• Title/Summary/Keyword: Sea-level rising

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Trend of Sea Level Change Along the Coast of Korean Peninsula

  • An Byoung Woong;Kang Hyo Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.6
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    • pp.803-808
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    • 1999
  • Trend of sea level change has been analysed by using the tidal data gathered at the 12 tide stations along the coast of Korean peninsula. Analysis and prediction of the sea level change were performed by Principal Component Analysis (PCA). For the period of 20 years from 1976 to 1995, the trend generally shows a rising pattern such as 0.22 cm/yr, 0.29 cm/yr, and 0.59 cm/yr along the eastern, southern, and western coast of Korea, respectively. On the average the sea level around the Korean peninsula seems to be rising at a rate of 0.37 cm/yr. Adopting the average rate to the sea level prediction model proposed by EPA (Titus and Narrayanan, 1995), the sea level may be approximately 50$\~$60 cm higher than the present sea level by the end of the next century.

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Holocene Sea Level Changes in the Eastern Yellow Sea: A Brief Review using Proxy Records and Measurement Data (황해 동부 연안의 홀로세 해수면 변화: 대리기록과 관측자료를 통한 재검토)

  • Lee, Eunil;Chang, Tae Soo
    • Journal of the Korean earth science society
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    • v.36 no.6
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    • pp.520-532
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    • 2015
  • In order to understand the Holocene sea level changes in the eastern Yellow Sea, the west coast of Korea, and to compare the rates of sea level rise in each period of time, the geological proxy records for pre-instrumental era and measurement data for the present day were combined and analysed. The sea level in the Yellow Sea rose fast with a rate of about 10 mm/yr during the early Holocene, and decelerated down to 1 mm/yr since the mid to late Holocene. The rising rates of sea level in the 20th century were slightly higher than those in the late Holocene. The present-day rates of sea level rise, known as the 'rapid' rise, are in fact much lower or similar, compared to the early to mid Holocene sea levels in the study area. Recent tide-gauge data show that sea level rise in the eastern Yellow Sea has been accelerating toward the 21st century. These rising trends coincide well with global rising patterns in sea level. Additionally, the present-day rising trends of sea level in this study are correlated with increased rates of carbon dioxide concentrations and sea surface temperatures, further indicating a signal to global warming associated with the human effect. Thus, the sea level changes induced by current global warming observed in the eastern Yellow Sea and world's oceans can be considered as 'Anthropocene' sea level changes. The changes in sea level are based on instrumental measurements such as tide-gauges and satellite altimetry, meaning the instrumental era. The Holocene changes in sea level can thus be reconstructed from geological proxy records, whereas the Anthropocene sea-level changes can be solely based on instrumental measurements.

Relations between Variation of Sea Surface Temperatures in the South Sea of Korea and Intensity of Typhoons (남해 해수면온도 변화와 태풍 세기와의 관계)

  • Seol, Dong-Il
    • Journal of Navigation and Port Research
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    • v.32 no.5
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    • pp.403-407
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    • 2008
  • Relations between variation of SSTs(sea surface temperatures) in the South Sea of Korea and intensity of typhoons which passed through the South Sea of Korea was analyzed for 36 years from 1970 to 2005. The SSTs in the South Sea show the rising trends continuously. The mean SST of the last 10 years(1996-2005) is higher $1.03^{\circ}C$ than the mean SST during 10 years(1970-1979). The rising trends are especially strong after 1994. The intensity of typhoon can be shown by the minimum sea level pressure. The minimum sea level pressures of typhoons which passed through the South Sea show the descending trends. The mean minimum sea level pressure of the last 10 years(1996-2005) is lower 10.1hPa than that during 10 years(1970-1979). The correlation analysis shows that the rising of SSTs in the South Sea has relations with the strengthening of intensity of typhoons.

