• 제목/요약/키워드: Seasonal occurrence

검색결과 370건 처리시간 0.032초

제주근해에 출현하는 현생 부유성 유공충 종과 계절변화 (Occurrence of Modern Planktonic Foraminiferal Species and their Seasonal Variations around Jeju Island, Korea)

  • 현상민;카츠노리 키모토;조성환
    • Ocean and Polar Research
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    • 제35권2호
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    • pp.181-191
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    • 2013
  • To investigate the occurrence of modern living planktonic foraminiferal species and their seasonal variations around Jeju Island, we conducted planktonic foraminiferal sampling at KIOST's regular sampling sites during 16 months. In total seven genus and 16 modern planktonic foraminiferal species were identified with six dominant species. Dominant species were Gloigerinoides sacculifer, Globigerinoides ruber, Globigerina bulloides, Noegloboquadrina dutertrei, Pulleniatina obliquiloculata, and Globorotalia inflata. Most of the species were characterized as being typical subtropical species and showed seasonal variations and/or intermittent occurrence from season to season. The occurrence of living foraminifera revealed a strong relationship with water temperature, but not with salinity. Species succession seems to occur along with water temperature changes. Some patch distribution and water temperature dependences appear to be significant since there is a high degree of variation in the occurrence patterns of species and standing stock. More detailed quantitative study is necessary to confirm the species diversity and seasonal variations of planktonic foraminifera and related ocean environmental changes.

Bubble occurrence and interhemispheric plasma transport

  • Park, Jaeheung;Lee, Jae-jin;Lee, Ensang;Min, Kyoung-Wook
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2004년도 한국우주과학회보 제13권1호
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    • pp.72-72
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    • 2004
  • We have compared here the seasonal average of the plasma density with the EPB occurrence in a given longitude sector, using KOMPSAT-1 and DMSP data. It could be evidenced on a global scale that the EPB occurrence was nearly anti-correlated with the poleward drift speed parallel to B-field, and with the degree of asymmetry of the latitudinal plasma distribution. But, the seasonal-longitudinal change of the asymmetry was different from what the current theory expected. (omitted)

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황해 영광 안마 군도 해역의 요각류 출현 양상에 영향을 미치는 계절적 환경 요인 (The Seasonal Environmental Factors Affecting Copepod Community in the Anma Islands of Yeonggwang, Yellow Sea)

  • 정영석;이석주;추서휘;윤양호;조현서;김대진;서호영
    • Ocean and Polar Research
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    • 제45권2호
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    • pp.43-55
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    • 2023
  • This study was conducted to understand the seasonal patterns and variation of the copepod community in the Anma Islands of Yeonggwang, Yellow Sea, with a focus on seasonal surveys to assess the factors affecting their occurrence. Throughout the survey period, Acartia hongi, Paracalanus parvus s. l., and Ditrichocorycaeus affinis were dominant species, while Acartia ohtsukai, Acartia pacifica, Bestiolina coreana, Centropages abdominalis, Labidocera rotunda, Paracalanus sp., Tortanus derjugini, Tortanus forcipatus occurred differently by season and station. As a results of cluster analysis, the copepod communities were distinguished into three distinct groups: spring-winter, summer, and autumn. The results of this study showed that the occurrence patterns of copepod species can vary depending on environmental conditions (topographic, distance from the inshore, etc.), and their spatial occurrence patterns between seasons were controlled by water temperature and prey conditions. One of the physical mechanisms that can affect the distribution of zooplankton in the Yellow Sea is the behavior of the Yellow Sea Bottom Cold Water (YSBCW), which shows remarkable seasonal fluctuations. More detailed further studies are needed for clear grounds for mainly why to many Calanus sinicus in the central region of the Yellow Sea are seasonally moving to the inshore, what strategies to seasonally maintain the population, and support the possibilities of complex factors.

전북지역에 발생하는 진달래방패벌레(노린재목:방패벌레과)의 발생소장 (Seasonal Occurrence of Azalea Lace Bug Stephanitis Pyrioides (Hemiptera: Tingidae) on Chonbuk)

  • 황창연;최선우
    • 한국응용곤충학회지
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    • 제37권1호
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    • pp.49-52
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    • 1998
  • 진달래방패벌레(노린재목: 방패벌레과)의 발생소장을 1994년 전라북도 완주군지역에 식재된 철쭉포장에서 조사하였다. 진달래방패벌레는 전북지역에서 년 최고발생세대수는 4세대였고, 각 세대의 성충발생최성기는 5월 하순, 7월 중순, 8월 하순, 그리고 10월 중순으로 나타났다. 진달래방패벌레는 앞뒷면의 주맥 근처조직에서 알로 월동하였다.

