• Title/Summary/Keyword: Cheju-do

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Observations of the Cheju Current

  • Suk, Moon-Sik;Pang, Ig-Chan;Teague, William J.;Chang, Kyung-Il
    • Journal of the korean society of oceanography
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    • v.35 no.3
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    • pp.129-152
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    • 2000
  • The Cheju Current (CC), defined here as a mean eastward flow in the Cheju Strait, mostly carries water of high temperature and salinity originating from the Kuroshio in winter and spring, the Cheju Warm Current Water (CWCW). The strong core of the eastward component of the CC is found close to Cheju Island (Cheju-Do, hereafter) in winter and spring with a peak speed of about 17.0 cm/s. The eastward flow weakens towards the northern Cheju Strait, and a weak westward flow occurs occasionally close to the southern coast of Korea. The volume transport ranges from 0.37 to 0.45 Sv(1 Sv=10$^6$ m$^3$/s) in winter and spring. Seasonal thermocline and harocline are formed in summer and eroded in November. The occurrence of the CWCW is confined in the southern Cheju Strait close to Cheju-Do below the seasonal thermocline in summer and fall, and cold water occupies the lower layer north of the CWCW which is thought to be brought into the area from the area west of Cheju-Do along with the CWCW. Stratification acts to increase both the speed of the CC with a peak speed of greater than 30 cm/s and the vertical shear of the along-strait currents. The strong core of the CC detached from the coast of Cheju-Do and shifted to the north during the stratified seasons. The volume transport in summer and fall ranges 0.510.66 Sv, which is about 1.5 times larger than that in winter and spring. An annual cycle of the cross-strait sea level difference shows its maximum in summer and fall and minimum in winter and spring, whose tendency is consistent with the annual variability of the CC and its transport estimated from the ADCP measurements. Moored current measurements west of Cheju-Do indicate the clockwise turning of the CC, and the moored current measurements in the Cheju Strait for 1530 days show the low-frequency variability of the along-strait flow with a period of about 37 days.

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Analysis for Fishing Effort of Diving Women In Cheju-Do (제주 해녀의 어획노력량 분석)

  • CHUNG Sang-Chul
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.22 no.4
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    • pp.196-200
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    • 1989
  • Fishery production of topshell in Cheju-do has been rapidly decreased in the last few years. To investigate the origin of this problem and estimate maximum sustainable yield (MSY) and catch per unit effort (CPUE) of topshell in Cheju-do, a survey has been done ysing the statistical data for 19 years (1968-1986) of topshell production in Cheju-do and data for 3 yea.5 (1984-1986) from an fishery village, Tonggui-ri, Pukcheju-gun, Cheju-do. Maximum sustainable yield of topshell in Cheju-do assumed to be 2,500-2,800 metric tons(M/T) per year. The annual fishery productions of topshell from 1982 to 1986 were 3,368, 3,649, 3,308, 3,136, and 1,400 M/T, respectively. These results show that topshell had been over-fished during 1982 to 1985. Because of the over-fishing, production sharply decreased down to 1,400 M/T in 1986. Total annual production of topshell in Tonggui-ri is a little less than one Percent of that of Cheju-do. To achieve this production, over the half of resistered diving women in this village have been worked. To estimate catch per unit effort of topshell in Cheju-do, it seems better to use the data which is the number of diving women who have been worked for certain period of time than the number of working days in the same period of time.

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Water masses and circulation around Cheju-Do in summer (하계 제주도 주변의 해역 및 해수순환)

  • Kim, Kuh;Rho, Hong-Kil;Lee, Sang-Ho
    • 한국해양학회지
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    • v.26 no.3
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    • pp.262-277
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    • 1991
  • Hydrographic data taken at stations spaced 8-16 nautical miles in the Cheju Strait and the southeastern part of the Yellow Sea in June 1980 and August 1981 show for the first time that oceanic water of high temperature and high salinity exists within 20 km from the northern and western coast of Cheju-Do. It is confirmed that the low salinity trough in the sea around Cheju-Do originates from the river plume on the Yantze Bank. The salinity trough separates the high temperature and high salinity water around Cheju-Do from the surface water of the Yellow Sea and below the seasonal thermocline this distance water meets the Yellow Sea Cold Water forming a thermal front. The Yellow Sea Cold Water seems to spread southward along the Yantze Bank centered at the isobath of 70 m. Its characteristics also appear in the northern part of the Cheju Strait. these complex structures contradict the yellow Sea Warm current suggested by Uda 1934), which is supposed to flow northward into the Yellow Sea along the western coast of Korea. Our data show that dense hydrographic surveys in space and time are prerequisite to understand the circulation around Cheju-Do.

