• 제목/요약/키워드: oceanography

검색결과 2,884건 처리시간 0.029초

Comparison of Chlorophyll Algorithms in the Bohai Sea of China

  • Xiu, Peng;Liu, Yuguang;Rong, Zengrui;Zong, Haibo;Li, Gang;Xing, Xinogang;Cheng, Yongcun
    • Ocean Science Journal
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    • 제42권4호
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    • pp.199-209
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    • 2007
  • Empirical band-ratio algorithms and artificial neural network techniques to retrieve sea surface chlorophyll concentrations were evaluated in the Bohai Sea of China by using an extensive field observation data set. Bohai Sea represents an example of optically complex case II waters with high concentrations of colored dissolved organic mattei (CDOM). The data set includes coincident measurements of radiometric quantities and chlorophyll a concentration (Chl), which were taken on 8 cruises between 2003 and 2005, The data covers a range of variability in Chl in surface waters from 0.3 to 6.5 mg $m^{-3}$. The comparison results showed that these empirical algorithms developed for case I and case II waters can not be applied directly to the Bohai Sea of china, because of significant biases. For example, the mean normalized bias (MNB) for OC4V4 product was 1.85 and the root mean square (RMS) error is 2.26.

Characteristics of Microbial Abundances in Hypoxic Water of Brackish take Shihwa

  • Choi, Dong.H.;Na, Sang.C.;Park, Yong.C.;Huh, Sung.H.;Cho, Byung.C.
    • Journal of the korean society of oceanography
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    • 제34권4호
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    • pp.236-240
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    • 1999
  • A preliminary study was carried out to find characteristics of microbial trophic relations in hypoxic waters of Lake Shihwa in May and August 1996. Abundances of bacteria, viruses, and heterotrophic nanoflagellates (HNF) and HNF grazing on bacteria were measured. Dissolved O$_2$ (DO) saturation ranged from 13 to 34% in the bottom waters, and % of DO saturation strongly correlated with salinity. Ratios of HNF-to-bacteria abundance (42-118${\times}$10$^{-5}$) and biomass (0.06-0.25), and ratios of virus-to-bacteria abundance (110-297) in the hypoxic water were similar to those found in the surface layer, indicating similar structures of microbial abundances and trophic functions in hypoxicand surface waters during the study period. In the hypoxic water, an energy flow from organic matter to bacteria to HNF might operate as equally as in oxic surface layer.

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Management Information System of the Nanji Islands National Marine Reserve, China

  • Qingmei, XIAO;Huaguo, ZHANG;Changbao, ZHOU;Weigen, HUANG;Dongling, LI;Junhua, Ten
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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    • pp.298-300
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    • 2003
  • A management information system of the Nanji Islands National Marine Reserve is designed and constructed based on method of integration of remote sensing and geographic information system (GIS). The system consists of two sub-systems, dynamic monitoring information system and general database system. The former is used for storage and manage fundamental geographical data (topographical and bathymetric map), satellite remote sensing data (IKONOS, SPOT, IRS, NOAA and SeaWiFS etc.) and multimedia data. The latter is used for storage and manage resource data (shellfish and alga etc.), environmental data (meteorological and hydrologic) and in situ data. As part of electronic government, this system will be submitted to local government for monitoring, management and decision.

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Oceanic Pycnocline Depth Estimation from SAR Imagery

  • YANG
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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    • pp.304-306
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    • 2003
  • Oceanic pycnocline depth is usually obtained from in situ measurements. As ocean internal waves occur on and propagate along oceanic pycnocline, it is possible to estimate the depth remotely. This paper presents a method for retrieving pycnocline depth from synthetic aperture radar (SAR) imagery where internal waves are visible. This model is constructed by combining a two-layer ocean model and a nonlinear internal wave model. It is also assumed that the observed groups of internal wave packets on SAR imagery are generated by local semidiurnal tides. Case study in East China Sea shows a good agreement with in situ CTD data.

