한국해 해양열파

장찬주(Chan Joo Jang),최원근(Wonkeun Choi) 한국에너지기후변화학회 2021 한국에너지기후변화학회 학술대회 Vol.2021 No.5

지역기후 접합모델링을 이용한 우리나라 해면수온 미래변화 시범전망

장찬주(Chan Joo Jang),신호정(Ho Jeong Shin),정희석(Hee seok Jung),김철호(Cheol Ho Kim) 한국연안방재학회 2017 한국연안방재학회지 Vol.4 No.1

In spite of an increasing demand on the detailed information on climate change, future climate projections for Korean waters have been conducted very limitedly. Even for the regional climate projections, most of the previous studies used a regional ocean-only model forced by a global model projection result for the atmosphere and thus could not properly simulate the air-sea interactions on a high resolution. The goal of this study is to develop a regional climate coupled model (RCCM) for the Northwest Pacific and present a future climate projection in Korean waters with including high-resolution air-sea interaction effects. In this paper, we present preliminary results focusing on sea surface temperature (SST) changes projected for Korean waters using the RCCM developed for the Northwest Pacific. The RCCM consists of an ocean model, Regional Ocean Modeling System (ROMS) and an atmospheric model, Weather Research Forecast (WRF). The projection results show some prominent features such as a considerable surface warming in the East Sea relative to the Yellow and East China Sea and a stronger warming in summer than in winter. Compared to the ocean-only model result, the RCCM result shows a significant difference in the projected SST, especially in the Yellow Sea, implying that the regional climate modeling allowing air-sea interaction can have a considerable influence on a future climate change projection.

연직혼합모수화가 동해 상층 모사에 미치는 영향

장찬주,임세한,Jang, Chan-Joo,Lim, Se-Han 한국군사과학기술학회 2010 한국군사과학기술학회지 Vol.13 No.6

This study investigates effects of three different parameterizations of vertical mixing scheme on upper ocean simulation of the East Sea, focusing on the seasonal variations of the sea surface temperature(SST) and the mixed layer depth(MLD) using an ocean general circulation model(GFDL MOM1.1). The considered vertical mixing schemes are the Laplacian scheme(L scheme) that use a constant eddy coefficient, the Mellor-Yamada scheme(MY scheme), and a new scheme(Noh scheme). The Noh scheme, a second-order turbulence closure, was developed considering recent observational evidences such as the enhancement of turbulent kinetic energy near the sea surface. During summer L scheme underestimates the SST, while MY scheme overestimates the SST, compared to climatological SST. Noh scheme produces the SST in better agreement with climatological one. During winter all schemes overestimate the SST up to $4^{\circ}C$ compared to climatological SST. Vertical profiles of the basin-mean temperature show that L scheme produces higher temperature below the thermocline than those of other schemes. The winter MLD simulated from L scheme is rather large compared to that from other schemes, but the differences in MLD during summer are not significant.

가을철 대한해협 표면혼합층의 단기변화

장찬주,김구,심태보,Jang, Chan-Joo,Kim, Kuh,Shim, Tae-Bo 한국해양학회 1995 韓國海洋學會誌 Vol.30 No.5

표면혼합층의 단기(2시간~24시간)변화를 조사하기 위하여 대한해협의 한 정점에 서 1983년 10월 12일에서 10월 14일까지 48시간 동안 주로 1시간 간격으로 해양과 기 상에 대한 관측을 실시하였다. 표면혼합층의 깊이와 수온을 시간당 변동률이 평균적으 로 각각 5.2 m/hour, 0.2$^{\circ}C$/hour로 해표면에서의 바람 응력, 부력속과의 상관관계가 매우 적다. 표면 혼합층은 표면혼합층의 수온와 염분이 높을 때 깊고, 낮을 때 얕다. 한편, 표면혼합층 수온의 급격한 하강 또는 상승이 관측되었다. 인공위성 자료와 XBT 자료 분석에 의하면 표면혼합층 수온의 급격한 상승은 고온의 해수의 이류에 의한 일 어남을 알 수 있었다. 위의 결과들은 해류가 비교적 강하고 해수물성이 서로 다른 수 괴가 존재하는 가을철 대한해협에서는 해수의 이류가 표면혼합층의 단기변화에 크게 영향을 준다는 것을 나타낸다.

