• Ocean and Polar Research
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• v.43 no.1
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• pp.15-30
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• 2021

In this study, using 16 ORA-IP (Ocean Reanalysis Intercomparison Project) data, we investigated spatial and temporal changes of net surface heat flux in the East Asian seas and presented a new ensemble net surface heat flux index. The ensemble net surface heat flux index is produced considering the data distribution and the standard deviation of each ORA-IP. From the correlation analysis with air temperature averaged over the Korean Peninsula, ensemble net heat flux around the Korea Strait shows the highest correlation (0.731) with a 3 month time lag. For the correlation study regarding precipitation over the Korean Peninsula, it also shows significant correlation especially in winter and spring seasons. Similar results are also found in comparison with climate indices (AO, PDO, and NINO3.4), but ensemble net surface heat flux data in winter season reveals the strongest correlation patterns especially with winter temperature and spring precipitation.

• Journal of the Korean earth science society
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• v.41 no.4
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• pp.356-366
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• 2020

The accuracy of satellite-observed sea surface salinity (SSS) was evaluated in comparison with in-situ salinity measurements from ARGO floats and buoys in the seas around the Korean Peninsula, the northwest Pacific, and the global ocean. Differences in satellite SSS and in-situ measurements (SSS errors) indicated characteristic dependences on geolocation, sea surface temperature (SST), and other oceanic and atmospheric conditions. Overall, the root-mean-square (rms) errors of non-averaged SMOS SSSs ranged from approximately 0.8-1.08 psu for each in-situ salinity dataset consisting of ARGO measurements and non-ARGO data from CTD and buoy measurements in both local seas and the ocean. All SMOS SSSs exhibited characteristic negative bias errors at a range of -0.50- -0.10 psu in the global ocean and the northwest Pacific, respectively. Both rms and bias errors increased to 1.07 psu and -0.17 psu, respectively, in the East Sea. An analysis of the SSS errors indicated dependence on the latitude, SST, and wind speed. The differences of SMOS-derived SSSs from in-situ salinity data tended to be amplified at high latitudes (40-60°N) and high sea water salinity. Wind speeds contributed to the underestimation of SMOS salinity with negative bias compared with in-situ salinity measurements. Continuous and extensive validation of satellite-observed salinity in the local seas around Korea should be further investigated for proper use.

• Korean Journal of Remote Sensing
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• v.38 no.4
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• pp.355-364
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• 2022

In this study a tendency of abnormal sea surface temperature (SST) occurrence in the seas around South Korea is analyzed from daily SST data from satellite and 14 buoys from August 2020 to July 2021. As thresholds 28℃ and 4℃ are used to determine marine heatwaves(MHWs) and abnormal low water temperature (ALWT), respectively, because those values are adopted by the National Institute of Fisheries Science for the breaking news of abnormal temperature. In order to calculate frequency of abnormal SST occurrence spatially by using satellite SST, research area was divided into six areas of coast and three open seas. ALWT dominantly appeared over a wide area (7,745 km²) in Gyeonggi Bay for total 94 days and it was also confirmed from buoy temperature showing an occurrence number of 47 days. MHWs tended to be high in frequency in the coastal areas of Chungcheongdo and Jeollabukdo and the south coastal areas while in case of buoy temperature Jupo was the place of high frequency (32 days). This difference was supposed to be due to the low accuracy of satellite SST at the coasts. MHWs are also dominant in offshore waters around Korean Peninsula. Although detecting abnormal SST by using satellite SST has advantage of understanding occurrence from a spatial point of view, we also need to perform detection using buoys to increase detection accuracy along the coast.

