• 한국환경과학회지
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• 제14권11호
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• pp.1063-1069
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• 2005

2004년 12월 2일부터 8일까지 한국 남해의 표층 부유물질의 분포를 초겨울의 해황과 관련하여 조사하였다. 쓰시마와 제주도를 잇는 지선을 중심으로 전선이 형성되었으며, 이 전선을 중심으로 한국 남해의 연안수와 외양의 쓰시마난류수로 구분되었다. 연안역은 표층에서 저층까지 거의 균일한 수괴 분포를 보였으며, 외양은 성층이 형성되어 있었다. 그리고 부유물질은 연직혼합된 연안역에서는 5.0-6.5 mg/l였으며, 성층이 형성된 외양역은 4.5-5.0 mg/1의 분포를 나타내었다. 초겨울 한국 남해는 표면 냉각 효과와 바람에 의해서 저층의 부유물질이 충분히 재부유할 수 있는 환경이었음을 나타내고 있었다. 또한 관측 기간동안 비록 조류가 비교적 약한 소조기 이었음에도 불구하고 열플럭스에 의한 냉각효과와 바람에 의한 혼합 효과가 강하여 표층과 저층이 혼합하기에 용이하였음을 나타내었다. 이에 따라 수심이 얕은 연안역에서는 저층 퇴적물의 재부유에 의해서 부유 물질이 증가될 수 있음을 시사하고 있었다.

• Ocean and Polar Research
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• 제28권2호
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• pp.209-214
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• 2006

The East Sea Branch (ESB) of KORDI will be launched in 2008. She will take a role of monitoring the sea surface topography and temperature by satellites, short- and long-term sea levels by tide gauges, coastal currents and open-sea circulation by setting up coastal radars and mooring current-meters and acoustic equipments, as well as monitoring nearshore processes, coastal erosion and water pollution. A basic program of coastal zone management will help ocean-policy makers to set up right decisions based upon scientific background of the regional data in the East Sea. Networking among the neighboring countries around the sea will supply more useful information not only for experts but also for ordinary vacationers or fishermen. In order for this program to be successfully settled down during the next decade, it is necessary for a leader to have the right vision to attract more experts from global brain pools and to manage the ESB as a leading-edge observatory in the world. Details about this leading-edge operational program are introduced in the text.

• 대한원격탐사학회지
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• 제33권2호
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• pp.243-248
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• 2017

지구 기후시스템의 중요구성인자인 해빙은 극지방과 고위도에 분포하는 특성상 위성을 통한 탐지가 활발히 수행되고 있다. 위성자료를 이용한 해빙탐지기법은 반사도와 휘도온도자료를 이용하며, 많은 연구에서 휘도온도자료를 통해 산출된 Ice Surface Temperature (IST)를 활용한 기법인 Moderate-Resolution Imaging Spectroradiometer (MODIS)의 해빙탐지기법을 활용하고 있다. 본 연구에서는 IST 산출과정이 생략된 단순하고 효율적인 동적임계값 기법을 활용한 해빙탐지기법을 제시하고자 한다. 동적임계값을 지정하기 위하여 해수의 어는점 이하의 화소를 대상으로 MODIS IST와 MODIS $11{\mu}m$ 채널의 휘도온도, Brightness Temperature Difference ($BTD:T_{11{\mu}m}-T_{12{\mu}m}$)의 상호관계를 분석하였다. 분석 결과, 세수치의 관계가 선형의 특징을 나타내었으며 이를 활용하여 임계값을 지정하였다. 청천역에서 지정한 임계값을 MODIS $11{\mu}m$ 채널에 적용하여 해빙을 탐지하였다. 또한, 본 연구의 해빙탐지기법의 성능을 검증하기 위해 MODIS Sea ice extent를 이용하여 정확도를 분석하였으며 그 결과, Producer Accuracy (PA) 99% 이상의 높은 정확도를 보였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.150-152
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• 2006

