• Title/Summary/Keyword: southern sea

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A Newly Recorded Sea Star, Aquilonastra doranae (Asteroidea: Asterinidae), from Jejudo Island, South Korea

  • Taekjun Lee
    • Animal Systematics, Evolution and Diversity
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    • v.39 no.3
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    • pp.127-132
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    • 2023
  • Aquilonastra doranae, a newly recorded sea star, was collected from the southern coast of Jejudo Island by a trimix SCUBA diving survey in May 2021. The newly collected specimen is distinguished from a previously known Aquilonastra species in South Korea by having a fissiparous body form with six arms. Results of pairwise genetic distance analysis showed that the new specimen was identical or close to A. anomala from Hawaii (0.0%), Australia (3.1%), and Samoa (3.3%). However, morphological characteristics of the Korean Aquilonastra specimen corresponded with the original description of A. doranae, not that of A. anomala, including the number of inferomarginal spines, the absence of pedicellariae, and the inhabit locality. Thus, this study agrees with the original morphological study of A. doranae and presents this specimen as the first record of A. doranae in South Korea.

Detection of Urchin Barren Using Airborne Hyperspectral Imagery and SAM Technique - Focusing on the West Sea Island Areas (항공 초분광 영상과 SAM 기법을 이용한 백화현상 탐지 -서해 도서 지역을 중심으로-)

  • Yong-Suk Kim
    • Journal of Environmental Science International
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    • v.33 no.7
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    • pp.533-546
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    • 2024
  • The coastal urchin barren phenomenon in our country began to spread and expand from the 1980s, centering on the southern coast and Jeju Island, and by the 1990s, it appeared along the east coast and nationwide. The urchin barren phenomenon is mainly conducted through field surveys by diving, but recently, various surveying techniques have been applied. In this study, a spectral library for terrestrial and marine areas was established for the identification of urchin barrens using airborne hyperspectral imagery, and the distribution area was analyzed through the SAM (spectral angle mapper) algorithm. An analysis of the urchin barren phenomenon in the five islands of the West Sea revealed that it occurrs in most areas, with the combined severity of the urchin barren phenomenon in Sapsido and Oeyeondo being approximately 19.9%. Hyperspectral imagery is expected to be highly useful not only for detecting the urchin barren phenomenon but also for managing and monitoring marine fishery resources through the classification of seaweeds.

Biomass and Annual Net Production of Quercus Mongolica Stands in Pyungchang and Jecheon Areas (평창 및 제천 지역 신갈나무림의 바이오매스와 연간 순생산량)

  • Lee, Don Koo;Kwon, Ki-Cheol
    • Journal of Korean Society of Forest Science
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    • v.95 no.3
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    • pp.309-315
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    • 2006
  • This study was to compare the biomass and annual net production between 60 to 70-year-old Quercus mongolica stand facing northern and southern aspect in Mt. Joongwang (1000 m from sea level), Pyungchang and 35-year-old Q. mongolica stand in Mt. Wolak (300m from sea level), Jechon. The total biomass was 252.9 ton/ha in northern aspect and 212.2 ton/ha in southern aspect of Mt. Joongwang while 198.7 ton/ha in northern aspect of Mt. Wolak. Annual net production was 17.3 ton/ha/yr in northern aspect and 14.2 ton/ha/yr in southern aspect of Mt. Joongwang while 21.2 ton/halyr in Mt. Wolak. Total biomass, especially leaf and branch biomass in north slope was greater than those in south slope of Mt. Joongwang. Leaf area index (LAI) of Q. mongolica stand was 11.17 in Mt. Wolak while 5.77 in northern aspect and 3.97 in southern aspect of Mt. Joongwang, and the net assimilation rate (NAR) was 2.60 kg/kg/yr, 4.26 kg/kg/yr, 6.06 kg/kg/yr in same order.