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Diel Cycles of Nitrogen Uptake by Marine Phytoplankton in NO$_3^-$-high and -low Environments

  • Park, Myung-Gil;Shim, Jae-Hyung;Yang, Sung-Ryull;Lee, Sang-Hoon;Cho, Byung-Cheol
    • Journal of the korean society of oceanography
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    • 제32권4호
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    • pp.191-201
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    • 1997
  • To test the roles of NO$_3^-$ concentration and light as controlling factors of NO$_3^-$ uptake in the NO$_3^-$-low and -high environments and to assess the significance of night-time nitrogen (N) uptake in estimating the daily N uptake rate, 2 diel studies of N uptake were conducted in NO$_3^-$-low (the eastern part of the Yellow Sea) and NO$_3^-$-high (the marginal ice zone of the northwestern Weddell Sea) environments on June 14 to 15, 1996 and January 15 to 16, 1995, respectively. Ourobservations confirmed that NO$_3\;^-$ uptake by phytoplankton is mainly determined by ambient NO$_3^-$ concentration in NO$_3^-$-low environment and by light in NO$_3^-$-high environment, respectively, Our results suggest the need for diel studies to accurately estimate the daily N uptake rates and thus new and regenerated production because the daily rates calculated without considering the night-time N uptake would be significantly underestimated (up to 41%), particularly in the NO$_3^-$-low environment.

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New findings from CREAMS Observations: Water Masses and Eddies in the East Sea

  • Kim, Kuh;Kim, Kyung-Ryul;Kim, Young-Gyu;Cho, Yang-Ki;Chung, Jong-Yul;Choi, Byung-Ho;Byun, Sang-Kyung;Hong, Gi-Hoon;Takematsu, Masaki;Yoon, Jong-Hwan;Volkov, Yuri;Danchenkov, Mikhail
    • Journal of the korean society of oceanography
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    • 제31권4호
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    • pp.155-163
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    • 1996
  • CREAMS (Circulation Research of the East Asian Marginal Seas) is an international research program, which began in 1993 in order to understand the water mass structure and circulation in the East Sea. Since the beginning of CREAMS, there have been four cruises in the summer and two in the winter, covering most parts of the East Sea for the first time in more than 60 years since the historical survey reported by Uda (1934). CREAMS investigations have provided many new insights into the various aspects of oceanographic problems in the East Sea such as water masses, deep sea currents and circulation, eddies, particle fluxes and so on. In this paper, we briefly review understandings before CREAMS and summarize initial new findings from CREAMS expeditions in terms of water masses and currents.

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한국해양학회지에 출판된 화학해양학 분야 연구논문의 서지학적 분석 (Bibliometric Analysis of Scientific Papers on Chemical Oceanography published in the Journal of the Korean Society of Oceanography)

  • 강동진
    • 한국해양학회지:바다
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    • 제24권3호
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    • pp.457-474
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    • 2019
  • 1966년 한국해양학회지가 창간된 이래 2017년까지 약 50 여 년간 영문지인 Ocean Science Journal을 제외하고 약 1,200여 편의 연구 논문이 출판되었다. 이들 중 생물해양학 분야가 37%로 가장 많고, 물리해양학 분야가 25%, 지질해양학분야가 약 17%를 차지한다. 화학해양학에 관한 논문은 약 250편으로 약 20%를 차지한다. 전체 출판된 논문 중 화학해양학 분야는 창간호부터 대체적으로 20% 이상의 수준을 차지하고 있었으나 80년대부터 90년대까지 10%대로 줄어들었다가 1990년대 말 이후 20% 이상을 유지하고 있다. 연구 대상은 연안역에 관한 것이 과반을 차지하였고, 연구 해역은 남해가 1/3을 황해와 동해가 각각 약 1/4에 해당한다. 연구 대상 매체는 해수에 대한 연구가 거의 60%에 육박하고 퇴적물 연구가 약 30%를 차지하였다. 연구 주제는 영양염이 가장 많았고 금속, 동위원소, 환경오염, 유기오염, 유기물, 기체 등의 순을 나타났다. 제1저자의 소속은 대학이 가장 많았으나, 단일 기관으로는 한국해양과학기술원(전신 기관 포함)이 가장 많았다.