• 한국해양학회지:바다
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• 제17권4호
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• pp.225-242
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• 2012

이 연구는 인공위성 고도계로 관측한 해수면 높이 자료를 이용하여 동해 표층해류를 생산하고, 동해 전체 영역에 대하여 동시성 있는 표층해류 분포를 동해 해류 정보 사용자에게 제공하기 위한 최초의 시도이다. 동해 전 영역에서 인공위성 고도계와 연안 조위관측소의 해수면 높이 자료를 동시에 얻을 수 있으므로 준실시간으로 넓은 해역에 대하여 동시성 있는 표층 지형류의 산출이 가능하다. 산출된 동해 표층 지형류로부터 주요 해류의 위치와 세기 그리고 중규모 이상의 소용돌이 발달 양상을 살펴볼 수 있다. 따라서 이들 해류의 이름과 평균적인 위치를 알 수 있도록 동해 해양지명에 대한 명칭과 위치를 기술하고, 개념적인 해류도를 제시하였다. 동해 해류정보가 실제 실용화될 수 있도록 인공위성 고도계 자료를 이용하여 산출한 지형류의 월 계절 연도별 해류 분포 예를 들고, 각 해류 분포를 설명하였다. 또한 시 공간적으로 변화하는 동해 표층해류 분포 형태를 객관적으로 분류하기 위하여 16년(1993~2008년)간의 표층해류 자료를 경험직교함수(Empirical Orthogonal Function, EOF)를 이용하여 분석하였다. EOF분석 제1모드(mode)는 주로 한국 동해안을 따라 북쪽으로 흐르는 동한난류와 야마도분지 남서부 시계방향 순환의 강화 또는 약화를 나타냈다. 제2모드는 동한난류가 동해 남부를 가로지르며 사행하는 정도를 나타냈으며, 해류 사행의 파장은 약 300 km이었다. 제1모드와 제2모드가 모두 해류의 연간 변동성을 나타냈으며, 제1모드와 제2모드의 시간계수에 따라 동해 표층해류 분포를 관성 경계류 패턴(pattern), 대마난류 패턴, 사행 패턴, 외해분지류 패턴으로 분류할 수 있다.

• Ocean and Polar Research
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• 제23권2호
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• pp.161-172
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• 2001

A model-to-model comparison is attempted between Princeton Ocean Model (POM) and Miami Isopycnic Coordinate Ocean Model (MICOM) as a first step to extend our knowledge of models' performances in studying the East Sea circulation. The two models have fundamentally different numerical schemes and boundary conditions imposed on these models are not exactly the same each other. This study indicates that MICOM has a critical weak point in that it does not reproduce the shallow surface currents properly while it handles the thermohaline processes and associated movements of intermediate and deep waters efficiently. It is suggested that the mixed layer scheme needs to be modified so that it can match with inflow boundary conditions in order to reproduce the surface currents properly in MICOM. POM reproduces the surface current pattern better than MICOM, although the surface currents in POM appear to undergo the unrealistic seasonal variation and have exaggeratedly large vertical scale. These defects seem to arise during the process of adapting POM to the East Sea, and removing these defects is left as a future task.

• Journal of information and communication convergence engineering
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• 제2권1호
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• pp.58-60
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• 2004

Sea level variations and sea surface circulations in the Korean seas were observed by Topex/Poseidon altimeter data from 1993 through 1997. In sea level variations, the West and South Sea showed relatively high variations with comparison to the East Sea. Then, the northern and southern area in the West Sea showed the range of 20∼30cm and 18∼24cm, and the northern west of Jeju island and the southern west of Tsushima island in the South Sea showed the range of 15∼20cm and 10∼15cm, respectively. High variations in the West Sea were results to the inflow in sea surface of Yellow Sea Warm Current (YSWC) and bottom topography. Sea level variations in the South Sea were due to two branch currents (Jeju Warm Current and East Korea Warm Current) originated from Kuroshio Current (KC). In sea surface circulations, there existed remarkably three eddies circulations in the East Sea that are mainly connected with North Korea Cold Current (NKCC), East Korea Warm Current (EKWC) and Tushima Warm Current (TWC). Their eddies are caused basically to the influence of currents in sea surface circulations; Cyclone (0.03 cm/see) in the Wonsan bay off shore with NKCC, and anticyclone (0.06 cm/see) in the southwestern area of Ulleung island with EKWC, and cyclone (0.01 cm/see) in the northeastern area of Tushima island with TWC, respectively.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.879-881
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• 2003

