• 제목/요약/키워드: Naro Island

검색결과 9건 처리시간 0.023초

나로도 주변해역의 수괴 및 어업생물의 계절별 분포특성 (The Seasonal Distribution Characteristics of Watermass and Fishery Creatures in the Adjacent Sea of Naro Island)

  • 박주삼
    • 수산해양교육연구
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    • 제17권1호
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    • pp.132-143
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    • 2005
  • In order to investigate the seasonal variation of watermass and fishery creatures in the adjacent sea of Naro Island, an oceanographic observation was carried out seasonally on the fishing grounds, and the sales performance data of the fisheries cooperative's joint market of Naro Island was examined by using a principal component analysis. The temperature and salinity ranged from 8.1 $^{\circ}C$ to 13.7 $^{\circ}C$ and from 33.1 psu to 34.3 psu in spring, from 14.5 $^{\circ}C$ to 24.2 $^{\circ}C$ and from 30.5 psu to 34.1 psu in summer, from 14.8 $^{\circ}C$ to 18.6 $^{\circ}C$ and from 30.1 psu to 34.0 psu in autumn, and from 4.3 $^{\circ}C$ to 10.1 $^{\circ}C$ and from 33.1 psu to 34.9 psu in winter, respectively. In winter and spring, the offshore water spread out to all sea areas of all water layers. In summer, the mixed waters covered the entire sea surface whereas the mixed water and offshore water covered the bottom. In autumn, the coastal water and mixed water appeared on the surface, but the mixed water was distributed widely on the bottom and the offshore water began to appear in the open sea. For two years from 2002 to 2003, 58 fishery creature species in total were sold in the fisheries cooperative's joint market of Naro Island. In general, the total of 50% fish were sold, and crustacea and mollusc by each 25%. Medium shrimp, whiparm octopus, blue crab, and octopus predominated. A number of species and biomass of fishery creatures were sold mostly in April and May, while they were sold the least in January and February. The seasonal sales results showed that mullet, angler, short necked clam, large shrimp, and webfoot octopus were sold mainly in spring, tonguefish, flathead, pomfret, glass eel, blue crab, whiparm octopus, and squid were sold mainly in summer, and octopus, medium shrimp, and spanish mackerel were sold mainly in autumn.

한국 남해안 여수~통영 연안해역의 멸치 난자치어 분포특성 (Distribution Characteristics of Eggs and Larvae of the Anchovy Engraulis japonica in the Yeosu and Tongyeong Coastal Waters of Korea)

  • 고준철;서영일;김희용;이선길;차형기;김주일
    • 한국어류학회지
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    • 제22권4호
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    • pp.256-266
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    • 2010
  • 2009년 5월부터 8월까지 한국 남해안의 여수~통영 연안역에서 멸치 난자치어 분포특성에 대해 조사하였다. 멸치 난의 밀도는 6월에 가장 높았고, 자치어는 7월에 높게 나타났으며 주 분포해역은 나로도, 남해도 및 사량도 주변해역에서 수온 $19.0{\sim}24.0^{\circ}C$, 염분 33.0~34.4 psu, 용존 산소 6.05~8.13 mg/L, 클로로필 a $1.2{\sim}2.3{\mu}g/L$ 범위에 분포밀도가 높게 나타났다. 수온은 외해역보다 연안역에서 고수온을 나타냈고, 염분은 연안역에서 낮고 외해역에서 높게 나타났으며 연안수의 유입은 조사해역 북쪽의 여자만, 가막만, 광양만 등지에서 유입되고, 외해수의 연안유입은 나로도 및 매물도 남쪽 외해측에서 유입되는 것으로 조사되었다. 여름철 국지적 강우에 따른 다량의 섬진강 하천수 유입은 주변해역의 염분을 감소시키면서 남쪽해역으로 확장되어 산란 및 부화된 난자치어들을 외해역 내지 다른 해역으로 이송시키는 요인으로 판단된다. 발생 초기 난들은 (I~IV) 나로도, 돌산도 및 남해도 주변 해역에 주로 분포한 반면, 발생 후기 난은 (V~IX) 욕지도 및 매물도 주변해역에서 고밀도로 분포하였고, 부화직전 후기 단계의 난과 자치어 대형개체들은 조사해역 동쪽방향으로 갈수록 출현율이 높게 나타났다.

