• Title/Summary/Keyword: Coastal regions

Search Result 672, Processing Time 0.028 seconds

Numerical Analysis of Wind Driven Current and Mesoscale Air Flow in Coastal Region with Land Topography (육상지형을 고려한 연안해역에서의 취송류에 관한 수치해석)

  • Lee, Seong-Dae;Kim, In-Ho;Hong, Chang-Bae
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2006.05a
    • /
    • pp.1925-1930
    • /
    • 2006
  • A quasi depth-varying mathematical model for wind-generated circulation in coastal areas, expressed in terms of the depth-averaged horizontal velocity components and free surface elevation was validated and used to understand the diurnal circulation process. The wind velocity is considered as a dominant factor for driving the wind generated current. In this paper, three dimensional numerical experiments that included the land topography were used to investigate the mesoscale air flow over the coastal regions. The surface temperature of the inland was determined through the surface heat budget consideration with inclusion of a layer of vegetation. A series of numerical experiments were then carried out to investigate the diurnal response of the air flow and wind-generated circulation to various types of surface inhomogeneities.

  • PDF

Interannual Variability and Long-term Trend of Coastal Sea Surface Temperature in Korea (한국 연안 표층수온의 경년변동과 장기변화)

  • Min, Hong-Sik;Kim, Cheol-Ho
    • Ocean and Polar Research
    • /
    • v.28 no.4
    • /
    • pp.415-423
    • /
    • 2006
  • Interannual variation and long-term trends of coastal sea surface temperature (SST) in Korea were investigated by analyzing 27 coastal SST time series from 1969 to 2004. Long-term linear increasing trend was remarkable with the rate over $0.02^{\circ}C/year$ at almost all the stations. The slope of long-term linear trend was larger at the stations along the eastern coast than in the western and southern regions. It was also noticeable that there was a common tendency of interannual variability with the period of 3-5 years at most of the stations. SST was lower in the 1970's and early 1980's while it was higher in the 1990's and early 2000's after the increase in the late 1980's. The pattern of the interannual variability of SST was similar to that of air temperature. Increasing trend of minimum SST in winter was obvious at most stations na it was larger along the eastern coast, while the linear trend of maximum SST in summer was less definite. Therefore, the decreasing tendency of annual amplitude was mainly due to the increasing tendency of SST in winter.

Sediment Fluxes in Shelf Seas Modelling and Monitoring

  • Prandel, David
    • Journal of the korean society of oceanography
    • /
    • v.37 no.3
    • /
    • pp.144-153
    • /
    • 2002
  • This is a review paper, assessing progress reported in a Special Issue (Prandle and Lane, 2000) of Coastal Engineering focusing on simulation of SPM in the North Sea, against issues over a diverse range of shelf seas and their coastal margins. The broad objectives of reproducing the characteristics of sediment fluxes off an open coast and relating these to tidal and wave forcing were achieved. However, accurate computation of these fluxes remains sensitive to largely empirical coefficients used in determining erosion and deposition rates. Bed roughness strongly influences both these coefficients and the associated near-bed current magnitudes (including wave impact thereon). Bed roughness can change significantly over a tidal cycle and dramatically over seasons or in the course of a major event. Accurate simulation of sediment fluxes on a day-to-day basis is constrained by dependency on the initial distribution of mobile sediments. The latter depends on rates and locations of original sources and the time history of preceding events. Remote sensing via aircraft could provide data for assimilation into such models to circumvent these constraints. The approaches described here can be readily applied to other coastal regions to indicate the likely distributions and pathways of known sediment sources. However quantitative simulations will require an associated observational programme. A subsequent stage is to understand the evolving balance between the forecasted sediment movement - the resulting morphological adjustments and thence modifications to the prevailing tidal current and wave regimes.