A Study on Water Level Rising Travel Time due to Discharge of Paldang Dam and Tide of Yellow Sea in Downstream Part of Paldang Dam (팔당댐 방류량과 황해(서해) 조석영향에 따른 팔당댐 하류부 수위상승도달시간 예측)

  • Lee, Jong-Kyu;Lee, Jae-Hong
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.2
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    • pp.111-122
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    • 2010
  • As the Jamsu-bridge and the floodplains of the Han River can be flooded during the rainy season, the exact prediction of the peak flood time is very important for mitigation of flood hazard. This study analyzes the effect of outflow of Paldang Dam and tide of Yellow Sea on the Han River. A target area is from the Paldang dam to Jeonryu gauging station. Water level of Jeonryu as a downstream boundary condition was estimated through multi linear regression analysis with outflow of Paldang dam and tide level of Incheon, because it was influenced by both a tide of Yellow Sea and outflow of Paldang dam. In this study, Water Level Rising Travel Time of the Jamsu-bridge and some floodplains in the Han River are estimated. Also, The second order polynomial expressions for relationships of outflow of Paldang Dam and Water Level Rising Travel Time were developed considering the outflow of Paldang dam and tide of Yellow Sea.

SEA LEVEL VARIATIONS IN THE LONG TERM IN THE EAST SEA OF KOREA

  • Cho, Keun-Han;Kim, Hee-Jong;Lee, Dong-In;Yoon, Hong-Joo
    • Proceedings of the KSRS Conference
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    • 2007.10a
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    • pp.37-40
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    • 2007
  • Satellite altimetric data from 1993 to 2006 are used to study sea level variations in the long tenn in the East Sea. The trend of sea level in the East Sea is rising 4.16 mm/yr and indicate that it rose 5.82 cm in 2006 against to 1993. The South Ses is the fastest in the study areas (4.89 mm/yr, 6.84cm) and the Yellow Sea is 4.10 mm/yr and 5.75cm, respectively. The both of Mokho coast and Ulleung island are minimal sea level in March to May and maximal sea level in September to November. For periods above 20.9days, coherences are found to be higher than 95% confidence level, and the phase differences are near zero.

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Long-term Change in Sea Level along the Eastern Coastal Waters of Korea using Tide Gauge, Water Temperature and Salinity (조위 및 수온, 염분 데이터를 이용한 동해 연안의 해수면 변화)

  • Park, Se-Young;Lee, Chung-Il
    • Journal of Environmental Science International
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    • v.23 no.5
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    • pp.801-806
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    • 2014
  • Long-term change in sea level along the eastern coast of Korea was illustrated using four tide-gauge station (Pohang, Mukho, Sokcho, Ulleung) data, water temperature and salinity. Seasonal variation in the sea level change was dominant. The sea level change by steric height derived from water temperature and salinity was relatively lower than that measured from the tide-gauge stations. Sea level rising rate per year by steric height increased with latitude. The effect of salinity(water temperature) on the sea level change is greater in winter(in summer).

Sedimentary Facies and Geomorphological Development of Alluvial Plain at Neungsan-ri, Buyeo, Korea (부여 능산리 충적평야 퇴적상과 지형발달)

  • Yoon, Soon-Ock;Kim, Ae-Sun;Hwang, Sang-Ill
    • The Korean Journal of Quaternary Research
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    • v.24 no.1
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    • pp.35-45
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    • 2010
  • The aims of this study are to clarify the geomorphological development of a alluvial plain and discuss the vegetation environments and agriculture activities in the Wangpo-River alluvial plain at Neungsan-ri, Buyeo by analyzing geomorphological classification, sedimentary facies and age datings. The alluvial plain at Wangpo-River was formed by the influences of Geum-River with the sea-level rising during the Holocene. The basin of Wangpo-River consists of natural levees, back marsh-type alluvial plains, valley plains and hills. The natural levees by Geum-River largely distributes at the area where Wangpo-River flows to Geum-River and the alluvial plains at the middle and lower reach are the back marsh areas of Geum-River. Moreover, the area along Wangpo-River show higher contents of coarse materials and thinner peat sediments than the back marsh. The lower sandy deposits in the alluvium of Wangpo-River was formed with the influences of human in the Bronze Age during the sea level falling and the peaty deposits was formed due to the water level rising of Wangpo-River during the sea level rising in the early Iron Age.