A Study on the Ghost Fishing of the Plastic Sea-eel Pot - Investigation of Actual Condition on the Ghost Fishing - (플라스틱 붕장어 통발의 Ghost Fishing에 관한 연구 - Ghost Fishing의 실태조사 -)

  • 정순범;김민석;이주희
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.38 no.1
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    • pp.36-42
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    • 2002
  • This study was conducted to estimate the number of lost or abandoned plastic sea-eel pots and investigate the actual condition on the ghost fishing happened from the pots during the period of August 1996 and January 2002 In the Southern Sea of Korea. The average number of lost or abandoned sea-eel pots in the investigated sea area were 34 ea/$\textrm{km}^2$ and was the lowest as 5 ea/$\textrm{km}^2$ Sea Area code # 113 and was the highest as 94 ea/$\textrm{km}^2$ in the Sea Area code #106. Pots number in accordance with water depth was the highest as 89 ea/$\textrm{km}^2$ on the level of 61 ~70m and there was no collection for the sea-eel pot over 130m water depth. The average catch rate of ghost fishing happened from the lost or abandoned pots was 8.1% and the highest rate was 25% in the Sea Area code #224 and there were no catches in the Sea Area code # 92, 110, 243 and 253. The number of lost or abandoned sea-eel pots continued ghost fishing were estimated as 14.2 ea/$\textrm{km}^2$ in the Sea Area code # 99 and was the highest. Catch rate of ghost fishing according to water depth was the highest as 23.5% on the level of 71~80 m, and the number of lost or abandoned sea-eel pots continued ghost fishing were estimated as 12.7 ea/$\textrm{km}^2$ on the level of 81~90m and was the highest. Length distribution of sea-eel which were caught from ghost fishing was 25.5~66.0$\textrm{cm}^2$

Temporal and spatial Analysis of Sea Surface Temperature and Thermal Fronts in the Korean Seas by Satellite data

  • Yoon Hong-Joo;Byun Hye-Kyung
    • Proceedings of the KSRS Conference
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    • 2004.10a
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    • pp.696-700
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    • 2004
  • In the Korean seas, Sea Surface Temperature (SST) and Thermal Fronts (TF) were analyzed temporally and spatially during 8 years from 1993 to 2000 using NOAA/AVHRR MCSST. As the result of harmonic analysis, distributions of the mean SST were $10~25^{\circ}C,$ and generally SST decreased as latitude increased. SST increased in the order as following; the South Sea $(20\~23^{\circ}C),$ the East Sea $(17\~19^{\circ}C)$, and the West $Sea(13\~16^{\circ}C).$ Annual amplitudes and phases were $4\~11^{\circ}C,\;210\~240^{\circ}$ and high values were shown as following; the West Sea $(A1,\;9\~11^{\circ}C),$ the Northern East Sea $(A5,\;8\~9^{\circ}C),$ the Southern East Sea $(A4,\;6\~8^{\circ}C),$ the South Sea $(A3,\;6\~7^{\circ}C),$ the East China Sea $(A2,\;4\~7^{\circ}C)$ and phases; $A3\;(238\~242^{\circ}),\;A4\;(235\~240^{\circ}),\;A5\;(225\~235^{\circ}),\;Al\;(220\~230^{\circ}),\;A2\;(210\~235^{\circ}),$ respectively, Both of them were related inversely except the area A2, therefore the rest areas were affected by seasonal variations. TF were detected by Soble Edge Detection Method using gradient of SST. Consequently, TF were divided into 4 fronts; the Subpolar Front (SPF) based on the Cold Water Mass (low SST and salinity Subartic Water), resulting from the North Korea Cold Current (NKCC) and the East Sea Proper Cold Water in the middle and low layer, and the Warm Water Mass (high SST and salinity Subtropical Water), resulting from the Tsushima Warm Current (TWC) in area A4 and 5, the Kuroshio Front (KF) based on the Kuroshio Current (KC) and shelf waters in the East China Sea (ESC) in A2, and the South Sea Coastal Front (SSCF) based on the South Sea Coastal Water (SSCW) and TWC in A3. Also, the Tidal Front was weakly appeared in AI. TF located in steep slope of submarine topography. Annual amplitudes and phases were bounded in the same place, and these results should be considered to influence of seasonal variations.

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A Simple Model of the Formation of Thermo-haline Front in the Southeastern Yellow Sea in Winter

  • Seung, Young-Ho;Shin, Sang-Ik
    • Journal of the korean society of oceanography
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    • v.31 no.1
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    • pp.23-31
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    • 1996
  • The thermo-haline front frequently observed near the southwestern tip of Korean Peninsula is successfully modeled using a simple model. The front is formed by the wind-driven advection of local cooled water to the southern warm area which is kept warm by large heat advection of the Tsushima Current. The front thus locates north of the Tsushima Current which runs approximately along the isobaths in the east-west direction.

