• Title/Summary/Keyword: sea level change

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Future Sea Level Projections over the Seas Around Korea from CMIP5 Simulations (CMIP5 자료를 활용한 우리나라 미래 해수면 상승)

  • Heo, Tae-Kyung;Kim, Youngmi;Boo, Kyung-On;Byun, Young-Hwa;Cho, Chunho
    • Atmosphere
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    • v.28 no.1
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    • pp.25-35
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    • 2018
  • This study presents future potential sea level change over the seas surrounding Korea using Climate Model Intercomparison Project Phase 5 9 model ensemble result from Representative Concentration Pathways (RCPs), downloaded from icdc.zmaw.de. At the end of 21st century, regional sea level changes are projected to rise 37.8, 48.1, 47.7, 65.0 cm under RCP2.6, RCP4.5, RCP6.0 and RCP8.5 scenario, respectively with the large uncertainty from about 40 to 60 cm. The results exhibit similar tendency with the global mean sea level rise (SLR) with small differences less than about 3 cm. For the East Sea, the Yellow Sea, and the southern sea of Korea, projected SLR in the Yellow Sea is smaller and SLR in the southern sea is larger than the other coastal seas. Differences among the seas are small within the range of 4 cm. Meanwhile, Commonwealth Scientific and Industrial Research Organization (CSIRO) data in 23 years shows that the mean rate of sea level changes around the Yellow Sea is high relative to the other coastal seas. For sea level change, contribution of ice and ocean related components are important, at local scale, Glacial Isostatic Adujstment also needs to be considered.

Change of Mean Sea Level due to Coastal Development and Climate Change in the Western Coast of Korean Peninsula (해안개발과 기후변화로 인한 서해 연안해역의 평균해수면 변화)

  • Jung, Tae Sung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.26 no.3
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    • pp.120-130
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    • 2014
  • Change of mean sea level in the western coast of Korean peninsula was estimated with the observed tide data of the KHOA. The cause of the change was investigated. Mean sea levels in the western coast have been changed due to coastal development projects in the coastal zone. The estimated variations, which are significantly different regionally, vary from -6.8 cm in Incheon to 38 cm in Gunsan. The changing rate of mean sea level occurred by natural factors such as global warming varies from 1.1 mm/year in the north to 4.4 mm/year in the south of western coast of Korean peninsula. In Jeju, sea level rise and rise of sea temperature showed a close relationship. Water temperature rise of one degree increases mean sea level to 0.6 mm in Jeju. Rising rate of mean sea level has increased rapidly after the mid-1980s.

Modeling the long-term vegetation dynamics of a backbarrier salt marsh in the Danish Wadden Sea

  • Daehyun Kim
    • Journal of Ecology and Environment
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    • v.47 no.2
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    • pp.49-62
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    • 2023
  • Background: Over the past three decades, gradual eustatic sea-level rise has been considered a primary exogenous factor in the increased frequency of flooding and biological changes in several salt marshes. Under this paradigm, the potential importance of short-term events, such as ocean storminess, in coastal hydrology and ecology is underrepresented in the literature. In this study, a simulation was developed to evaluate the influence of wind waves driven by atmospheric oscillations on sedimentary and vegetation dynamics at the Skallingen salt marsh in southwestern Denmark. The model was built based on long-term data of mean sea level, sediment accretion, and plant species composition collected at the Skallingen salt marsh from 1933-2006. In the model, the submergence frequency (number yr-1) was estimated as a combined function of wind-driven high water level (HWL) events (> 80 cm Danish Ordnance Datum) affected by the North Atlantic Oscillation (NAO) and changes in surface elevation (cm yr-1). Vegetation dynamics were represented as transitions between successional stages controlled by flooding effects. Two types of simulations were performed: (1) baseline modeling, which assumed no effect of wind-driven sea-level change, and (2) experimental modeling, which considered both normal tidal activity and wind-driven sea-level change. Results: Experimental modeling successfully represented the patterns of vegetation change observed in the field. It realistically simulated a retarded or retrogressive successional state dominated by early- to mid-successional species, despite a continuous increase in surface elevation at Skallingen. This situation is believed to be caused by an increase in extreme HWL events that cannot occur without meteorological ocean storms. In contrast, baseline modeling showed progressive succession towards the predominance of late-successional species, which was not the then-current state in the marsh. Conclusions: These findings support the hypothesis that variations in the NAO index toward its positive phase have increased storminess and wind tides on the North Sea surface (especially since the 1980s). This led to an increased frequency and duration of submergence and delayed ecological succession. Researchers should therefore employ a multitemporal perspective, recognizing the importance of short-term sea-level changes nested within long-term gradual trends.

