• Title/Summary/Keyword: deep earth science

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Fifty Years of Scientific Ocean Drilling (1968-2018): Achievements and Future Direction of K-IODP (해양 과학시추 50년 (1968-2018): 한국의 성과 및 미래 방향)

  • KIM, GIL YOUNG
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.24 no.1
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    • pp.30-48
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    • 2019
  • The year 2018 is the $50^{th}$ anniversary of scientific ocean drilling. Nevertheless, we know more about the surface of the moon than the Earth's ocean floor. In other words, there are still no much informations about the Earth interior. Much of what we do know has come from the scientific ocean drilling, providing the systematic collection of core samples from the deep seabed. This revolutionary process began 50 years ago, when the drilling vessel Glomar Challenger sailed into the Gulf of Mexico on August 11, 1968 on the first expedition of the federally funded Deep Sea Drilling Project (DSDP). DSDP followed successively by Ocean Drilling Program (ODP), Integrated Ocean Drilling Program (old IODP), and International Ocean Discovery Program (new IODP). Concerning on the results of scientific ocean drilling, there are two technological innovations and various scientific research results. The one is a dynamic positioning system, enables the drilling vessel to stay fixed in place while drilling and recovering cores in the deep water. Another is the finding of re-entry cone to replace drill bit during the drilling. In addition to technological innovation, there are important scientific results such as confirmation of plate tectonics, reconstruction of earth's history, and finding of life within sediments. New IODP has begun in October, 2013 and will continue till 2023. IODP member countries are preparing for the IODP science plan beyond 2023 and future 50 years of scientific ocean drilling. We as IODP member also need to participate in keeping with the international trend.

Rest-frame optical spectroscopic properties of submillimeter galaxies

  • Shim, Hyunjin
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.74.3-74.3
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    • 2017
  • Considering the statistical redshift distribution of the known submillimeter galaxy (SMG) population, most of the significant optical emission lines such as [OII]${\lambda}3727$, $H{\beta}$, [OIII]${\lambda}5007$, and $H{\alpha}$ are redshifted into near-infrared. Using the 3D-HST grism data that provides low resolution NIR spectroscopy over the several deep fields covered by the JCMT large program S2CLS, I investigated the properties of the optical emission lines for submm galaxies which could be used as a proxy for future optical/NIR identification and follow up of the SMGs.

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Spatio-temporal Distributions of the Wind Stress and the Thermocline in the East Sea of Korea

  • NA Jung-Yul;HAN Sang-Kyu
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.21 no.6
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    • pp.341-350
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    • 1988
  • The wind stress distribution over the East Sea of Korea was obtained from the shipboard observations of the Fisheries Research and Development Agency along the serial observation lines. These monthly and annual mean wind stress distributions were put into the simplified interface model which describes the latitudinal variations of the upper-layer thickness as function of the curl of the wind stress. The observed variations of the surface, zonally averaged winds indeed caused the upper-layer flow convergent and divergent at the latitudes that produced a tone of thick upper-layer or a deep permanent thermocline and the shallower depth with divergence. Thus, the wind field contributes positively to maintain the almost time-independent distribution of the interface of 'saddle like' feature in north-south direction over the study area.

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DEEP-South : Moving Object Detection Experiments

  • Oh, Young-Seok;Bae, Yeong-Ho;Kim, Myung-Jin;Roh, Dong-Goo;Jin, Ho;Moon, Hong-Kyu;Park, Jintae;Lee, Hee-Jae;Yim, Hong-Suh;Choi, Young-Jun
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.1
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    • pp.75.4-76
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    • 2016
  • DEEP-South (Deep Ecliptic patrol of the Southern sky) is one of the secondary science projects of KMTNet (Korea Microlensing Telescope Network). The objective of this project is twofold, the physical characterization and the discovery of small Solar System bodies, focused on NEOs (Near Earth objects). In order to achieve the goals, we are implementing a software package to detect and report moving objects in the $18k{\times}18k$ mosaic CCD images of KMTNet. In this paper, we present preliminary results of the moving object detection experiments using the prototype MODP (Moving Object Detection Program). We utilize multiple images that are being taken at three KMTNet sites, towards the same target fields (TFs) obtained at different epochs. This prototype package employs existing softwares such as SExtractor (Source-Extracto) and SCAMP (Software for Calibrating Astrometry and Photometry); SExtractor generates catalogs, while SCAMP conducts precision astrometric calibration, then MODP determines if a point source is moving. We evaluated the astrometric accuracy and efficiency of the current version of MODP. The plan for upgrading MODP will also be mentioned.