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Flood Control Measures of the nakdong River Basins (낙동강유역 홍수방지대책 제언)

  • 구본충
    • Journal of the Korean Professional Engineers Association
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    • v.35 no.4
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    • pp.48-51
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    • 2002
  • Due to locally torrential downpours which shows Increasing trend, high tide of the southern sea of Korea and etc. submerged and Inundated districts at the lowlands of Nakdong River Basins has been Increasing year by year In order to protect flood hit, it is necessary to make an early implementation of flood control dam and other flood protection works according to Nakdong River Comprehensive Development Project. In addition to the large scale comprehensive projects, local key measures, such as lowland development control, embankment reinforcement, leakage protection, maintenance and management of facilities, increase in pumping station, will be highly effective.

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El Niño-Southern Oscillation, Indian Ocean Dipole Mode, a Relationship between the Two Phenomena, and Their Impact on the Climate over the Korean Peninsula (엘니뇨-남방진동, 인도양 쌍극자 모드, 두 현상의 관련성, 그리고 한반도 기후에 대한 영향)

  • Cha, Eun-Jeong
    • Journal of the Korean earth science society
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    • v.28 no.1
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    • pp.35-44
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    • 2007
  • This paper investigated the relationship between El $Ni\widetilde{n}o-Southern$ Oscillation (ENSO) and Indian Ocean Dipole (IOD) mode events and the impacts of these two phenomena on the climate, temperature and precipitation, of the Korean Peninsula. Data gathered from 1954 to 2004 were used for analysis, which included NINO 3 index, IOD index, and monthly mean precipitation and temperature at eleven locations in Korea. Statistical results showed that the IOD and ENSO were significantly correlated in Spring and Fall. It was clearly shown that the distribution of the sea surface temperature in the Indian Ocean has seen the Southern and Northern Oscillation in El $Ni\widetilde{n}o$ year, and Eastern and Western in IOD year. On the other hand, in El $Ni\widetilde{n}o$ you, the mean temperature of the Korea Peninsula was lower than normal in Summer and higher in Winter and its precipitation was more than normal in both Summer and Winter. However, significant correlation was not found in IOD year. In addition, the global atmospheric circulations during the major IOD years are less influential, unlike those of El $Ni\widetilde{n}o$ events.

Pacific Sea Level Variability associated with Climate Variability from Altimetry and Sea Level Reconstruction Data (위성 고도계와 해수면 재구성 자료를 이용한 기후변동성에 따른 태평양 해수면 변화)

  • Cha, Sang-Chul;Moon, Jae-Hong
    • Ocean and Polar Research
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    • v.40 no.1
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    • pp.1-13
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    • 2018
  • Previous studies have indicated a great regional difference in Sea Level Rise (SLR) in the Pacific and it has been suggested that this is linked to climate variability over the past two decades. In this study, we seek to identify the possible linkage between regional sea level and Pacific climate variability from altimetry-based sea level data (1993-2012) and further investigate how the Pacific sea level has changed spatially and temporally over the past 60 years from long-term sea level reconstruction data (1953-2008). Based on the same method as Zhang and Church (2012), the Inter-annual Climate Index (ICI) associated with the El $Ni{\tilde{n}}o-Southern$ Oscillation (ENSO) and the Decadal Climate Index (DCI) associated with Pacific Decadal Oscillation (PDO) are defined and then the multiple variable linear regression is used to analyze quantitatively the impact of inter-annual and decadal climate variability on the regional sea levels in the Pacific. During the altimeter period, the ICI that represents ENSO influence on inter-annual time scales strongly impacts in a striking east-west "see-saw mode" on sea levels across the tropical Pacific. On the other hand, the decadal sea level pattern that is linked to the DCI has a broad meridional structure that is roughly symmetric in the equator with its North Pacific expression being similar to the PDO, which largely contributes to a positive SLR trend in the western Pacific and a negative trend in the eastern Pacific over the two most recent decades. Using long-term sea level reconstruction data, we found that the Pacific sea levels have fluctuated in the past over inter-annual and decadal time scales and that strong regional differences are presented. Of particular interest is that the SLR reveals a decadal shift and presents an opposite trend before and after the mid-1980s; i.e., a declining (rising) trend in the western (eastern) Pacific before the mid-1980s, followed by a rising (declining) trend from the mid-1980s onward in the western (eastern) Pacific. This result indicates that the recent SLR patterns revealed from the altimeters have been persistent at least since the mid-1980s.