• 제목, 요약, 키워드: High tide

검색결과 430건 처리시간 0.031초

제주 연안의 소대망에서 조석에 의한 어획량 변동 (Catch fluctuation of the Pound Set Net According to Tide Age in the Coastal Waters of Jeju)

  • 김병엽;서두옥;이창헌
    • 한국수산과학회지
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    • v.42 no.1
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    • pp.83-88
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    • 2009
  • The purpose of this paper is to obtain the fundamental data on the catch fluctuation in the pound set net according to the tide age from the catch recorded from the year 1997 to 2004 in the coastal waters of Guideok, Jeju. Total catch by the pound set net had a little connection with the tide age. During increasing tide, total catch were reduced slightly from the neap tide to the high tide while there seemed to be a little sign of rise in the total catch until decreasing tide. But in the relation between the catches and the tide age, the level of the correlation coefficient chosen at $p{\le}0.05$ was not significant. Therefore, the catch of the pound set net seemed not to be influenced by the tide age. In addition, CPUE at the high tide was higher than that at the neap tide. When the catch per operating frequency was graded in the order under 50 kg, 50-100 kg and 100-200 kg, the frequency rate by the pound set net was 38%, 19% and 19%, respectively.

서해 근소만에서 영양염의 조석 및 계절 변화 (Tidal and Seasonal Variations of Nutrients in Keunso Bay, the Yellow Sea)

  • 김동선;김경희
    • Ocean and Polar Research
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    • v.30 no.1
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    • pp.1-10
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    • 2008
  • In order to find the effect of intertidal sediments on nutrient cycle in coastal environment, we measured ammonia, nitrate, phosphate, and silicate concentrations every hour during at least 12 hours in the entrance of Keunso Bay during four seasons. The content of ammonia and silicate do not change considerably with season, but nitrate shows large seasonal variation. In summer, nitrate concentration was much lower than in other seasons, which resulted from large biological uptake and active denitrification in intertidal sediments during summer. Phosphate also exhibit seasonal variations, but not that large like nitrate. N/P and N/Si ratios were lower in summer than in other seasons, which was due to active denitrification in the intertidal sediments during summer. For all seasons, ammonia concentrations were higher at low tide than at high tide, but nitrate concentrations were higher at high tide. Dissolved inorganic nitrogen concentrations measured in spring, summer, and winter were higher at high tide than at low tide, but in fall, they were higher at low tide than at high tide. For spring and winter, phosphate and silicate concentrations were higher at low tide than at high tide, while in summer and fall, they were higher at high tide than at low tide. In Keunso Bay, intertidal sediments affect significantly the nutrient cycle around the coastal areas. The intertidal sediments act as a source for ammonia and silicate, but as a sink for nitrate. However, phosphate is not considerably influenced by intertidal sediments.

Satellite Monitoring and Prediction for the Occurrence of the Red Tide in the Middle Coastal Area in the South Sea of Korea

  • Yoon, Hong-Joo;Kim, Young-Seup
    • 대한원격탐사학회지
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    • v.19 no.1
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    • pp.21-30
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    • 2003
  • It was studied the relationship between the red tide occurrence and the meteorological and oceanographic factors, the choice of potential area for red tide occurrence, and the satellite monitoring for red tide. From 1990 through 2001, the red tide continuously appeared and the number of red tide occurrence increased every year. Then, the red tide bloomed during the periods of July and August. An important meteorological factor governing the mechanisms of the increasing in number of red tide occurrence was heavy precipitation. Oceanographic factors of favorable marine environmental conditions for the red tide formation included warm water temperature, low salinity, high suspended solid, low phosphorus, low nitrogen. A common condition for the red tide occurrence was heavy precipitation 2∼4 days earlier, and the favorable conditions for the red tide formation were high air temperature, proper sunshine and light winds for the day in red tide occurrence. From satellite images, it was possible to monitor the spatial distributions and concentrations of red tide. It was founded the potential areas for red tide occurrence in August 2000 by CIS conception: Yeosu∼Dolsan coast, Gamak bay, Namhae coast, Marado coast, Goheung coast, Deukryang bay, respectively.