여자만 서수도 해역의 조류 및 조석평균류 특성 (Characteristics of tidal current and mean flow at the west channel of Yeoja Bay in the South Sea of Korea)

  • 추효상
    • 수산해양기술연구
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    • 제55권3호
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    • pp.252-263
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    • 2019
  • In order to understand the tidal current and mean flow at the west channel of Yeoja Bay in the South Sea of Korea, numerical model experiments and vorticity analysis were carried out. The currents flow north at flood and south at ebb respectively and have the reversing form in the west channel. Topographical eddies are found in the surroundings of Dunbyong Island in the east of the channel. The flood currents flow from the waters near Naro Islands through the west channel and the coastal waters near Geumo Islands through the east channel. The ebb currents from the Yeoja Bay flow out along the west and the east channels separately. The south of Nang Island have weak flows because the island is located in the rear of main tidal stream. Currents are converged at ebb and diverged at flood in the northwest of Jeokgum Island. Tidal current ellipses show reversing form in the west channel but a kind of rotational form in the east channel. As the results of tide induced mean flows, cyclonic and anticyclonic topographical eddies at the northern tip but eddies with opposite spin at the southern tip are found in the west channel of Yeoja Bay. The topographical eddies around the islands and narrow channels are created from the vorticity formed at the land shore by the friction between tidal currents and the west channel.

2004년 7월 봇돌바다의 썰물, 전류 및 밀물시 수온과 염분 분포 (Distributions of temperature and salinity in relation to ebb, turn of tide and flood of the Bottol Bada in July, 2004)

  • 최용규;조은섭;이용화;이영식
    • 한국환경과학회지
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    • 제14권2호
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    • pp.167-175
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    • 2005
  • Based on the observation on 20, 23 and 26 July 2004, the distributions of temperature, salinity and stratification was investigated in relation to ebb, turn of tide and flood. The results are as follows: I) The high temperature and low saline water with $23.5\~24.0^{\circ}C\;and\;32.4\~33.0psu$ existed at Naro Island. 2) The cold surface water below $21.0^{\circ}C\;and\;33.0\~33.4psu$ appeared in the area near Gae Island and Geumo Island. 3) The cold and saline water, below $24.0^{\circ}C$ at the surface and $17.0^{\circ}C$ near the bottom, $32.8\~33.8psu$ at the surface and $33.8\~34.0psu$ near the bottom, existed in Sori Island. These waters were more saline compared to the South Sea Coastal Water with about 31.8psu. This suggests that the oceanic saline water intruded into the Bottol Bada through the area near Sori Island. The stratification appeared during all the observation periods due to a high solar radiation of $22MJ/m^2$, and a weak wind speed of 2.9m/s on the average while the mean speed of wind in July is around 3.9 m/s. It qualitatively suggested that the stratification was maintained during the observation periods because of a high solar radiation, a weak wind speed and intrusion of saline oceanic water.

나로도 주변해역의 어장학적 특성 (2) -수괴의계절변화 - (The Characteristics of Fishing Ground in the Adjacent Sea of Naro Island (2) - Seasonal Variation of Watermass -)

