• 제목/요약/키워드: Seasonal and interannual variation

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The Seasonal and Interannual Variability of the Volume Transport through the Western Channel of the Korea Strait

  • Kim, Young-Ju;Takikawa, Tetsutaro;An, Hui-Soo;Yoon, Jong-Hwan
    • Journal of the korean society of oceanography
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    • 제39권3호
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    • pp.155-162
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    • 2004
  • The variation of volume transport during the period from 1965 to 2000 through the western channel of the Korea Strait was estimated by obtaining an relation function between the ADCP volume transport and the geostrophic volume transport estimated by the sea level difference between Pusan and Izuhara. The estimated climatological mean volume transport during past 36 years has seasonal variation with a minimum of 1.15 Sv in February and a maximum of 1.88 Sv in October. The mean volume transport for 36 years is 1.51 Sv. The annual mean volume transport has an interannual variation with a minimum of 1.26 Sv in 1968 and maximum of 1.90 Sv in 1973, with three dominant periods of variations of 14.96 years, 4.96 years and 2.99 years.

고리 주변해역 통발에서 채집된 십각류 종조성의 계절변동과 연간변동 (Seasonal and Interannual Variation in Species Composition and Abundance of Decapod Assemblages Collected using Pots in the Coastal Waters off Gori, Korea)

  • 허성회;박주면;정달상;백근욱
    • 한국수산과학회지
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    • 제43권5호
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    • pp.503-509
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    • 2010
  • The seasonal and interannual variation in the species composition and abundance of the decapod assemblage (shrimps, crabs, and hermit crabs) collected using pots in the coastal waters off Gori were studied between 2005 and 2008. During the study period, 49 decapod species belonging to 19 families were collected. The dominant species were Crangon hakodatei, Pandalus gracilis, Carcinoplax longimana, Charybdis bimaculata, Carcinoplax vestita, Diogenes edwardsii, and Dardanus arrosor. These seven species accounted for 95.46% of the total number of individuals collected. The number of species, number of individuals, biomass, and species diversity indices fluctuated with the seasons. The peak number and biomass of individuals occurred in July 2006. The number and biomass of individuals were higher in summer and lower in winter, and the diversity indices were lower in summer than in the other seasons. The abundance of dominant species showed some seasonal and interannual change; in particular, those of C. hakodatei and P. gracilis corresponded with the bottom water temperature.

동해 남부 연안해역 통발에서 채집된 어류 군집의 계절변동과 연간변동 (Seasonal and Interannual Variation in Species Composition of Fish Assemblages Collected by Pots in the Southern Coast of East Sea, Korea)

  • 박주면;허성회
    • 한국어류학회지
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    • 제27권4호
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    • pp.310-316
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    • 2015
  • 본 연구는 동해 남부 연안해역 통발에서 채집된 어류 종조성의 계절 및 연간변동을 조사하였다. 어류 시료는 2005년에서 2008년까지 계절별로 채집하였다. 조사기간 동안 24과에 속하는 32종의 어류가 채집되었다. 우점종은 붕장어 (Conger myriaster), 미역치 (Paracentropogon rubripinnis), 꼼치 (Liparis tanakae), 쌍동가리 (Parapercis sexfasciata), 먹장어 (Eptatretus burgeri), 청어 (Clupea pallasii pallasii)였으며, 이들 6종은 총채집개체수의 91.9%를 차지하였다. 어류 군집의 출현종수, 개체수, 생체량, 다양도는 계절변동을 나타내었는데, 출현종수와 개체수는 2008년 8월에 가장 높았고, 생체량과 다양도는 2005년 8월에 가장 높았다. ANOSIM 분석 결과, 2008년 어류 종조성은 다른 년도와 유의한 차이를 나타내었다. 반면 계절별 채집 종조성은 유의한 차이를 보이지 않았다.

동해 재분석 자료에 나타난 북한한류의 계절 및 경년변동성 (Seasonal and Interannual Variability of the North Korean Cold Current in the East Sea Reanalysis Data)