The DISCOVER Project (${\underline{D}}istributed$ ${\underline{I}}nformation$ ${\underline{S}}ervices$ for ${\underline{C}}limate$ and ${\underline{O}}cean$ products and ${\underline{V}}isualizations$ for ${\underline{E}}arth$ ${\underline{R}}esearch$) is a NASA funded Earth Science REASoN project that strives to provide highly accurate, carefully calibrated, long-term climate data records and near-real-time ocean products suitable for the most demanding Earth research applications via easy-to-use display and data access tools. A key element of DISCOVER is the merging of data from the multiple sensors on multiple platforms into geophysical data sets consistent in both time and space. The project is a follow-on to the SSM/I Pathfinder and Passive Microwave ESIP projects which pioneered the simultaneous retrieval of sea surface temperature, surface wind speed, columnar water vapor, cloud liquid water content, and rain rate from SSM/I and TMI observations. The ocean products available through DISCOVER are derived from multi-sensor observations combined into daily products and a consistent multi-decadal climate time series. The DISCOVER team has a strong track record in identifying and removing unexpected sources of systematic error in radiometric measurements, including misspecification of SSM/I pointing geometry, the slightly emissive TMI antenna, and problems with the hot calibration source on AMSR-E. This in-depth experience with inter-calibration is absolutely essential for achieving our objective of merging multi-sensor observations into consistent data sets. Extreme care in satellite inter-calibration and commonality of geophysical algorithms is applied to all sensors. This presentation will introduce the DISCOVER products currently available from the web site, http://www.discover-earth.org and provide examples of the scientific application of both the diurnally corrected optimally interpolated global sea surface temperature product and the 4x-daily global microwave water vapor product.

• Ocean and Polar Research
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• 제31권1호
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• pp.11-29
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• 2009

Variability of sea surface temperature (SST) in the Japan/East Sea (JES) was studied using complex empirical orthogonal function (CEOF) analysis. Two daily data sets were analyzed: (1) New Generation 0.05o-gridded SST from Tohoku University, Japan (July 2002-July 2006), and (2) 0.25o-gridded SST from the Japan Meteorological Agency (October 1993-November 2006). Linkages with wind stress curl were revealed using 6-h 1o-gridded surface zonal and meridional winds from ancillary data of the Sea- WiFS Project, a special National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) product (1998-2005). SST anomalies (SSTA) were obtained by removing the seasonal signal, estimated as the leading mode of the CEOF decomposition of the original SST. Leading CEOF modes of residual SSTA obtained from both data sets were consistent with each other and were characterized by annual, semiannual, and quasi-biennial time scales estimated with 95% statistical significance. The Semiannual Mode lagged 2 months behind the increased occurrence of the anticyclonic (AC) wind stress curl over the JES. Links to dynamic processes were investigated by numerical simulations using an oceanic model. The suggested dynamic forcings of SSTA are the inflow of subtropical water into the JES through the Korea Strait, divergence in the surface layer induced by Ekman suction, meridional shifts of the Subarctic Front in the western JES, AC eddy formation, and wind-driven strengthening/weakening of large-scale currents. Events of west-east SSTA movement were identified in July-September. The SSTA moved from the northeastern JES towards the continental coast along the path of the westward branch of the Tsushima Current at a speed consistent with the advective scale.

• 한국지구과학회지
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• 제38권7호
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• pp.469-480
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• 2017

Controversy has surrounded the potential impacts of phytoplankton on the tropical climate, since climate models produce diverse behaviors in terms of the equatorial mean state and El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) amplitude. We explored biophysical impacts on the tropical ocean temperature using an ocean general circulation model coupled to a biogeochemistry model in which chlorophyll can modify solar attenuation and in turn feed back to ocean physics. Compared with a control model run excluding biophysical processes, our model with biogeochemistry showed that subsurface chlorophyll concentrations led to an increase in sea surface temperature (particularly in the western Pacific) via horizontal accumulation of heat contents. In the central Pacific, however, a mild cold anomaly appeared, accompanying the strengthened westward currents. The magnitude and skewness of ENSO were also modulated by biophysical feedbacks resulting from the chlorophyll affecting El $Ni{\tilde{n}}o$ and La $Ni{\tilde{n}}a$ in an asymmetric way. That is, El $Ni{\tilde{n}}o$ conditions were intensified by the higher contribution of the second baroclinic mode to sea surface temperature anomalies, whereas La $Ni{\tilde{n}}a$ conditions were slightly weakened by the absorption of shortwave radiation by phytoplankton. In our model experiments, the intensification of El $Ni{\tilde{n}}o$ was more dominant than the dampening of La $Ni{\tilde{n}}a$, resulting in the amplification of ENSO and higher skewness.