  • 김동수;주찬순;박주삼
    • 수산해양기술연구
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    • 제39권1호
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    • pp.19-26
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    • 2003
  • 한국 남해 연안 해역인 나로도 주변 어장에서 동계, 춘계, 하계 및 추계에 조사한 해양 관측 자료를 이용하여, 이 어장에서의 수괴 특성을 분석한 결과를 요약하면 다음과 같다. 1) 나로도 주변 어장에서 수온과 염분의 측정값을 이용한 T-S diagram으로부터 염분을 기준으로 수괴를 구분하였다. 연안수는 30.0∼31.4psu, 혼합수는 31.5∼32.9psu, 외해수 33.0∼35.0psu의 범위로 정하였다. 2) 나로도 주변 어장에 출현하는 동계의 염분 분포범위는 33.1∼34.9psu, 춘계는 33.1∼34.3psu, 하계는 30.5∼34.1psu, 추계는 30.1∼34.0psu의 범위이었다. 3) 나로도 주변 어장에 출현한 연안수, 혼합수 및 외해수의 분포 특성을 계절별로 파악할 수 있었다. 동계와 춘계에는 표층에서 저층까지의 전해역이 외해수로 점유되었다. 하계에는 표층의 전 해역이 혼합수로 점유되지만, 저층에는 혼합수와 외해수로 형성된다. 추계에는 표층에 연안수와 혼합수가 분포하고 있으며, 저층에는 혼합수가 주체를 이루고 있으나 연안역에 국한되어 연안수가 분포하고, 외양으로 외해수가 출현하기 시작한다. 4) 나로도 주변 어장의 수온염분 특성은 계절적으로 변화하여, 동계에는 저온고염의 외해수가 분포하고, 춘계에는 동계의 수괴의 특성을 유지하지만, 수온이 다소 증가한다. 하계에는 고온 저염의 혼합수와 외해수가 분포하고, 추계에는 저온의 연안수, 혼합수 및 외해수가 분포한다. 5) 수온과 염분의 변화가 주로 표층과 20m층 사이에서 이루어져 하계에는 수온이 4.$0\circ_C$/7m의 수직경도를 보였으며, 춘계와 추계에는 수온과 염분의 변화는 적고, 동계에는 연직 혼합이 일어나 상하층간에 균질한 해수가 분포하였다.

Active Exchange of Water and Nutrients between Seawater and Shallow Pore Water in Intertidal Sandflats

  • Hwang, Dong-Woon;Kim, Gue-Buem;Yang, Han-Soeb
    • Ocean Science Journal
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    • 제43권4호
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    • pp.223-232
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    • 2008
  • In order to determine the temporal and spatial variations of nutrient profiles in the shallow pore water columns (upper 30 cm depth) of intertidal sandflats, we measured the salinity and nutrient concentrations in pore water and seawater at various coastal environments along the southern coast of Korea. In the intertidal zone, salinity and nutrient concentrations in pore water showed marked vertical changes with depth, owing to the active exchange between the pore water and overlying seawater, while they are temporally more stable and vertically constant in the sublittoral zone. In some cases, the advective flow of fresh groundwater caused strong vertical gradients of salinity and nutrients in the upper 10 cm depth of surface sediments, indicating the active mixing of the fresher groundwater with overlying seawater. Such upper pore water column profiles clearly signified the temporal fluctuation of lower-salinity and higher-Si seawater intrusion into pore water in an intertidal sandflat near the mouth of an estuary. We also observed a semimonthly fluctuation of pore water nutrients due to spring-neap tide associated recirculation of seawater through the upper sediments. Our study shows that the exchange of water and nutrients between shallow pore water and overlying seawater is most active in the upper 20 cm layer of intertidal sandflats, due to physical forces such as tides, wave set-up, and density-thermal gradient.

나로도 주변해역의 어장학적 특성 (1) - 어장의 해황 변화 - (The Characteristics of Fishing Ground in the Adjacent Sea of Naro Island (1) - Oceanic Condition of Fishing Ground -)