  • 김영호;민홍식
    • Ocean and Polar Research
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    • 제30권1호
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    • pp.21-31
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    • 2008
  • Analyzing the results of East Sea Regional Ocean Model using a 3-dimensional variational data assimilation scheme, we investigated spatial and temporal variability of the North Korean Cold Current (NKCC) in the East Sea. The climatological monthly mean transport of the NKCC clearly shows seasonal variation of the NKCC within the range of about 0.35 Sv ($=0^6m^3/s$), which increases from its minimum (about 0.45 Sv) through December-January to March, decreases during March and May, and then increases again to the maximum (about 0.8 Sv) in August-September. The volume transport of the NKCC shows interannual variation of the NKCC with the range of about 1.0 Sv that is larger than seasonal variation. The southward current of the NKCC appears often not only in summer but in winter as well. The width of the NKCC is about 35 km near the Korean coast and its core is located under the East Korea Warm Current. The North Korean Cold Water (NKCW), characterized by low salinity and low temperature, is located both under the Tsushima Warm Water and in the western side of the maximum southward current of the NKCC that means the NKCC advects the NKCW southward along the Korean coast. It is revealed that the intermediate low salinity water, formed off the Vladivostok in winter, flows southward to the south of $37^{\circ}N$ through $2{\sim}3$ paths; one path along the Korean coast, another one along $132^{\circ}E$, and the middle path along $130^{\circ}E$. The path of the intermediate low salinity varies with years. The reanalysis fields suggest that the NKCW is advected through the paths along the Korean coast and along $130^{\circ}E$.

남한 지역에서 발생한 구름-지면 낙뢰의 극성별 특성 (Characteristics by the Cloud-to-Ground Lightning Polarity Occurred over South Korea)

  • 명지수;서명석
    • 한국지구과학회지
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    • 제31권4호
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    • pp.335-347
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    • 2010
  • 이 연구에서는 기상청에서 관측한 최근 7년(2002-2008)간의 낙뢰자료를 이용하여 남한지역에서 발생한 구름-지면 낙뢰 현상의 극성별 시 공간적 특성을 분석하였다. 낙뢰빈도는 극성에 관계없이 강한 경년변동, 계절변동 및 일 변동을 보이고 있다. 낙뢰빈도는 여름과 겨울에 각각 최대(74%) 및 최소(0.6%)를 보이고 있다. 또한 계절과 극성에 따라 다르지만 낙뢰는 평균적으로 새벽과 오후에 최대로 발생하는 일 변동을 보이고 있다. 정극성 비율(정극성/부극성)은 여름에 7.3%로 낮으나 겨울에는 62.5%로 강한 계절 변동을 보이고 있다. 낙뢰강도는 경년 및 일 변동은 거의 보이지 않고 있으며 낙뢰가 많이 발생하는 여름에 약하고 낙뢰가 적게 발생하는 겨울에 강한 계절 변동을 보이고 있다. 또한 정극성 낙뢰강도는 강한 계절 변동을 보이는 반면 부극성은 상대적으로 약한 계절 변동을 보이고 있다. 낙뢰밀도는 영동과 동해 지역보다 서부 내륙 및 서 남해상에서 높게 나타나고 있다. 낙뢰강도의 경우 극성에 관계없이 내륙에서보다 바다, 특히 동해상에서 강하게 나타나고 있다.

북반구 하부성층권 극기온의 경년변화와 수십년주기변화의 수치모의 (A Numerical Simulation of the Interannual and Decadal Variations of the Northern Lower Stratospheric Polar Temperature)

  • 최우갑;김유진;김동준
    • 대기
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    • 제19권1호
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    • pp.79-91
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    • 2009
  • Seoul National University General Circulation Model (SNUGCM) has been run for 100 years to obtain daily temperature and meridional velocity at the Northern lower stratosphere. The model results are compared with the NCEP/NCAR reanalysis data. The polar temperature and the eddy heat flux from the model show that the model-produced climatology has well-known cold bias and weaker planetary wave activities. The model climatology also has a lag in the seasonal evolution. The relationship between the model-produced polar temperature and the eddy heat flux is investigated with respect to the interannual and decadal time scales. The interannual variation of the polar temperature is related with both total and stationary eddy heat flux in January and March, which is in agreement with observation. The model, however, does not reproduce the relationship between the decadal variation of the polar temperature and transient eddy heat flux, which is revealed in the observed data.

북서태평양의 표층엽록소 변동성 (Variability of Surface Chlorophyll Concentration in the Northwest Pacific Ocean)