Development and Application of a Methodologyfor Climate Change Vulnerability Assessment-Sea Level Rise Impact ona Coastal City (기후변화 취약성 평가 방법론의 개발 및 적용 해수면 상승을 중심으로)

  • Yoo, Ga-Young;Park, Sung-Woo;Chung, Dong-Ki;Kang, Ho-Jeong;Hwang, Jin-Hwan
    • Journal of Environmental Policy
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    • v.9 no.2
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    • pp.185-205
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    • 2010
  • Climate change vulnerability assessment based on local conditions is a prerequisite for establishment of climate change adaptation policies. While some studies have developed a methodology for vulnerability assessment at the national level using statistical data, few attempts, whether domestic or overseas, have been made to develop methods for local vulnerability assessments that are easily applicable to a single city. Accordingly, the objective of this study was to develop a conceptual framework for climate change vulnerability, and then develop a general methodology for assessment at the regional level applied to a single coastal city, Mokpo, in Jeolla province, Korea. We followed the conceptual framework of climate change vulnerability proposed by the IPCC (1996) which consists of "climate exposure," "systemic sensitivity," and "systemic adaptive capacity." "Climate exposure" was designated as sea level rises of 1, 2, 3, 4, and 5 meter(s), allowing for a simple scenario for sea level rises. Should more complex forecasts of sea level rises be required later, the methodology developed herein can be easily scaled and transferred to other projects. Mokpo was chosen as a seaside city on the southwest coast of Korea, where all cities have experienced rising sea levels. Mokpo has experienced the largest sea level increases of all, and is a region where abnormal high tide events have become a significant threat; especially subsequent to the construction of an estuary dam and breakwaters. Sensitivity to sea level rises was measured by the percentage of flooded area for each administrative region within Mokpo evaluated via simulations using GIS techniques. Population density, particularly that of senior citizens, was also factored in. Adaptive capacity was considered from both the "hardware" and "software" aspects. "Hardware" adaptive capacity was incorporated by considering the presence (or lack thereof) of breakwaters and seawalls, as well as their height. "Software" adaptive capacity was measured using a survey method. The survey questionnaire included economic status, awareness of climate change impact and adaptation, governance, and policy, and was distributed to 75 governmental officials working for Mokpo. Vulnerability to sea level rises was assessed by subtracting adaptive capacity from the sensitivity index. Application of the methodology to Mokpo indicated vulnerability was high for seven out of 20 administrative districts. The results of our methodology provides significant policy implications for the development of climate change adaptation policy as follows: 1) regions with high priority for climate change adaptation measures can be selected through a correlation diagram between vulnerabilities and records of previous flood damage, and 2) after review of existing short, mid, and long-term plans or projects in high priority areas, appropriate adaptation measures can be taken as per this study. Future studies should focus on expanding analysis of climate change exposure from sea level rises to other adverse climate related events, including heat waves, torrential rain, and drought etc.

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Relative Sea-level Change Around the Korean Peninsula

  • Jeon, Dong-Chull
    • Ocean and Polar Research
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    • v.30 no.4
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    • pp.373-378
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    • 2008
  • Long-term tide-gauge data from around the Korean Peninsula were reanalyzed. Both the coastal water and the open sea surrounding the Korean Peninsula appeared to have been influenced by global warming. The long-term change in relative sea levels obtained from tidal stations showed a general rising trend, especially near Jeju Island. It is proposed that global warming may have caused shifting of the path of the Kuroshio branch (Tsushima Warm Current) toward Jeju Island, causing a persistent increase in the water levels along the coast of the island over the last few decades.