• 대기
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• 제31권3호
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• pp.327-340
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• 2021

In this study, the impact of soil moisture initialization in GloSea5, the operational climate prediction system of the Korea Meteorological Administration (KMA), has been investigated for the period of 1991~2010. To overcome the large uncertainties of soil moisture in the reanalysis, JRA55 reanalysis and CMAP precipitation were used as input of JULES land surface model and produced soil moisture initial field. Overall, both mean and variability were initialized drier and smaller than before, and the changes in the surface temperature and pressure in boreal summer and winter were examined using ensemble prediction data. More realistic soil moisture had a significant impact, especially within 2 months. The decreasing (increasing) soil moisture induced increases (decreases) of temperature and decreases (increases) of sea-level pressure in boreal summer and its impacts were maintained for 3~4 months. During the boreal winter, its effect was less significant than in boreal summer and maintained for about 2 months. On the other hand, the changes of surface temperature were more noticeable in the southern hemisphere, and the relationship between temperature and soil moisture was the same as the boreal summer. It has been noted that the impact of land initialization is more evident in the summer hemispheres, and this is expected to improve the simulation of summer heat wave in the KMA's operational climate prediction system.

• 한국환경과학회지
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• 제17권4호
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• pp.461-468
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• 2008

Competitive power of pelagic fishery in Korea has been weakened by the domestic and international problems such as wage increase and exclusive economic zone. To make it worse, fishing fleet spends more than 80% of fishing time on searching fishing grounds. Real-time information on oceanographic data, temperature in particular, are likely to contribute to raise efficiency of fishing. However, available data obtained by satellite remote sensing, fixed buoy and drifting buoy, limited to sea surface or fixed positions. ARGO (Array for Real-time Geostrophic Oceanography), an international program, has delivered vertical profiles of temperature and salinity in the upper 2000m of the world ocean every 10 days using freely moving floats. We have developed real-time oceanographic information system for pelagic fishery based on the Argo data which has the contents of vertical profile, horizontal distribution and vertical section of temperature around fishing grounds and searched data can be download unrestrictedly. Comparison of skipjack catch with sea surface temperature and depth of $20^{\circ}C$ derived from Argo data in the West Equatorial Pacific revealed that Argo data are able to help fishing fleet to find fishing grounds and to increase catch.

• Ocean and Polar Research
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• 제29권3호
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• pp.193-204
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• 2007

In order to find out the annual variations in the marine ecosystem of the East China Sea, temperature, salinity, nutrients, chlorophyll-a, suspended solids, and suspended particulate organic carbon were extensively investigated in the northern East China Sea during the Summer of 2003 and 2006. During the Summer of 2003, the northern East China Sea was not significantly affected by the input of fresh waters from the Changjiang River. During the Summer of 2006, however, fresh waters of the Changjiang River intruded into the western part of the study area where temperature, nitrate, and phosphate in the surface waters were higher than in the other areas, and salinity, silicate, and suspended solids in the surface waters were lower. As a result of the increase in nitrate and phosphate concentrations, concentrations of chlorophyll-a and suspended particulate organic carbon increased in the western part compared with the other areas. However, the depth-integrated chlorophyll-a concentrations measured during the Summer of 2003 were rather similar to those during the Summer of 2006, and not considerably different from those measured in the East China sea during the Summer of 1994 and 1998. Therefore, the depth-integrated chlorophyll-a concentrations have not significantly changed in the East China Sea over the last 12 years. The lower concentrations of silicate and suspended solids in the western part may be related to construction of the Three-Gorges Dam since the concentrations of silicate and suspended solids in fresh waters of the Changjiang River have significantly decreased after construction of the Three-Gorges Dam in June 2003.

• 대기
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• 제31권2호
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• pp.215-227
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• 2021

The necessity of the prediction on the Seasonal-to-Subseasonal (S2S) timescale continues to rise. It led a series of studies on the S2S prediction models, including the Global Seasonal Forecasting System Version 5 (GloSea5) of the Korea Meteorological Administration. By extending previous studies, the present study documents sea surface temperature (SST) prediction skill around the Korean peninsula in the GloSea5 hindcast over the period of 1991~2010. The overall SST prediction skill is about a week except for the regions where SST is not well captured at the initialized date. This limited prediction skill is partly due to the model mean biases which vary substantially from season to season. When such biases are systematically removed on daily and seasonal time scales the SST prediction skill is improved to 15 days. This improvement is mostly due to the reduced error associated with internal SST variability during model integrations. This result suggests that SST around the Korean peninsula can be reliably predicted with appropriate post-processing.