  • 박지수;석문식;윤석;유신재
    • Ocean and Polar Research
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    • 제30권3호
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    • pp.277-287
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    • 2008
  • We collected information on seasonal and interannual variability of surface chlorophyll a concentration between 1997-2007 from the Northwest Pacific Ocean. Satellite data were used to acquire chlorophyll a and sea surface temperature from six regions: East Sea/Ulleung Basin, East China Sea, Philippin Sea, Warm Pool region, Warm Pool North region, and Warm Pool East region. Mixed layer depth (MLD) was calculated from temperature profiles of ARGO floats data in four of the six regions during 2002-2007. In the East Sea/Ulleung Basin, seasonal variability of chlorophyll a concentration was attributed to seasonal change of MLD, while there was no significant relationship between chlorophyll a concentration and MLD in the Warm Pool region. Interannual anomaly in sea surface temperature were similar among the East Sea, East China Sea, Philippin Sea, and Warm Pool North region. The anomaly pattern was reversed in the Warm Pool East region. However, the anomaly pattern in the Warm Pool region was intermediate of the two patterns. In relation to chlorophyll a, there was a reversed interannual anomaly pattern between Warm Pool North and Warm Pool East, while the anomaly pattern in the Warm Pool region was similar to that of Warm Pool North except for the El $Ni\tilde{n}o$ years (1997/1998, 2002/2003, 2006/2007). However, there was no distinct relationship among other seas. Interestingly, in the Warm Pool and Warm Pool East regions, sea surface temperature showed a pronounced inverse pattern with chlorophyll a. This indicates a strong interrelationship among sea surface temperature-MLD-chlorophyll a in the regions. In the Warm Pool and Warm Pool East, zonal distribution of chlorophyll a concentration within the past 10 years has shown a good relationship with sea surface temperature which reflects ENSO variability.

동해 북서해역의 표층해황 특성 (On the Characteristics of the Oceanic Condition in the Surface Layer of the Northwestern East Sea (Japan Sea))

  • 김철호
    • 한국해안해양공학회지
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    • 제8권2호
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    • pp.215-220
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    • 1996
  • 동한만을 중심으로 한 동해 북서해역의 계절별 및 연별 표층해황 특성을 고찰하였다. 동한만의 계절별 해황은 춘계에 동한난류수의 세력이 우세하다가 하리에 북한한류의 강화와 더불어 냉수역이 발달하는 형과, 봄부터 냉수의 세력이 탁월하다가 여름이 되면서 동한난류수의 영향을 받는 형의 두가지 유형을 보인다. 경년변동 특성도 동한난류와 북한한류간의 흐름의 상대적 세기와 유로에 따라 4가지 유형으로 분류된다. 각각의 경우, 동한만 부근에는 대ㆍ소규모의 저기압성 냉수과 혹은 고기압성 난수과가 발달하는 것이 한 특징이다.

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대기 대순환 모헝과 해수면 온도 관측 자료를 이용한 태풍 활동의 계절 예측 가능성 (Seasonal Predictability of Typhoon Activity Using an Atmospheric General Circulation Model and Observed Sea Surface Temperature Data)

  • 한지영;백종진
    • 한국지구과학회지
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    • 제27권6호
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    • pp.653-658
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    • 2006
  • 대기 대순환 모형인 GCPS를 이용하여 북서태평양에서의 태풍 활동의 계절 예측 가능성을 조사하였다. 1979년부터 2003년까지 각 해에 대해 해수면 온도 관측 자료를 사용하여 5개월간 초기 조건을 달리한 10개의 앙상블 멤버를 적분하였다. 모형은 발생 빈도의 평균적인 월변화 경향과 발생 분포를 관측과 유사하게 모의하였으나, 발생 빈도의 경년 변화는 신빙성 있게 예측하지 못하였다. 이는 관측과 모형간 태풍 발생 빈도와 ENSO의 상관성 차이에 인한 것으로 실제 태풍 발생 빈도와 ENSO가 뚜렷한 상관 관계를 갖지 않는 것과 달리, 모형에서는 엘니뇨 시기에 평년에 비해 많은 태풍이 발생하고 라니냐 시기에 평년에 비해 적은 태풍이 발생하는 경향을 보였기 때문이다. 반면에, 관측과 모형 모두 ENSO와의 상관 관계가 높게 나타난 태풍 발생 경도의 경우에는 모형이 발생 경도의 경년 변화를 관측과 유사하게 모의하였다.

부산 기장 연안에서 저인망으로 어획된 어류 군집의 계절 변화 (Seasonal Variation of Species Composition of fish by Otter Trawl in the Coastal Waters off Gijang, Busan, Korea)

  • 황철희;박윤정
    • 한국수산과학회지
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    • 제50권4호
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    • pp.429-436
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    • 2017
  • The seasonal and interannual variations in fish assemblages in the coastal waters off Gijang were examined with an otter trawl from 2015 to 2016. A total of 59 fish species was collected during the study period. The dominant species were Caelorinchus multispinulosus, Clupea pallasii pallasii and Chelidonichthys spinosus. Seasonal changes in fish assemblages appeared to be distinct in the study area. The fish assemblages in summer and autumn were clearly distinguishable from those in other seasons, and the largest numbers of species and individuals were captured in winter and summer, respectively. Because fish assemblages are closely related to changes in water temperature, long-term changes in water temperature can have a significant impact on the productivity of offshore fisheries by changing fish species composition, habitat migration, and growth rate of fish.