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Higher Fungi of Cheju-do(1) - Unrecorded mushrooms - (제주도의 고등균류(1) - 미기록종 버섯 -)

  • Lee, Jeong-Bae;Oh, Duck-Chul
    • The Korean Journal of Mycology
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    • v.26 no.4 s.87
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    • pp.538-550
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    • 1998
  • The mushrooms of this study were collected mainly on Mt. Halla on Cheju-do from April of 1995 to October of 1997. A total of 292 species from 127 genera were identified. Among them, 103 species from 41 genera of the Basidiomycota and 88 species from 13 genera of the Ascomycota were recorded for the first time on Cheju-do. Five species were recorded for the first time in Korea. They are: Typhula phacorriza, Cordyceps crinalis, Cordyceps cochlidiicola, Cordyceps longissima and Cordyceps prolifica.

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The Mushrooms in Cheju-do -I. The Recorded Mushrooms in Cheju-do- (제주도산(濟州道産)의 버섯 -I. 제주도산(濟州道産)의 기록종(記錄種) 버섯-)

  • Oh, Duck-Chul
    • The Korean Journal of Mycology
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    • v.20 no.4
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    • pp.360-368
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    • 1992
  • Recorded mushrooms in Chju-do, Korea are composed of 1 division, 2 subdivisions, 4 classes, 3 subclasses, 14 orders, 41 families, 96 genera and 186 species. Because of dual recording of synonyms of 5 genera and 16 species, the numbers of genera and species in the list are 101 and 202 respectively.

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Hydrography and Sub-tidal Current in the Cheju Strait in Spring, 1983 (1983년 춘계 제주해협의 해황과 해류)

  • Chang, Kyung-Il;Kim, Kuh;Lee, Suk-Woo;Shim, Tae-Bo
    • 한국해양학회지
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    • v.30 no.3
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    • pp.203-215
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    • 1995
  • Two hydrographic surveys along with direct current measurements using drogues and moored current meters were conducted in Cheju Strait during April and May, 1983. The data clearly demonstrate that a branch of the Kuroshio characterized by high temperature and high salinity enters the Cheju Strait after turning around the western coast of Cheju-Do. The width of the current turning west of Cheju-Do is about 60 km and reduces to 20∼30 km in the strait, resulting in a high speed(>10 cm/s) at the western entrance and in the middle of the strait, compared with a low speed (>5 cm/s) west of Cheju-Do. The Tsushima Current water also originating from the Kuroshio shows its influence in the eastern part of the Cheju Strait. Thermohaline fronts formed between the warm current waters and the coastal waters suggest the southward extension of the Yellow Sea Coastal Water west of the Cheju Strait. A warming of the warm current waters occurs in May, while a cooling takes place in other areas. The major freshening and cooling of water take place in the middle of the Cheju Strait in May due to the intrusion of cold and low salinity water from the west of the Cheju Strait.

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A Revaluation Study of Cheju-Do Solar Insolation Data by Field Measurement (실측에 의한 제주도 일사량자원의 평가)

  • Jo, Dok-Ki;Lee, Tae-Kyu;Chun, Il-Soo;Cho, Suh-Hyun;Auh, Chung-Moo
    • Solar Energy
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    • v.13 no.1
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    • pp.67-74
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    • 1993
  • Solar radiation intensity in Cheju-Do has been measured and analyzed to study the its characteristic and the possibility of the alternative energy, This work will also support the on-going project "Clean Enertopia in Cheju" which is strongly driven by government recently. The results of this project indicate that 1) Insolation in Cheju-Do is 10% lower than Southern coastal area. 2) A significant difference of insolation is observed between western and eastern part of Cheju-Do.

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