Distribution, Characterization, and Diversity of the Endophytic Fungal Communities on Korean Seacoasts Showing Contrasting Geographic Conditions

  • You, Young-Hyun;Park, Jong Myong;Seo, Yeong Gyo;Lee, Woong;Kang, Myung-Suk;Kim, Jong-Guk
    • Mycobiology
    • /
    • v.45 no.3
    • /
    • pp.150-159
    • /
    • 2017
  • This study analyzed the distribution of endophytic fungi in 3 coastal environments with different climatic, geographical, and geological characteristics: the volcanic islands of Dokdo, the East Sea, and the West Sea of Korea. The isolated fungal endophytes were characterized and analyzed with respect to the characteristics of their host environments. For this purpose, we selected common native coastal halophyte communities from three regions. Molecular identification of the fungal endophytes showed clear differences among the sampling sites and halophyte host species. Isolates were also characterized by growth at specific salinities or pH gradients, with reference to previous geographical, geological, and climate studies. Unlike the East Sea or West Sea isolates, some Dokdo Islands isolates showed endurable traits with growth in high salinity, and many showed growth under extremely alkaline conditions. A smaller proportion of West Sea coast isolates tolerate compared to the East Sea or Dokdo Islands isolates. These results suggest that these unique fungal biota developed through a close interaction between the host halophyte and their environment, even within the same halophyte species. Therefore, this study proposes the application of specific fungal resources for restoring sand dunes and salt-damaged agricultural lands and industrialization of halophytic plants.

Diversity and Saline Resistance of Endophytic Fungi Associated with Pinus thunbergii in Coastal Shelterbelts of Korea

  • Min, Young Ju;Park, Myung Soo;Fong, Jonathan J.;Quan, Ying;Jung, Sungcheol;Lim, Young Woon
    • Journal of Microbiology and Biotechnology
    • /
    • v.24 no.3
    • /
    • pp.324-333
    • /
    • 2014
  • The Black Pine, Pinus thunbergii, is widely distributed along the eastern coast of Korea and its importance as a shelterbelt was highlighted after tsunamis in Indonesia and Japan. The root endophytic diversity of P. thunbergii was investigated in three coastal regions; Goseong, Uljin, and Busan. Fungi were isolated from the root tips, and growth rates of pure cultures were measured and compared between PDA with and without 3% NaCl to determine their saline resistance. A total of 259 isolates were divided into 136 morphotypes, of which internal transcribed spacer region sequences identified 58 species. Representatives of each major fungi phylum were present: 44 Ascomycota, 8 Zygomycota, and 6 Basidiomycota. Eighteen species exhibited saline resistance, many of which were Penicillium and Trichoderma species. Shoreline habitats harbored higher saline-tolerant endophytic diversity compared with inland sites. This investigation indicates that endophytes of P. thunbergii living closer to the coast may have higher resistance to salinity and potentially have specific relationships with P. thunbergii.

Influence of Water Temperature on Air Temperature around Eastern and Western Coastal Areas of the Korean Peninsula during Winter (동계 한반도 동·서 연안역 기온에 미치는 수온의 영향)

  • Hong, Chul-Hoon
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.52 no.1
    • /
    • pp.92-96
    • /
    • 2019
  • The influence of water temperature (WT) on air temperature (AT) in the eastern and western coastal regions of the Korean peninsula in the winter was investigated using historical data from the Korean Meteorological Agency (KMA) and the National Institute of Fisheries Science (NIFS), focusing on the relationship between AT and WT. The data analysis shows that, during winter, the AT is generally higher by +1.9 to $+2.7^{\circ}C$ at Kangreung ($37.2^{\circ}N$) in the eastern region than at Inchon ($37.4^{\circ}N$) in the western region, i.e., the AT in the eastern region of the Korean Peninsula tends to be higher overall than that in the western region when similar latitudes are compared. On the other hand, in the winters of 1977-2006, the WT at Sokcho was higher by $+0.8^{\circ}C$ (January) to $+2.3^{\circ}C$ (March) than that at Sochungdo, directly resulting in increased AT ($+1.22^{\circ}C$) at Sokcho. This study suggests that higher AT in the eastern region during winter is caused by the influence of water flow, such as the East Korean Warm Current in the East/Japan Sea.