Sea level variations and sea surface circulations in the Korean seas were observed by Topex/Poseidon altimeter data from 1993 through 1997. In sea level variations, the West and South Sea showed relatively high variations with comparison to the East Sea. Then, the northern and southern area in the West Sea showed the range of 20${\sim}$30cm and 18${\sim}$24cm, and the northern west of Jeju island and the southern west of Tsushima island in the South Sea showed the range of 15${\sim}$20cm and 10${\sim}$15cm, respectively. High variations in the West Sea was results to the inflow in sea surface of Yellow Sea Warm Current (YSWC) and bottom topography. Sea level variations in the South Sea was due to two branch currents(Jeju Warm Current and East Korea Warm Current) originated from Kuroshio Current (KC). In sea surface circulations, there existed remarkably three eddies circulations in the East Sea that are mainly connected with North Korea Cold Current (NKCC), East Korea Warm Current (EKWC) and Tushima Warm Current(TWC). Their eddies are caused basically to the influence of currents in sea surface circulations; Cyclone (0.03 cm/sec) in the Wonsan bay off shore with NKCC, and anticyclone (0.06 cm/sec) in the southwestern area of Ulleung island with EKWC, and cyclone (0.01 cm/sec) in the northeastern area of Tushima island with TWC, respectively.

• Ocean and Polar Research
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• 제23권2호
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• pp.133-139
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• 2001

Ocean currents estimated from sea height anomalies derived from inter-calibrated TP/ERS are compared with daily mean currents measured with satellite-tracked drifters. The correlation coefficient between the geostrophic current from TP/ERS and surface current at 15 m depth from drifter tracks was found to be about 0.5. Due to the limitation of satellite ground tracks, small scale eddies less than 80 km are poorly resolved from TP/ERS. One of the interesting results of this study is that coastal currents along the eastern coast of Korea were well reproduced from sea height anomalies when the coastal currents were developed in association with eddies near the South Korean coast. The eddy kinetic energy (EKE) estimated from drifters, TP/ERS, and a numerical model are also compared. The EKE estimated from drifters was about 22 % higher than EKE calculated from TP/ERS. The pattern of low EKE level in the northern basin and high EKE level in the southern East Sea is shown in the EKE estimates derived from both the drifters and TP/ERS.

• Ocean Science Journal
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• 제40권2호
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• pp.101-107
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• 2005

A simple analytical model is considered in an attempt to demonstrate a formation mechanism of the abyssal current in the East Sea. In this model, the abyssal currents are driven by wind through an outcrop region and flow along closed geostrophic contours. A rough estimate of the abyssal currents, arrived at by applying this model to the region of deep mixing in the East Sea, gives currents comparable to those observed, although there is an uncertainty in the surface area of the outcrop region. It seems that the spin-up of deep water by wind forcing through the region of deep winter mixing is, at least partly, an important contribution to the formation of the abyssal currents in the East Sea.

• 한국해양환경ㆍ에너지학회지
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• 제18권2호
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• pp.116-122
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• 2015