지구온난화의 지역적 특성: 전례 없는 기후 시기에 대한 선형 전망

신호정,장찬주,SHIN, HO-JEONG,JANG, CHAN JOO 한국해양학회 2016 바다 Vol.21 No.2

Even if an external forcing that will drive a climate change is given uniformly over the globe, the corresponding climate change and the feedbacks by the climate system differ by region. Thus the detection of global warming signal has been made on a regional scale as well as on a global average against the internal variabilities and other noises involved in the climate change. The purpose of this study is to estimate a timing of unprecedented climate due to global warming and to analyze the regional differences in the estimated results. For this purpose, unlike previous studies that used climate simulation data, we used an observational dataset to estimate a magnitude of internal variability and a future temperature change. We calculated a linear trend in surface temperature using a historical temperature record from 1880 to 2014 and a magnitude of internal variability as the largest temperature displacement from the linear trend. A timing of unprecedented climate was defined as the first year when a predicted minimum temperature exceeds the maximum temperature record in a historical data and remains as such since then. Presumed that the linear trend and the maximum displacement will be maintained in the future, an unprecedented climate over the land would come within 200 years from now in the western area of Africa, the low latitudes including India and the southern part of Arabian Peninsula in Eurasia, the high latitudes including Greenland and the mid-western part of Canada in North America, the low latitudes including Amazon in South America, the areas surrounding the Ross Sea in Antarctica, and parts of East Asia including Korean Peninsula. On the other hand, an unprecedented climate would come later after 400 years in the high latitudes of Eurasia including the northern Europe, the middle and southern parts of North America including the U.S.A. and Mexico. For the ocean, an unprecedented climate would come within 200 years over the Indian Ocean, the middle latitudes of the North Atlantic and the South Atlantic, parts of the Southern Ocean, the Antarctic Ross Sea, and parts of the Arctic Sea. In the meantime, an unprecedented climate would come even after thousands of years over some other regions of ocean including the eastern tropical Pacific and the North Pacific middle latitudes where an internal variability is large. In summary, spatial pattern in timing of unprecedented climate are different for each continent. For the ocean, it is highly affected by large internal variability except for the high-latitude regions with a significant warming trend. As such, a timing of an unprecedented climate would not be uniform over the globe but considerably different by region. Our results suggest that it is necessary to consider an internal variability as well as a regional warming rate when planning a climate change mitigation and adaption policy.

선체 고정형 소나의 음영 구역 최소화

임세한,한윤후,장찬주,Lim, Se-Han,Han, Yun-Hoo,Jang, Chan-Joo 한국군사과학기술학회 2010 한국군사과학기술학회지 Vol.13 No.2

This paper introduces the Hull Mounted Sonar Vertical Scanning(HMS Verscan) technique to overcome the limitation of target detection in short range shadow zone. Numerical experiments were done with the HMS Verscan taking advantage of the vertical beamforming technique for two-dimension hydrospace(range-depth). For numerical experiments, ray model and high-frequency monostatic reverberation model were used. HMS Verscan increased a sound pressure level at the short range shadow zone through reflections at the sea surface and seafloor. Inclusion of the boundary scattering improved target detection due to the sound reflected into the shadow zone.

하계 동중국해 북부 해역에서 저층 냉수괴의 거동

장성태,이재학,김철호,장찬주,장영석,Jang, Sung-Tae,Lee, Jae-Hak,Kim, Cheol-Ho,Jang, Chan-Joo,Jang, Young-Suk 한국해양학회 2011 바다 Vol.16 No.1