제주연안 각망의 조석에 의한 어획량 변동 (Catch fluctuation of the rectangular set net according to the tide age in the coastal waters of Jeju)

  • 이창헌;최찬문
    • 수산해양기술연구
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    • v.44 no.2
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    • pp.112-119
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    • 2008
  • The fundamental data on the catch fluctuation in the rectangular set net according to the tide age were developed based on the catches recorded from the year 1986 to 2004 in the coastal waters of Hamdeok, Jeju. Total catch by the rectangular set net had a deep connection with the tide age. In particular, during increasing tide, total catch were reduced gradually from the neap tide to the high tide. As it turned out, the slope of total catch declined by degree and showed a correlation coefficient of determination of 0.76. On the contrary, in the case of decreasing tide, there was little sign of rise in total catch. In particular, large catch seemed to occur at the next tide to the neap tide. In the relation between the catch and the tide age, the level of the correlation coefficient chosen at $p{\leq}0.05$ decreased in the order rabbitfish(-0.84) and horse mackerel(-0.71), while the significance of other dominant species were not selected.

경기만 갯벌의 지표면 토지피복 변화가 국지기상에 미치는 영향 평가 (Impacts of Land Cover Change of Tidal Flats on Local Meteorology in Gyeonggi Bay, West Sea of Korea)

  • 안혜연;김유근;정주희
    • 대기
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    • v.27 no.4
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    • pp.399-409
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    • 2017
  • The impact of land cover changed by tidal flats on local meteorology in Gyeonggi Bay was quantitatively evaluated based on a numerical modeling approach during 18 days (21 June to 9 July 2013). The analysis was carried out using three sets of simulation scenarios and the land cover of tidal flats for each simulation was applied as follows: (1) the herbaceous wetland representing coastal wetlands (i.e., EXP-BASE case), (2) the barren or sparsely vegetated representing low tide (i.e., EXP-LOW case), (3) the water bodies representing high tide (i.e., EXP-HIGH case). The area of tidal flats was calculated as about $552km^2$ (the ratio of 4.7% for analysis domain). During the daytime, the change (e.g. wetlands to water) of land cover flooded by high tide indicated the decrease of temperature (average $3.3^{\circ}C$) and the increase of humidity (average 13%) and wind speed (maximum $2.9m\;s^{-1}$). The changes (e.g. wetlands to barren or sparsely vegetated) of land cover induced by low tide were smaller than those by high tide. On the other hands, the effects of changed land cover at night were not apparent both high tide and low tide. Also, during the high tide, the meteorological change in tidal flats affected the metropolitan area (about 40 km from the tidal flat).

울돌목 수로 동물플랑크톤의 군집 특성 (Characteristics of Zooplankton Community in the Udolmok Waterway, Korea)

  • 유정규;정정호;남은정;명철수
    • 환경생물
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    • v.24 no.2
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    • pp.201-211
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    • 2006
  • 울돌목 수로에서 요각류 35개 분류군을 포함하여 총 55개 동물플랑크톤이 출현하였다. 연안종은 계절적인 종천이를 보였으며, 난류 외양성 종은 전 조사 시기에서 출현하였다. 분류군 수는 창조 시 저조에서 고조로 갈수록 증가하며 낙조 시 고조에서 저조로 갈수록 감소하였다. 따라서 울돌목 해역은 연중 외해수 영향에 따른 외양종의 유입으로 동물플랑크톤 종조성에 영향을 받는다. 전체 동물플랑크톤 현존량은 $104\sim2,717indiv.m^{-3}$의 범위를 나타내며 2003년 8월에 가장 높고 2004년 2월에 가장 낮았다. 조석주기에 따른 현존량 변화에서 11월과 2월에 시간적 변이성이 크고 불규칙적인데 반해 8월과 4월에는 비교적 규칙적인 변화 추세를 나타냈다. 8월과 4월에는 창조 및 낙조에서 조류가 가장 강한 시간에는 낮은 출현 개체수가 나타났으며, 조류가 약해질수록 개체수가 증가하여 고조 및 저조에서 개체수가 높은 특징을 보였다. Paracalanus indicus, Cirripedia nauplii, Acartia hongi등을 포함한 대부분의 우점종은 창조보다 낙조에서 평균 개체수가 대략 2배 정도 높았다. 그러나 창조 및 낙조 내에서도 개체수의 변이가 크게 나타났으며 조석주기에 따른 수온, 염분, 그리고 엽록소 a등 환경변화가 작았다. 따라서 울돌목 해역에서는 강한 조류와 지형적인 조류 속도 차에 의해 형성된 와류 등이 개체군 확산, 이동 그리고 손실에 영향을 미쳐 시간적으로 복잡하고 불규칙한 동물플랑크톤 군집을 보인다.