해면으로부터의 마이크로웨이브 후방산란 시뮬레이션을 이용하여 마이크로웨이브 도플러 레이더에 의한 파고와 해면 흐름 관측법을 평가하였다. 해면으로부터 후방산란하는 마이크로웨이브의 도플러 스펙트럼은 마이크로웨이브 해면 조사폭과 스펙트럼 해석 시간폭의 영향을 받는다. 본 연구에서는 마이크로웨이브 해면 조사폭과 스펙트럼 해석 시간폭의 영향을 조사하기 위하여, 다양한 파랑과 해면 흐름 조건의 수치 해면 생성과 마이크로웨이브 후방산란 시뮬레이션을 통하여 도플러 스펙트럼을 구하였다. 결과에 의하면 마이크로웨이브 해면 조사폭을 파장의 1/5이하, 스펙트럼 해석 시간폭을 파주기의 1/5이하로 설정하면, 충분한 정도의 파고계측이 가능하다. 또한, 파주기에 비해서 충분히 긴 스펙트럼 해석 시간폭을 설정하면 해면 흐름의 상대유속 계측이 가능하다. 시뮬레이션을 이용하여 마이크로웨이브 도플러 레이더에 의한 해면관측의 적절한 계측방법을 찾을 수 있다.

• Ocean and Polar Research
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• 제30권3호
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• pp.313-324
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• 2008

In order to understand the variation of ENSO-related oceanic environments in the tropical and North Pacific Ocean, spatio-temporal variations of sea surface temperature anomaly (SSTA) and sea surface height anomaly (SSHA) are analyzed from distributions of complex empirical orthogonal functions (CEOF). Correlations among warm pool variation, southern oscillation index, and ocean surface currents were also examined with respect to interannual variability of the warm pool in western tropical Pacific. Spatio-temporal distributions of the first CEOF modes for SSTA and SSHA indicate that their variabilities are associated with ENSO events, which have a variance over 30% in the North Pacific. The primary reasons for their variabilities are different; SST is predominantly influenced by the change of barrier layer thickness, while SSH fluctuates with the same phase as propagation of an ENSO episode in the zonal direction. Horizontal boundary of warm pool area, which normally centered around $149^{\circ}E$ in the tropics, seemed to be expanded to the middle and eastern tropical regions by strong zonal currents through the mature phase of an ENSO episode.

• 대한원격탐사학회지
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• 제32권6호
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• pp.589-601
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• 2016

Himawari-8/Advanced Himawari Imager (AHI) 열적외 채널 자료에 Maximum Cross Correlation (MCC), Zero-mean Sum of Absolute Distances (ZSAD), Zero-mean Sum of Squared Distances (ZSSD) 알고리즘을 적용하여 표층 해류를 산출하고, 그 결과를 비교 분석하였다. 각 알고리즘으로 쿠로시오해류 해역의 표층 해류장을 산출한 결과 서로 유사한 양상을 보였다. 오차 발생 비율은 알고리즘에 따른 차이가 거의 나타나지 않았으며, 표층 해류 산출 연산에 소요되는 시간은 ZSAD와 ZSSD 알고리즘이 MCC 알고리즘에 비해 각각 24%, 18% 감소하였다. 산출된 표층 해류는 인공위성 추적 표층 뜰개 자료와 인공위성 고도계 자료로 계산한 표층 해류를 통해 검증하였고, 세 가지 알고리즘의 정확도는 모두 유사한 범위의 값으로 나타났다. 또한 산출된 표층 해류의 정확도는 휘도 온도 수평 구배의 크기와 두 영상 사이의 시간 간격에 의해 영향을 받았다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.352-355
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• 2006

In this study, the seasonal and inter-annual variation of sea surface current in the Gulf of Thailand were revealed through the use of WOD temperature and salinity data and monthly sea surface dynamic heights (SSDH) from TOPEX/Poseidon and ERS-2 altimetry data during 1995-2001. The mean dynamic height and mean geostrohic current were derived from the climatological data while SSDH data gave monthly dynamic heights and their geopstrophic currents. The mean geostrophic current showed strong southward and westward flow of South China Sea water along the gulf entrance. Counterclockwise eddy in the inner gulf and the western side of the gulf entrance associated with upwelling in the area. Seasonal geostrophic currents show basin-wide counterclockwise circulation during the southwest monsoon season and clockwise circulation during the northeast monsoon season. Upwelling was enhanced during the southwest monsoon season. The circulation patterns varied seasonally and inter-annually probably due to the variation in wind regime. And finally we found that congregation, spawning, and migration routes of short-bodied mackerel conform well with coastal upwelling and surface circulation in the gulf.