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An Attempt of Estimation of Annual Fog Frequency over Gyeongsangbuk-do of Korea Using Weather Generator MM5

  • Kim, Do-Yong;Oh, Jai-Ho;Kim, Jin-Young;Sen, Pumendranath;Kim, Tae-Kook
    • Environmental Engineering Research
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    • 제14권2호
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    • pp.88-94
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    • 2009
  • In this study an attempt has been made to predict the annual foggy days over Gyeongsangbuk-do of Korea, using the regional mesoscale model (MM5). The annual meteorological conditions are simulated, and the annual and seasonal foggy days are predicted from the simulated results based on the seasonal and spatial information of the observed meteorological characteristics for fog occurrence such as wind speed, relative humidity, and temperature. Most of observed inland fog over Gyeongsangbuk-do occurs in autumn under the meteorological conditions such as a cairn, a high temperature range (above $10^{\circ}C$), and a high relative humidity (above 85%). The predicted results show the various foggy days, about 10${\sim}$60 days, depending on the season and the site locations. The predicted annual foggy days at inland sites are about 30${\sim}$60 days, but at coastal sites, about 10${\sim}$20 days. Also, a higher frequency of fog occurrence at inland sites is shown in autumn (about 60% of the annual foggy days). Otherwise, a higher frequency of fog occurrence at coastal sites is shown in summer (about 60% of the annual foggy days), unlike the inland. These annual foggy days and their seasonal variations agree reasonably well with the observed values. It can be concluded that it is possible to predict the occurrence of annual or seasonal foggy days by MM5.

감나무의 주머니깍지벌레에 대한 발생생태 및 화학적 방제효과 (Seasonal Occurrence and Chemial Control Effects of Eriococcus largerstroemiae Kuwana on Persimmon Trees)

  • 권태영;박소득;박선도;최부술;권용정
    • 한국응용곤충학회지
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    • 제34권4호
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    • pp.295-299
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    • 1995
  • 경북 청도지방 감나무에 기생하는 주요 해충인 주머니깍지벌레에 대한 발생생태 및 방제체계에 대해 1992-1994년에 걸쳐 시험한 결과는 다음과 같다. 일반적으로 주머니각지벌레의 주 월동처는 감나무의 조피속이며 월동후 살아있는 암컷 성충내의 알에 대한 생충율은 28.7%이다. 알에서 부화한 약충은 4월하순경부터 활동하기 시작하여 전 생육기에 걸쳐 부화최성기는 6월하순~7월상순, 8월중.하순, 9월중.하순으로 1년에 3세대를 거치며 7월상순, 8월중순, 9월하순으로 3회의 peak를 이루었다. 암컷성충내의 포란수는 평균 229.3개였으며 주머니깍지벌레의 방제체계 시험에서 결정석회유황합제 + 살충제 2회 97.8%, 기계유유제 + 살충제 2회 96.8% 그리고 생육기간중 살충제 3회 처리는 77.2%의 방제효과를 보였다.

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황해 중동부 해역 동물플랑크톤의 계절적 분포 특성 (Seasonal characteristics of zooplankton community in the Mid-eastern part of the Yellow Sea)

  • 황학진;최중기
    • 한국해양학회지
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    • 제28권1호
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    • pp.24-34
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    • 1993
  • 동물플랑크톤의 계절별 분포 특성을 파악하기 위하여 황해 중동부해역을 대상으로 1987년 4월부터 1988년 6월까지 두달 간격으로 조사를 실시하였다. 이 기간중 총 18속 24종의 동물플랑크톤이 동정 되었게, 이중 12속 17종이 요각류였다. 출현한 동물플랑 크톤중 Noctiluca scintillans가 연안역 정점에서 계절에 따라 전체 동물플랑크톤 군 집에 큰 영향을 미쳤으며, 일부 요각류의 분포를 배제하는 것으로 사료되었다. 동물플 랑크톤 출현양의 30-60.4%를 차지하는 요각류 군집 개체수의 계절별 변화양상은 연안 역 정점이 외해역 정점보다 생태환경의 다양함을 보여주었다. 요각류중 Acartia omorii가 4월과 6월에 Paracalanus parvus가 8월부터 12월까지, Corycaeus affinis가 12월에 각각 우점종으로 출현하였다. 난류 지표중인 Sagitta enflata가 8월부터 12월 까지 조사 해역에 출현하여 본 해역에 대한 난류의야 향을 시사하였으며, 이러한 측면 에서 난수성인 Doliolum sp. 의 10월의 다량 출현도 의미있는 결과였다. 동물플랑크톤 에 대한 종조성 및 양적 분포의 계절적 특성은 수괴의 계절적 변화에 따라 영향을 받 는 것으로 나타났다.

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공급사슬에서 계절적 수요를 고려한 채찍효과 측도의 개발 (Quantifying the Bullwhip Effect in a Supply Chain Considering Seasonal Demand)

  • 조동원;이영해
    • 대한산업공학회지
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    • 제35권3호
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    • pp.203-212
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    • 2009
  • The bullwhip effect refers to the phenomenon where demand variability is amplified when one moves upward a supply chain. In this paper, we exactly quantify the bullwhip effect for cases of seasonal demand processes in a two-echelon supply chain with a single retailer and a single supplier. In most of the previous research, some measures of performance for the bullwhip effect are developed for cases of non-seasonal demand processes. The retailer performs demand forecast with a multiplicative seasonal mixed model by using the minimum mean square error forecasting technique and employs a base stock policy. With the developed bullwhip effect measure, we investigate the impact of seasonal factor on the bullwhip effect. Then, we prove that seasonal factor plays an important role on the occurrence of the bullwhip effect.