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Time-dependent reliability analysis of coastal defences subjected to changing environments

  • Chen, Hua-Peng
    • Structural Monitoring and Maintenance
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    • v.2 no.1
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    • pp.49-64
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    • 2015
  • This paper presents a method for assessing the risk of wave run-up and overtopping of existing coastal defences and for analysing the probability of failure of the structures under future hydraulic conditions. The recent UK climate projections are employed in the investigations of the influence of changing environments on the long-term performance of sea defences. In order to reduce the risk of wave run-up and overtopping caused by rising sea level and to maintain the present-day allowances for wave run-up height and overtopping discharge, the future necessary increase in crest level of existing structures is investigated. Various critical failure mechanisms are considered for reliability analysis, i.e., erosion of crest by wave overtopping, failure of seaside revetment, and internal erosions within earth sea dykes. The time-dependent reliability of sea dykes is analysed to give probability of failure with time. The results for an example earth dyke section show that the necessary increase in crest level is approximately double of sea level rise to maintain the current allowances. The probability of failure for various failure modes of the earth dyke has a significant increase with time under future hydraulic conditions.

Pacific Sea Level Variability associated with Climate Variability from Altimetry and Sea Level Reconstruction Data (위성 고도계와 해수면 재구성 자료를 이용한 기후변동성에 따른 태평양 해수면 변화)

  • Cha, Sang-Chul;Moon, Jae-Hong
    • Ocean and Polar Research
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    • v.40 no.1
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    • pp.1-13
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    • 2018
  • Previous studies have indicated a great regional difference in Sea Level Rise (SLR) in the Pacific and it has been suggested that this is linked to climate variability over the past two decades. In this study, we seek to identify the possible linkage between regional sea level and Pacific climate variability from altimetry-based sea level data (1993-2012) and further investigate how the Pacific sea level has changed spatially and temporally over the past 60 years from long-term sea level reconstruction data (1953-2008). Based on the same method as Zhang and Church (2012), the Inter-annual Climate Index (ICI) associated with the El $Ni{\tilde{n}}o-Southern$ Oscillation (ENSO) and the Decadal Climate Index (DCI) associated with Pacific Decadal Oscillation (PDO) are defined and then the multiple variable linear regression is used to analyze quantitatively the impact of inter-annual and decadal climate variability on the regional sea levels in the Pacific. During the altimeter period, the ICI that represents ENSO influence on inter-annual time scales strongly impacts in a striking east-west "see-saw mode" on sea levels across the tropical Pacific. On the other hand, the decadal sea level pattern that is linked to the DCI has a broad meridional structure that is roughly symmetric in the equator with its North Pacific expression being similar to the PDO, which largely contributes to a positive SLR trend in the western Pacific and a negative trend in the eastern Pacific over the two most recent decades. Using long-term sea level reconstruction data, we found that the Pacific sea levels have fluctuated in the past over inter-annual and decadal time scales and that strong regional differences are presented. Of particular interest is that the SLR reveals a decadal shift and presents an opposite trend before and after the mid-1980s; i.e., a declining (rising) trend in the western (eastern) Pacific before the mid-1980s, followed by a rising (declining) trend from the mid-1980s onward in the western (eastern) Pacific. This result indicates that the recent SLR patterns revealed from the altimeters have been persistent at least since the mid-1980s.

A Study On the Method for Optimal Selection Tide Observation (조위관측을 위한 최적 기법선정 방법에 관한 연구)

  • Yoon, Dong-Gun;Park, Seon-Dong;Seo, Sang-Il
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2010.04a
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    • pp.333-335
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    • 2010
  • Global warming gas caused an increase in a direct and indirect problems like the rising sea level, seawater overflowing and a coastal flooding. The loss and damage of the republic of korea are increasing because of the rising sea level. As a result, It is necessary to establish the foundation of the monitoring of the sea level changes for the flooding prevention. A new measurement technique is developed using GPS equipped ship to make up for the spatial-temporal and economical problems by this study. We compared the data using GPS with the value for height of the tide. And we corrected the errors using the more accurate data that we studied. In addition to we studied that the corrected value had statistical significance and similarity compared with the observed value using GPS. The following studies also performed : When the observed value of tide by a tide observatory and by using GPS are applied to sounding ; How the values of the water depth are being, and if the values are similar, whether the observed value of tide using GPS is valid or not.

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