  • 김동수;주찬순;박주삼
    • 수산해양기술연구
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    • 제39권1호
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    • pp.8-18
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    • 2003
  • 한국 남서해 연안 해역인 나로도 주변 어장에서 2000년 동계, 춘계, 하계 및 추계에 조사한 해양 관측 자료를 이용하여 이 어장의 해황 특성을 분석한 결과를 요약하면 다음과 같다. 1) 나로도 주변해역에 출현하는 동계의 수온, 염분 및 클로로필의 분포 범위는 각각 4.3∼10.$\circ_C$, 33.1-34.9psu 0.1-26.2$ug$/$\Omega$ 이었고, 춘계에는 8.1∼13.$7\circ_C$, 33.1∼34.3psu, 0.1-24.4$ug$/$\Omega$이었다. 또한, 하계에는 14.5∼24.$2\circ_C$, 30.5∼34.1psu, 0.1∼30.0$ug$/$\Omega$이었으며, 추계에는 14.8∼18.$6\circ_C$, 30.1∼34.0psu, 0.1∼19.1$ug$/$\Omega$이었다. 2) 수온은 외해보다는 연안에서 더 높았으나, 염분은 연안역에서 낮고 외해에서 높은 정향을 나타내고 있다. 또한, 수온과 염분은 동계와 추계에 연직 혼합을 일으키고, 춘계에는 수평적인 분포를 하며, 하계에는 표층과 중층 사이에 수온 약층과 조밀한 염분 분포를 형성하였다. 3) 클로로필의 분포는 연안수에 의해 공급되는 영양염류의 농도에 크게 지배되고 있는 연안역이 외해역보다 높고, 주로 표층보다는 저층에서 클로로필의 분포가 높게 나타나고 있다. 또한, 동계와 추계에 연직분포를 하고, 춘계와 하계에는 수평적인 분포를 하였다. 4) 연안수의 유엽은 어장의 북쪽으로부터 유입되고 외해수의 연안 유입은 소리도의 남쪽 외해측으로부터 이루어지고 있는 것으로 관측되었다.

Modeling the effects of excess water on soybean growth in converted paddy field in Japan 1. Predicting groundwater level and soil moisture condition - The case of Biwa lake reclamation area

  • Kato, Chihiro;Nakano, Satoshi;Endo, Akira;Sasaki, Choichi;Shiraiwa, Tatsuhiko
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.315-315
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    • 2017
  • In Japan, more than 80 % of soybean growing area is converted fields and excess water is one of the major problems in soybean production. For example, recent study (Yoshifuji et al., 2016) suggested that in the fields of shallow groundwater level (GWL) (< 1m depth), rising GWL even in a short period (e.g. 1 day) causes inhibition of soybean growth. Thus it becomes more and more important to predict GWL and soil moisture in detail. In addition to conventional surface drainage and underdrain, FOEAS (Farm Oriented Enhancing Aquatic System), which is expected to control GWL in fields adequately, has been developed recently. In this study we attempted to predict GWL and soil moisture condition at the converted field with FOEAS in Biwa lake reclamation area, Shiga prefecture, near the center of the main island of Japan. Two dimensional HYDRUS model (Simuinek et al., 1999) based on common Richards' equation, was used for the calculation of soil water movement. The calculation domain was considered to be 10 and 5 meter in horizontal and vertical direction, respectively, with two layers, i.e. 20cm-thick of plowed layer and underlying subsoil layer. The center of main underdrain (10 cm in diameter) was assumed to be 5 meter from the both ends of the domain and 10-60cm depth from the surface in accordance with the field experiment. The hydraulic parameters of the soil was estimated with the digital soil map in "Soil information web viewer" and Agricultural soil-profile physical properties database, Japan (SolphyJ) (Kato and Nishimura, 2016). Hourly rainfall depth and daily potential evapo-transpiration rate data were given as the upper boundary condition (B.C.). For the bottom B.C., constant upward flux, which meant the inflow flux to the field from outside, was given. Seepage face condition was employed for the surrounding of the underdrain. Initial condition was employed as GWL=60cm. Then we compared the simulated and observed results of volumetric water content at depth of 15cm and GWL. While the model described the variation of GWL well, it tended to overestimate the soil moisture through the growing period. Judging from the field condition, and observed data of soil moisture and GWL, consideration of soil structure (e.g. cracks and clods) in determination of soil hydraulic parameters at the plowed layer may improve the simulation results of soil moisture.

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