Space-time-dissociated differential sedimentation and its relationship with the rate of relative sea-level change: the Lower Ordovician Mungok Formation, Korea

  • Choi Yong Seok;Lee Yong Il
    • 한국석유지질학회:학술대회논문집
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    • autumn
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    • pp.14-30
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    • 2000
  • Hierarchically controlled sequence stratigraphic analysis shows that the Lower Ordovician mixed carbonate-siliciclastic Mungok Formation, Korea consists of three depositional sequences: T1, T2, and T3. Sequence boundaries are generally marked by abrupt transition from coarse-grained shallow-water carbonates to fine-grained deeper-water carbonates mixed with fine-grained siliciclastics, and show indication of subaerial exposure such as karstification. Within this sequence stratigraphic framework, facies characteristics indicate that the Mungok sequences were mostly deposited in subtidal ramp environments. High-frequency cycles consist of upward-shallowing facies successions. Cycles of shallow-water and basinal deposits are not represented well, probably due to cycle amalgamation. Cycle stacking patterns do not show a consistent thickness change that reflects a large-scale sea-level change due to unfilled accommodation space. The Mungok sequences show that many factors including relative sea-level change and topography are involved in controlling sequence development on carbonate ramps. The depositional setting evolved from the high-energy ramps in the sequences T1 and T2 into the low-energy ramp in the sequence T3. Topography is interpreted to have been responsible for the different energy regimes of the carbonate ramps in the Mungok sequences. The high ramp gradient in the sequences T1 and T2 seems to be caused by space-time-dissociated differential sedimentation resulting in spatially narrow distribution of sediment filling, which in turn may be related to high rate of relative sea-level change. In contrast, low ramp gradient was maintained in the sequence T3 during slow changes of relative sea level resulting in broad distribution of sediment filling.

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VULNERABILITY OF KOREAN COAST TO THE SEA-LEVEL RISE DUE TO $21^{ST}$ GLOBAL WARMING

  • Cho Kwangwoo;Maeng Jun Ho;Yun Jong-Hwui
    • Proceedings of KOSOMES biannual meeting
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    • 2003.11a
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    • pp.219-225
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    • 2003
  • The present study intends to assess the long-term steric sea-level change and its prediction, and potential impacts to the sea-level rise due to the 21st global warming in the coastal zone of the Korea in which much socioeconomic activities have been occurred. The analysis of the 23 tide-gauge data near Korea reveals the overall mean sea-level trend of 2.31 mm/yr.In the satellite altimeter data (Topex/Poseidon and ERS), the sea-level trend in the East Sea is 4.6mm/yr. Both are larger than those of the global average value. However, it is quite questionable that the sea-level trends with the tide-gauge data on the neighboring seas of Korea relate to global warming because of the relatively short observation period and large spatial variability. It is also not clear whether the high trend of altimeter data in the East Sea is related to the acceleration of sea level rise in the Sea, short response time of the Sea, natural variability such as decadal variability, short duration of the altimeter. The coastal zone of Korea appears to be quite vulnerable to the 21st sea level rise such that for the I-m sea level rise with high tide and storm surge, the inundation area is 2,643 km2, which is about $1.2\%$ of total area and the population in the risk areas of inundation is 1.255 million, about $2.6\%$ of total population. The coastal zone west of Korea is appeared to be the most vulnerable area compared to the east and south. In the west of the Korea, the North Korea appears to be more vulnerable than South Korea. In order to cope with the future possible impact of sea-level rise to the coastal zone of Korea effectively, it is essential to improve scientific information in the sea-level rise trend, regional prediction, and vulnerability assessment near Korean coast.

