• Proceedings of the KSRS Conference
• /
• 2006.03a
• /
• pp.95-100
• /
• 2006

Measurements of ocean color from space since 1970s provided vital information with reference to physical and biogeochemical properties of the oceanic waters. The utility of these data has been explored in order to map and monitor highly toxic/or harmful algal blooms (HABs) that affected most of coastal waters throughout the world due to accelerated eutrophication from human activities and certain oceanic processes. However, the global atmospheric correction and bio-optical algorithms developed for oceanic waters were found to yield false information about the HABs in coastal waters. The present study aimed to evaluate the potential use of red tide index (RI) method, which has been developed by Ahn and Shanmugam (2005), for mapping of HABs in Korean and neighboring waters. Here we employed the SSMM to remove the atmospheric effect in the SeaWiFS image data and the achieved indices by RI method were found more appropriate in correctly identifying potential areas of the encountered HABs in Korean South Sea (KSS) and Chinese coastal waters during 1999-2004. But the existence of high absorbing and scattering materials greatly interfered with the standard OC4 algorithm which falsely identified red tides in these waters. In comparison with other methods, the RI approach for the early detection of HABs can provide state managers with accurate identification of the extent and location of these blooms as a management tool.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 1997.04a
• /
• pp.80-80
• /
• 1997

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.3
• /
• pp.405-411
• /
• 2020

Recently, studies on underwater communication, related to the development of underwater resources, disaster monitoring and defense, have been actively carried out. In the design of wireless communication systems, path loss is the most important information to derive a link budget that is required to guarantee communication reliability by calculating received power level for the given communication link. The underwater acoustic channel have different characteristics according to geographical location and relevant environmental factors such as water temperature, depth, wave height, algae, and turbidity. Subsequently, many research institutes aiming to develop underwater acoustic communication systems are researching actively on the underwater acoustic channels in various sea areas. In Korea, however, studies on the path loss of the acoustic channel are still insufficient. Therefore, in this study, the path loss of the acoustic channel are studied based on measurement data of the at-sea experiment conducted at Geohae-do, southern sea of Korea.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 1999.11a
• /
• pp.454-457
• /
• 1999

Most of oceanic information are related with spatial properties directly or impliedly and Presented differently depend on applications. So, without efficient integrated data model and strategies it inevitably occurs redundant development results of database itself and application systems. Therefor to avoid these inefficiencies it is most basic need to establish the ocean data infrastructure based on unified data model. In this paper we suggest the guideline for object data model based on ocean GIS concept followed with a sample primitive object data model implementing tile proposed guideline. With this unified data model we could expect the improvement ill the every phase of ocean related environment from data acquisition through translation and utilizing to service and exchange.

• Korean Journal of Remote Sensing
• /
• v.27 no.6
• /
• pp.663-675
• /
• 2011

Sea Surface Temperatures (SSTs) using the equations of NOAA (National Oceanic and Atmospheric Administration) / NESDIS (National Environmental Satellite, Data, and Information Service) were validated over the seas around Korea with satellite-tracked drifter data. A total 1,070 of matchups between satellite data and drifter data were acquired for the period of 2009. The mean rms errors of Multi- Channel SSTs (MCSSTs) and Non-Linear SSTs (NLSSTs) were evaluated to, in most of the cases, less than $1^{\circ}C$. However, the errors revealed dependencies on atmospheric and oceanic conditions. For the most part, SSTs were underestimated in winter and spring, whereas overestimated in summer. In addition to the seasonal characteristics, the errors also presented the effect of atmospheric moist that satellite SSTs were estimated considerably low ($-1.8^{\circ}C$) under extremely dry condition ($T_{11{\mu}m}-T_{12{\mu}m}$ < $0.3^{\circ}C$), whereas the tendency was reversed under moist condition. Wind forcings induced that SSTs tended to be higher for daytime data than in-situ measurements but lower for nighttime data, particularly in the range of low wind speeds. These characteristics imply that the validation of satellite SSTs should be continuously conducted for diverse regional applications.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.30 no.6
• /
• pp.997-1004
• /
• 1997

The effect of the oceanic condition on variations of the catches of Alaska pollack (Theragra chalcogramma) in the East Sea (the Japan Sea) is examined using monthly catches data of this fish and temperature data during 1972 to 1991. Since 1973 the catches of Alaska pollack have gradually increased, showing a peak in 1981, and then rapidly decreased after 1986. A significant negative correlation was found between variations of the catches and the temperature at 50 m depth offshore Mukho. In 1981, the year of the highest catches in the study period, the water mass in the Eastern Korean Coastal Sea of the East Sea was extremely cold, while the year of poor catch, 1979, was much warmer than the annual mean temperature. The results show that the temperature variations around the Eastern Korean Coastal Sea play an important role in the variations of the catches of Alaska pollack, implying that the effect of the Tsushima Warm Current is also very important.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2010.05a
• /
• pp.550-553
• /
• 2010

미국해양대기국(NOAA : National Oceanic and Atmospheric Administration) 위성에 의해서 해수표면 수온자료를 실시간으로 제공하며, 이를 이용하여 우리나라는 한국해양자료센터(KODC : Korea Oceanographic Data Center)에서 해양과학정보를 수집 관리하여 연근해 어민 및 수산관련기관에 배포하고 있다. 그러나 원양어업을 하고 있는 선박에서는 통신요금의 문제로 제대로 제공받지 못하고 있다. 본 논문은 이를 해결하고자 수온정보 이미지의 변환, 압축을 통한 통신요금 절감 및 컬러 이미지 제공에 따른 판별력 향상에 도움을 주고자 한다.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.5 no.2
• /
• pp.47-53
• /
• 2002

Ocean surface wind speed was estimated using TRMM (Tropical Rainfall Measurement Mission) TMI (TRMM Microwave/Imager) data. It is used the TRMM TMI brightness temperature and National Data Buoy Center's buoy winds speed dataset near North-America to estimate by the algorithm of the ocean surface wind speed retrieval over North America. Comparing with the buoy data by D-matrix equation, the result that RMSE, BIAS, and correlation coefficient are 2.19 $ms^{-1}$, 1.10 $ms^{-1}$, and 0.81, respectively. Therefore the estimated oceanic surface wind speed by TRMM TMI brightness temperature data show that available to ocean research over upper ocean.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.304-306
• /
• 2003

Oceanic pycnocline depth is usually obtained from in situ measurements. As ocean internal waves occur on and propagate along oceanic pycnocline, it is possible to estimate the depth remotely. This paper presents a method for retrieving pycnocline depth from synthetic aperture radar (SAR) imagery where internal waves are visible. This model is constructed by combining a two-layer ocean model and a nonlinear internal wave model. It is also assumed that the observed groups of internal wave packets on SAR imagery are generated by local semidiurnal tides. Case study in East China Sea shows a good agreement with in situ CTD data.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.36 no.4
• /
• pp.417-429
• /
• 2003

Abnormal oceanic conditions associated with the passage of typhoons are examined using hydrographic and satellite data 1990-2002. During the passage period of typhoons in the Korean waters, an abrupt decrease of sea surface temperature (SST) in range of 5 to $8^{\circ}C$ was observed. The areas of SST decrease were an order of 100-200 km, and the low SST lasted about 15-25 days after passage of typhoon. After passage of typhoon, the water temperatures in the surface mixed layer of 30 m show negative anomalies for quite a long period. In addition, stratification parameters were substantially decreased and chlorophyll a density was rapidly increased.