Anthropogenic Fingerprint on Recent Changes in Typhoon Heavy Rainfall beyond Tipping-Point (최근 태풍 호우에서 보이는 인류세 지문의 변화: 임계점을 넘어서)

  • Hyungjun Kim;Nobuyuki Utsumi
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2023.05a
    • /
    • pp.87-87
    • /
    • 2023
  • The impact of climate change on typhoons is a major concern in East Asia, especially due to the destructive effects of heavy rainfall on society and the economy, as many megacities are located along coastal regions. Although observations suggest significant changes in typhoon heavy rainfall, the extent to which anthropogenic forcing contributes to these changes has yet to be determined. In this study, we demonstrate that anthropogenic global warming has a substantial impact on the observed changes in typhoon heavy rainfall in the western North Pacific region. Observation data indicates that, in general, typhoon heavy rainfall has increased (decreased) in coastal East Asia (tropical western North Pacific) during the latter half of the 20th century and beyond. This spatial distribution is similar to the "anthropogenic fingerprint" observed from a set of large ensemble climate simulations, which represents the difference between Earth systems with and without human-induced greenhouse gas emissions. This provides evidence to support the claim that the significant increase in the frequency of typhoon heavy rainfall along coastal East Asia cannot be solely explained by natural variability. In addition, our results indicate that the signal of the "anthropogenic fingerprint" has been increasing rapidly since the mid-1970s and departed from natural variability in the early 2000s, indicating that the regional summer climate has already crossed the tipping point.

  • PDF

Sequence Analysis of Cochlodinium polykrikoides Isolated from Korean Coastal Waters Using Sequences of Internal Transcribed Spacers and 5.8S rDNA

  • Kim, Hak-Gyoon;Cho, Yong-Chul;Cho, Eun-Seob
    • Journal of the korean society of oceanography
    • /
    • v.35 no.3
    • /
    • pp.158-160
    • /
    • 2000
  • The relativity of four isolates of C. polykrikoides was determined by comparative sequence analysis based on direct sequencing of PCR amplified ribosomal DNA (the internal transcribed spacer region and the 5.8S rDNA). Sequence comparisons indicated that four isolates had the same nucleotide sites in the ITS regions, as well as a total of 585 nucleotide length and 100% homology. The molecular data revealed that C. polykrikoides in Korean coastal waters show no genetical difference.

  • PDF

Development of a Low-cost Solar Fish Dryer in Context to Fish Drying in Bangladesh

  • Alam, A.K.M. Nowsad;Khan, M.N. Absar
    • Journal of Marine Bioscience and Biotechnology
    • /
    • v.2 no.1
    • /
    • pp.23-33
    • /
    • 2007
  • The constraints of traditional fish drying in Bangladesh have been reviewed and an effective solar fish dryer was developed with the small-scale processors and fishermen using locally available cheaper materials in order to dry fish in coastal region. After successful field testing, new solar dryer was demonstrated within the community in 3 different locations of Cox's Bazar for several batches of operations in each location from late September to March and found very effective in terms of architectural suitability, operational feasibility, technical efficiency, out-put quality (good texture, colour, flavour and long storage time), user's acceptability, commercial viability and environmental adequacy. A simple cost-profit analysis was done with the community operated products, which indicates that the new solar fish dryers could be operated profitably in coastal regions where sun-light and air flows are abundant.

  • PDF

A Fundamental Study on the Application of the Period in Cold Weather Concrete (한중 콘크리트의 적용기간 설정에 관한 기초적 연구)

  • 한민철;백승대;윤기원;한천구;김무한
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 1996.04a
    • /
    • pp.408-413
    • /
    • 1996
  • The purpose of this study is to present the reference data about the period in cold weather concrete practice based on meteorological data of Korea meteorological administration in our country in comparison with previous study and specifications of foreign country as to cold weather concrete such as ACI, JASS-5 and JSCE. The results of this study indicate that the period of cold weather concrete by each specifications in most of the region except Cheju island and coastal region in Korea is lasted over 100 days and the period of cold weather concrete in hillsides and inland areas is longer than that of coastal regions in the same latitude.

  • PDF