Meteorological characteristic and satellite monitoring for red tide in the Korean coasts

  • Yoon, Hong-Joo;Kim, Seung-Cheul
    • 대한원격탐사학회:학술대회논문집
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    • pp.873-875
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    • 2003
  • It was studied the relationship between the red tide occurrence and the meteorological factors, and the satellite monitoring for red tide. From 1990 through 2001, the red tide continuously appeared and the number of red tide occurrence increased every year. A common condition for the red tide occurrence was heavy precipitation 2${\sim}$4 days earlier, and the favorable conditions for the red tide formation were high air temperature, proper sunshine and light winds for the day in red tide occurrence. From satellite images, it was possible to monitor the spatial distributions and concentrations of red tide.

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The Coastline Extraction Using RTK GPS/GLONASS

  • Jang, Ho-Sik;Roh, Tae-Ho;Lee, Jong-Chool
    • Korean Journal of Geomatics
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    • v.2 no.2
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    • pp.107-113
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    • 2002
  • On this study, it was applied that the method of Coastline extracting by aerial photogrammetry so as to extract the coastline using the method of RTK GPS/GLONASS. The observed area is Gwanganri beach that is located in Pusan and it was observed according to high wave of scar when the approximate highest high water and it was surveyed according to that the boundary line connecting to sea water surface at random time-zone. Observation analysis was used digital map of 1:1,000 and compared coastline that was converted tide with coastline of high tide. So this conclusions was agreed with converted coastline and high tide coastline.

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천리안 해색위성 GOCI를 이용한 대한민국 남해안 적조 모니터링 (Monitoring Red Tide in South Sea of Korea (SSK) Using the Geostationary Ocean Color Imager (GOCI))

  • 손영백;강윤향;유주형
    • 대한원격탐사학회지
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    • v.28 no.5
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    • pp.531-548
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    • 2012
  • 남해안에서 발생한 Cochlodinium polykrikoides 적조를 적조인 경우와 아닌 경우(satellite high chlorophyll water)로 부터 분류하기 위해서, 본 연구는 Son et al.(2011)의 spectral classification 방법을 세계 최초 해색위성인 GOCI 파장에 맞도록 개선했다. C. polykrikoides 적조인 경우와 아닌 경우는 네 가지 단계를 거쳐서 분리했다. 첫 번째 단계는 적조 발생 가능지역으로 555nm와 680nm (fluorescence peak)에서 피크를 보이는 지역을 선택했다. 두 번째 단계는 적조 발생 가능 지역 중에서 용존유기물/부유물질 함량이 높은 지역과 낮은 지역을 구분했다. 세 번째와 네 번째 단계는 blue-to-green 밴드비를 이용하여 적조 발생 지역과 아닌 지역을 구분했다. 네 가지 단계를 적용한 결과 적조의 스펙트럼은 증가된 식물성 플랑크톤과 용존유기물(부유물질)의 흡광 때문에 짧은 파장에서는 낮은 기울기를 보이고, 증가된 부유물질 때문에 긴 파장에서는 상대적으로 증가된 기울기를 나타냈다. GOCI를 위해 개선된 spectral classification 방법은 C. polykrikoides 적조인 경우와 적조가 아닌 경우에 대해서 높은 user accuracy를 보이고, 다양한 해양환경에서 신뢰성 있는 적조 탐지 가능성을 보이고 클로로필 농도를 이용한 방법이나 기존의 다른 적조 탐지 방법보다 좋은 결과를 보였다. 남해안 C. polykrikoides 적조는 2012년 7월 말에서 8월 초까지 나로도와 통영 부근 해상에서 탐지 되었고, 2012년 8월 중순에는 완도에서 거제도까지 남해안 전체에 걸쳐 발생했다.

Estimation of potential area for red tide occurrence in the Korean coasts by Marine GIS

  • Yoon, Hong-Joo;Whang, Wha-Jeung
    • 대한원격탐사학회:학술대회논문집
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    • pp.876-878
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    • 2003
  • It was studied on the choice of potential area for red tide occurrence from oceanographic factors. Oceanographic factors of favorable marine environmental conditions for the red tide formation included warm water temperature, low salinity, high suspended solid, low phosphorus, low nitrogen. It was founded the potential areas for red tide occurrence in August 2000 by GIS conception: Yeosu~Dolsan coast, Gamak bay, Namhae coast, Marado coast, Goheung coast, Deukryang bay, respectively.

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