surface Chlorophyll Concentration in the Northwest Pacific Ocean (북서태평양의 표층엽록소 변동성)

  • Park, Ji-Soo;Suk, Moon-Sik;Yoon, Suk;Yoo, Sin-Jae
    • Ocean and Polar Research
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    • v.30 no.3
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    • pp.277-287
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    • 2008
  • We collected information on seasonal and interannual variability of surface chlorophyll a concentration between 1997-2007 from the Northwest Pacific Ocean. Satellite data were used to acquire chlorophyll a and sea surface temperature from six regions: East Sea/Ulleung Basin, East China Sea, Philippin Sea, Warm Pool region, Warm Pool North region, and Warm Pool East region. Mixed layer depth (MLD) was calculated from temperature profiles of ARGO floats data in four of the six regions during 2002-2007. In the East Sea/Ulleung Basin, seasonal variability of chlorophyll a concentration was attributed to seasonal change of MLD, while there was no significant relationship between chlorophyll a concentration and MLD in the Warm Pool region. Interannual anomaly in sea surface temperature were similar among the East Sea, East China Sea, Philippin Sea, and Warm Pool North region. The anomaly pattern was reversed in the Warm Pool East region. However, the anomaly pattern in the Warm Pool region was intermediate of the two patterns. In relation to chlorophyll a, there was a reversed interannual anomaly pattern between Warm Pool North and Warm Pool East, while the anomaly pattern in the Warm Pool region was similar to that of Warm Pool North except for the El $Ni\tilde{n}o$ years (1997/1998, 2002/2003, 2006/2007). However, there was no distinct relationship among other seas. Interestingly, in the Warm Pool and Warm Pool East regions, sea surface temperature showed a pronounced inverse pattern with chlorophyll a. This indicates a strong interrelationship among sea surface temperature-MLD-chlorophyll a in the regions. In the Warm Pool and Warm Pool East, zonal distribution of chlorophyll a concentration within the past 10 years has shown a good relationship with sea surface temperature which reflects ENSO variability.

A Technical Approach to Post-Traumatic Stress Disorder of the Sewol Ferry Victims' Parents (세월호 참사 희생자 부모들의 심리적 외상에 관한 기술적 접근)

  • Park, Gi-Muk
    • The Journal of the Korea Contents Association
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    • v.15 no.9
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    • pp.134-145
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    • 2015
  • It has been 1 year since Sewol Ferry disaster occurred in the Gwanmaedo sea of Jindo, Jeollanamdo, on Apr. 16, 2014. The Sewol Ferry Disaster which took 304 lives and had some victims still missed has become the largest tragic accident in Korea since 2010. Although one year has passed since the disaster, there is no psychological communication research on the trauma of the victims' families. This study first investigated the actual state of the Sewol Ferry victims' parents suffering from post-traumatic stress disorder (PTSD) after their losses of children by the disaster. This study revealed that the victims' families suffer from physical and psychological the PTSD but neglect treatment. The PTSD still influences their daily life. It was observed that the victims' families have a lot of difficulties with interpersonal relationship, relationship with co-workers, residence, values, and other kinds of daily life. Given that the victims' families have a great deal of PTSD after the disaster, the academic circle needs to make discussions of the issue actively in order to heal the pains of the Sewol Ferry victims' families who are unattended in our society.

A Numerical Study on the Formation Mechanism of a Mesoscale Low during East-Asia Winter Monsoon

  • Koo, Hyun-Suk;Kim, Hae-Dong;Kang, Sung-Dae;Shin, Dong-Wook
    • Journal of the Korean earth science society
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    • v.28 no.5
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    • pp.613-619
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    • 2007
  • Mesoscale low is often observed over the downstream region of the East Sea (or, northwest coast off the Japan Islands) during East-Asia winter monsoon. The low system causes a heavy snowfall at the region. A series of numerical experiments were conducted with the aid of a regional model (MM5 ver. 3.5) to examine the formation mechanism of the mesoscale low. The following results were obtained: 1) A well-developed mesoscale low was simulated by the regional model under real topography, NCEP reanalysis, and OISST; 2) The mesoscale low was simulated under a zonally averaged SST without topography. This implies that the meridional gradient of SST is the main factor in the formation of a mesoscale low; 3) A thermal contrast ($>10^{\circ}C$) of land-sea and topography-induced disturbance served as the second important factor for the formation; 4) Paektu Mountain caused the surface wind to decelerate downstream, which created a more favorable environment for thermodynamic modification than that was found in a flat topography; and 5) The types of cumulus parameterizations did not affect the development of the mesoscale low.

Air Quality Changes in a Museum Damaged by a Tsunami - Whale and Sea Museum, Iwate, Japan -

  • MATSUI, Toshiya;KAWASAKI, Emi;Huttmann, Imme
    • Journal of Conservation Science
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    • v.35 no.1
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    • pp.51-60
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    • 2019
  • This paper provides quantitative data that describes the evolution of the air quality in the Whale and Sea Museum, located in the Iwate prefecture, collected after the 2011 Great East Japan Earthquake and tsunami. The museum was damaged significantly by the disaster, and restoration works continued for over six years. The air quality in the temporary storage facility and museum was monitored during the rehabilitation process. Evaluation of air quality is carried out by gas chromatography- mass spectrometry, ion chromatography and high-performance liquid chromatography. The results showed that the characteristics of the chemical components differed depending on the measurement locations inside the building. The museum atmosphere tended to be alkaline as the airtightness increased because of the maintenance works at the entrance. It was also determined that it was necessary to study the intake/exhaust routes and to clean them according to the contamination degree. In Japan, there are recommended museum air quality standards for acetic acid, formic acid, alkali, and aldehydes. The results indicated that these standards should not be used as a reference for damaged museums. Furthermore, at the temporary storage facilities for to store the collections during the rehabilitation of the museum, solvents such as ethyl benzene, toluene, and xylene are initially abundant, although they can be reduced by ventilation, while other components such as 2E1H was confirmed in this case are likely to remain.