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Occurrence of Pyrobitumen in the Lower Cretaceous Jinju Formation, Korea (하부 백악기 진주층에서 산출되는 고열역청(pyrobitumen)의 산상)

  • Choi, Taejin;Lim, Hyoun Soo;Lee, Jae Il;Lee, Yong Il
    • Journal of the Korean earth science society
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    • v.43 no.5
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    • pp.639-646
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    • 2022
  • Occurrence of black opaque hydrocarbon (pyrobitumen) in some Cretaceous Jinju sandstones of the Sindong Group, Gyeongsang Basin in Korea is first reported in this study. The pyrobitumen is developed on chlorite pore-lining cement, or impregnated into the outer zone of chlorite cement. Therefore, it seems to have been formed after the precipitation of chlorite cement, indicating the former presence of crude oil. The liquid hydrocarbons migrated into sandstones during moderate burial and these sandstones seem to have acted as a liquid hydrocarbon reservoir. The presence of pyrobitumen in the Jinju Formation indicates that this formation underwent deep burial after liquid hydrocarbon migration. As reservoir temperatures increased further, hydrocarbons were cracked and a solid pyrobitumen residue remained in the reservoir.

Environmental Monitoring and Forecasting Using Advanced Remote Sensing Approaches (최신 원격탐사 기법을 이용한 지구환경 모니터링 및 예측)

  • Seonyoung Park;Ahram Song;Yangwon Lee;Jungho Im
    • Korean Journal of Remote Sensing
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    • v.39 no.5_3
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    • pp.885-890
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    • 2023
  • As satellite technology progresses, a growing number of satellites-like CubeSat and radar satellites-are available with a higher spectral and spatial resolutions than previous. National initiatives used to be the main force behind satellite development, but current trendsindicate that private enterprises are also actively exploring and developing new satellite technologies. This special issue examines the recent research results and advanced technology in remote sensing approaches for Earth environment analysis. These results provide important information for the development of satellite sensors in the future and are of great interest to researchers working with artificial intelligence in thisfield. The special issue introduces the latest advances in remote sensing technology and highlights studies that make use of data to monitor and forecast Earth's environment. The objective is to provide direction for the future of remote sensing research.

Long-term and Real-time Monitoring System of the East/Japan Sea

  • Kim, Kuh;Kim, Yun-Bae;Park, Jong-Jin;Nam, Sung-Hyun;Park, Kyung-Ae;Chang, Kyung-Il
    • Ocean Science Journal
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    • v.40 no.1
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    • pp.25-44
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    • 2005
  • Long-term, continuous, and real-time ocean monitoring has been undertaken in order to evaluate various oceanographic phenomena and processes in the East/Japan Sea. Recent technical advances combined with our concerted efforts have allowed us to establish a real-time monitoring system and to accumulate considerable knowledge on what has been taking place in water properties, current systems, and circulation in the East Sea. We have obtained information on volume transport across the Korea Strait through cable voltage measurements and continuous temperature and salinity profile data from ARGO floats placed throughout entire East Sea since 1997. These ARGO float data have been utilized to estimate deep current, inertial kinetic energy, and changes in water mass, especially in the northern East Sea. We have also developed the East Sea Real-time Ocean Buoy (ESROB) in coastal regions and made continual improvements till it has evolved into the most up-to-date and effective monitoring system as a result of remarkable technical progress in data communication systems. Atmospheric and oceanic measurements by ESROB have contributed to the recognition of coastal wind variability, current fluctuations, and internal waves near and off the eastern coast of Korea. Long-tenn current meter moorings have been in operation since 1996 between Ulleungdo and Dokdo to monitor the interbasin deep water exchanges between the Japanese and Ulleung Basins. In addition, remotely sensed satellite data could facilitate the investigation of atmospheric and oceanic surface conditions such as sea surface temperature (SST), sea surface height, near-surface winds, oceanic color, surface roughness, and so on. These satellite data revealed surface frontal structures with a fairly good spatial resolution, seasonal cycle of SST, atmospheric wind forcing, geostrophic current anomalies, and biogeochemical processes associated with physical forcing and processes. Since the East Sea has been recognized as a natural laboratory for global oceanic changes and a clue to abrupt climate change, we aim at constructing a 4-D continuous real-time monitoring system, over a decade at least, using the most advanced techniques to understand a variety of oceanic processes in the East Sea.