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The Change of the Depositional Environment on Dodaecheon River Basin during the Middle Holocene (Holocene 中期에 있어서 道垈川流域의 堆積 環境 變化)

  • Hwang, Sang-Ill;Yoon, Soon-Ock;Jo, Wha-Ryong
    • Journal of the Korean Geographical Society
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    • v.32 no.4
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    • pp.403-420
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    • 1997
  • Dodaecheon is a small river flowing into Asan Bay which is located in the middle part of the West Coast of the Korean Penninsula. We have investigated the change of depositional environment in Dodaecheon river basin during the middle Holocene. In the course of the research, the methods such as boring, radiocarbon dating, diatom and pollen analysis were employed. The Holocene deposits of the studied area are consisted of peat and gray silt layers, and contain many plooen and diatom fossils. Based on the results of diatom and pollen analysis, we conclude that the gray silt layers were sedimented owing to the transgression in the middle Holocene, and the peat layers by the regression or stabilzation of the sea level. The shoreline in the Post Glacial Age reached to the rivemouth of Dodaecheon at ca. 7,000 years before present(y. BP) and at that time the high tide sea-level(mean high water level of spring tide) rose to ca. 3m above present mean sea-level(m.a.s.l.). Since then to ca. 6,000y. BP, the high tide sea-level arrived to ca. 5m above present mean sea level further repeating minor transgressions and regressions. The peat layers of the coastal lowland of the West Coast were formed by the sea level fluctuations from 7,000 y. BP to 3,000 y. BP, and they were distributed 2 to 6 meters higher than the mean sea level of the present day. Most of them sedimented due to the high tide level are older and higher than those of the East Coast which were formed at the swale in the low tidal range environment.

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Sea Level Rise at the Southwestern Coast of Korean Peninsula

  • Oh Nam-Sun;Kang Ju-Whan;Moon Seung-Rok
    • Journal of Navigation and Port Research
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    • v.29 no.4
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    • pp.327-333
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    • 2005
  • Sea level (MSL, MHWL, or MLWL) change has been main concern to scientists and engineers and it can be primarily due to both change of climate and vertical movement of land. This paper reports the intensive analysis of the sea level changes and broad discussion of the future at the southwestern coast of Korean peninsula. Regression analysis was conducted to investigate general tendency and periodicity of the sea levels at the six different study sites such as Gunsan-I(inner port), Gunsan-O(outer port), Mokpo, Yeosu, Heuksan and Jeju and the results were compared with global values. Besides the changes of sea levels due to global warming, the influence of the man-made structure such as seadike and seawall was attempted to quantify using the minimization of the Root Mean Square(RMS) error. The results show that it is a general tendency that the values of mean sea level rise at the southwestern coast of Korean Peninsula, especially at Gunsan-I and Jeju, are somewhat larger compared to global average values. There is also some evidence that tidal amplifications are found just after construction of man-made structure at Gunsan-I and Mokpo. However, both sites show different mechanism in relation to tidal choking, tidal flat and river discharge. The impact due to construction of man-made structure is considerably larger at Mokpo site, while the impacts due to man-made structure and the effect of sea level rise are relatively identical at Gunsan-I site. This study is expected to provide some intuition to future design.

A Study on Trend Analysis in Sea Level Data Through MK Test and Quantile Regression Analysis (MK 검정 및 분위회귀분석을 통한 해수면 자료의 경향성 평가에 관한 연구)

  • Uranchimeg, Sumiya;Kim, Yong-Tak;Kwon, Hyun-Han;Hwang, Kyu-Nam
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.27 no.2
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    • pp.94-104
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    • 2015
  • Population and urban development along the coast is growing in South Korea, and particularly sea level rise is likely to increase the vulnerability of coastal areas. This study aims to investigate the sea level rise through Mann-Kendall(MK) test, ordinary linear regression(OR) and quantile regression analysis(QRA) with sea level data at the 20 tide stations along the coast of Korean Peninsula. First, statistically significant long-term trends were analysed using a non-parametric MK test and the test indicated statistically significant trends for 18 and 10 stations at the 5% significance level in the annual mean value of sea level and the annual maximum value of sea level, respectively. The QRA method showed better performance in terms of characterizing the degree of trend. QRA showed that an average annual rise in mean sea level is about 1-6 mm/year, and an average rise in maximum sea level is about 1-20 mm. It was found that upward convergent and upward divergent were a representative change given the nine-category distributional changes. We expect that in future work we will address nonstationarities with respect to sea level that were identified above, and develop a nonstationary frequency analysis with climate change scenarios.