The Yellow Sea Cold Water (YSCW) is formed by cold and dry wind in the previous winter, and is known to spread southward along the central trough of the Yellow Sea in summer. Water characteristics of the YSCW and its movement in the northern East China Sea (ECS) are investigated by analyzing CTD (conductivity-Temperature-Depth) data collected from summertime hydrographic surveys between 2003 and 2009. By water mass analysis, we newly define the North Western Cold Water (NWCW) as a cold water mass observed in the study area. It is characterized by temperature below $13.2^{\circ}C$, salinity of 32.6~33.7 psu, and density (${\sigma}_t$) of 24.7~25.5. The NWCW appears to flow southward at about a speed less than 2 cm/s according to the geostrophic calculation. The newly defined NWCW shows an interannual variation in the range of temperature and occupied area, which is in close relation with the sea surface temperature (SST) over the Yellow Sea and the East China Sea in the previous winter season. The winter SST is determined by winter air temperature, which shows a high correlation with the winter-mean Arctic Oscillation (AO) index. The negative winter-mean AO causes the low winter SST over the Yellow Sea and the East China Sea, resulting in the summertime expansion and lower temperature of the NWCW in the study area. This study shows a dynamic relation among the winter-mean AO index, SST, and NWCW, which helps to predict the movement of NWCW in the northern ECS in summer.

고해상도 파랑후측에서 나타난 동해 파랑기후의 40년 선형추세

김기호(Kiho Kim),장찬주(Chan Joo Jang) 한국연안방재학회 2020 한국연안방재학회지 Vol.7 No.2

Changes in ocean wave climate play a crucial role in the coastal environments such as coastline change and coastal erosion. In this study, we investigate 99th percentile significant wave heights (SWH) (a measure for extreme SWHs), peak wave period (PWP), and peak wave direction (PWD) in the East Sea, using a 40-year (1979~2018) wave hindcast data simulated from a high-resolution wave model (SWAN) forced with the ERA-Interim wind fields. In association with the substantial seasonality in wind fields by the East Asian monsoon, the long-term means of wave properties (SWH, PWP, PWD) and trend of 99th percentile SWHs appear to significantly differ on the seasonal timescale. In addition, PWP shows an increasing trend in most of the East Sea, except for the northern East Sea during August to October showing a decreasing trend. Our findings suggest that while the PWP tends to increase in most of the East Sea except the northern area from August to October, the long-term trends of the 99th percentile SWH in the East Sea could considerably different depending on regions and seasons.

여름철 황해 동부 연안을 따라 흐르는 연안 경계류: 수치 모델 실험

권경만,최병주,이상호,조양기,장찬주,Kwon, Kyung-Man,Choi, Byoung-Ju,Lee, Sang-Ho,Cho, Yang-Ki,Jang, Chan-Joo 한국해양학회 2011 바다 Vol.16 No.4

Coastal boundary current flows along the eastern boundary of the Yellow Sea and its speed was about 0.l m/s during the summer 2007. In order to find major factors that affect the coastal boundary current in the eastern Yellow Sea, three-dimensional numerical model experiments were performed. The model simulation results were validated against hydrographic and current meter data in the eastern Yellow Sea. The eastern boundary current flows along the bottom front over the upper part of slopping bottom. Strength and position of the current were affected by tides, winds, local river discharge, and solar radiation. Tidal stirring and surface wind mixing were major factors that control the summertime boundary currents along the bottom front. Tidal stirring was essential to generate the bottom temperature front and boundary current. Wind mixing made the boundary current wider and augmented its north-ward transport. Buoyancy forcing from the freshwater input and solar radiation also affected the boundary current but their contributions were minor. Strong (weak) tidal mixing during spring (neap) tides made the northward transport larger (smaller) in the numerical simulations. But offshore position of the eastern boundary current's major axis was not apparently changed by the spring-neap cycle in the mid-eastern Yellow Sea due to strong summer stratification. The mean position of coastal boundary current varied due to variations in the level of wind mixing.

북서태평양 중기해양 예측모형 개발

정희석(Jung, Heeseok),장찬주(Jang, Chan Joo),김용선(Kim, Yong Sun) 한국연안방재학회 2019 한국연안방재학회 학술발표대회 논문집 Vol.2019 No.1

한반도 주변해를 포함한 북서태평양의 해양환경 중기예측을 위하여 지역해양순환모형(ROMS)를 이용해 중기해양 예측모형(Ocean Mid-rAnge prediction System, OMIDAS)을 구축하였다. 수립한 모형의 계절별 3개월 재예측 실험을 수행하였고 그 결과를 이용하여 해면수온 예측 성능을 평가하였다.