Identification of MgII Absorbers in the Quasar Lines of Sight

  • Shim, Hyunjin
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.75.3-75.3
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    • 2015
  • Large area infrared surveys are often accompanied with follow-up optical spectroscopic surveys that has a significant legacy value even for other areas of research. Using these spectral database, we have performed a search for MgII absorption lines in the optical spectrum of background quasar. Over the ~4deg2 of AKARI North Ecliptic Pole survey field and Spitzer First Look Survey field, 18 and 16 MgII absorber systems are identified respectively. The redshift range for the background quasars was 1.0<$z_{qso}$<3.4, while the redshift range for the absorber was 0.6<$z_{abs}$<1.6. Galaxies responsible for MgII absorptions are identified in the deep optical images (CFHT r-band), yet the identification still remains ambiguous for 60% of the systems due to the limited image depth and the source crowdedness. The impact parameter ranges 20-60kpc, and the rest-frame equivalent width of MgII absorption ranges $0.7-4{\AA}$. The most critical part in the identification of MgII absorber galaxies is the existence of deep optical images in addition to the high S/N quasar spectrum with R>3000.

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Geoacoustic Model of Erosional Shelf Ridges in the Mid-eastern Yellow Sea

  • Woo Hun Ryang;Seong-Pil Kim
    • Journal of the Korean earth science society
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    • v.45 no.4
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    • pp.338-348
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    • 2024
  • In the mid-eastern part of the Yellow Sea, large-scale shelf ridges originated from erosion on sand-mud successions that have been presently eroded by strong tidal currents. A three-layered in situ geoacoustic model is provided down to 50 m for the subbottom sedimentary succession of a 45 m water depth using the Hamilton method. The succession is divisible into two-type units of Type-A and Type-B using high-resolution seismic profiles with a deep-drilled YSDP-104 core of 44.0 m in depth below the seafloor. Type-A unit mainly comprises sandy or gravelly sediments, whereas Type-B unit mostly consists of tidal muddy sediments with some thinner sand beds. P-wave speed values are positively compatible with the mean grain size and sediment type of the core sediments. For actual modeling, the geoacoustic property values of the models were compensated to in situ depth values below the seafloor. The detailed geoacoustic model contributes to simulating sound transmission through the sedimentary successions in erosional shelf ridges of variable geoacoustic properties distributed in shallow-water environments of the mid-eastern Yellow Sea.

Application of Stable Isotopes to Tracing Geographical Origin of Food and to Determining Its Authenticity (안정동위원소를 이용한 식품의 원산지 추적과 진위 감별)

  • Bong, Yeon-Sik;Ryu, Jong-Sik;Lee, Kwang-Sik
    • Economic and Environmental Geology
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    • v.42 no.6
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    • pp.645-654
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    • 2009
  • Recently there have been increasing consumers' interests in the geographical origin of foods, due to the FTA (Free Trade Agreement) in the global market. Especially, in Korea, in relation to BSE (bovine spongiform encephalopathy), it is considered to be urgent to develop analytical techniques for distinguishing the geographical origin of beef. Korea is facing conclusion of FTA with many countries, and there is a deep national concern about the distinction of the geographical origin of food. Diverse analytical techniques have been used in many of recent researches to obtain data for distinguishing the geographical origin of foods produced in various countries. In this paper, we reviewed national and international researches about tracing of geographical origin and food authentication using stable isotopes. Improvement of the isotopic techniques and their numerous application have been provided useful information of their geographical origin in food products. Furthermore, we expect that this study could be detecting of many frauds and illegal transaction of food products. We look forward to active progressing research of detecting food origin using isotope analysis and numerous application about imported food products.