• Economic and Environmental Geology
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• v.35 no.5
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• pp.437-444
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• 2002

Geomagnetic depth sounding (GDS) was performed to analyze the characteristics of deep resistivity structure in and around the Korean Peninsula. The data that have 0.01 nT precision were collected from 5 geomagnetic observatories and measured every one or five second. In this study, amount of 16 days of geomagnetic data were used for analyzing. Generally the sea affects the GDS data seriously due to its high conductivity. However, though the Korean peninsula is surrounded by seas in three sides, the results given by induction arrow strongly show that the trend of electrical conductivity at neighborhood of the Korean Peninsula is reigned by some geological features. Also it is believed that observation in Jeju island is related with the electrical structure around the East China Sea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.4
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• pp.241-257
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• 2004

Global prognostic models based on NCOM(NCAR CSM Ocean Model) of NCAR which is generic from Bryan-Cox-Semtner model are established to study the ocean circulation in the neighboring seas of Korean peninsula. The model domain covers areas from $80.6{^\circ}S~88.6{^\circ}N$in meridional direction and the vertical water column is divided into 15 levels taking enhanced grid resolution of $0.3^\circ$ around Korean peninsula. Island option is used for 22 islands to simulate inshore circulation by hole-relaxation method and the restart hydrographic data are taken from NCAR(1998) CSM model that has been run for 300 years. The wind stress data are taken from Choi et al. (2002). Based on the model results, circulation patterns in the NW Pacific and global oceans are investigated. Volume transports calculated at five straits in the neighboring seas of Korean peninsula are compared with the results from Choi et al. (2002) and other observed data.

• Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.298-310
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• 2022

Although giant and large fish species are highly important as a keystone species in the marine ecosystem, there have been no or few studies on their spatio-temporal variations around the Korean peninsula. For this, we analyzed daily reports made by observers at 57 fishery landing sites in Korea over 6 years, from 2011 to 2016. In total, 153 fish species were re-identified based on photos and descriptions recorded by Korean observers, of which five species were classified as a giant fish over 5 m in maximum total length (MTL) and 17 species as a large fish from 3 m to 5 m MTL according to the data presented by Froese & Pauly (2021). Among the giant and large fish species, Mola mola was the most abundant species, with 75 individuals landed as by-catch. The second most abundant species was Isurus oxyrinchus (31), followed by Mobula mobular (23), Lamna ditropis (17), Masturus lanceolatus (16), Sphyrna zygaena (14), and Prionace glauca (12). As a result of cluster analysis based on the number of individuals of giant and large fish species by year and sea, six years were separated into two clusters (2011-2013 vs. 2014-2016), with high contribution of M. mola, I. oxyrinchus, and M. lanceolatus; and three seas were separated into two clusters (eastern + southern seas vs. western sea), with high contribution of M. lanceolatus, L. ditropis, and I. oxyrinchus. The largest number of M. mola accounted for 64% of the total in 2014 and 2016, and 71% in summer (June-August). It is assumed to have a correlation between seawater temperature fluctuation and the occurrence of giant and large fish species. Our study highlights importance of longterm monitoring of giant and large fish species, and can help to understand the life cycle such as natal or nursery migration of giant and large fish species around the Korean peninsula.

• Journal of the Korean Geophysical Society
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• v.9 no.3
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• pp.159-169
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• 2006

A GDS (Geomagnetic Depth Sounding) method, one of extremely low-frequency EM methods, has been carried out to examine conductivity anomalies in and around the Korean Peninsula. In this study, new GDS data acquired at the five sites in south-eastern area of the peninsula were incorporated into the previous GDS data. In order to quantitatively interpret observed induction arrows, the 3-D MT modeling considering the surrounding seas of the Korean Peninsula has been performed to evaluate sea effect at each GDS site. The modeling results revealed that the observed real induction arrows were not explained by solely sea effects, consequently two conductive structures that are responsible for the discrepancies between observed and calculated induction arrows were proposed. The first one is the Imjingang Belt, which is thought as an extension of Quiling-Dabie-sulu continental collision belt. The effects of the Imjingang Belt clearly appear at the site YIN and ICHN. The second one is the HCL (Highly Conductive Layer), which is considered as a conductive anomaly by mantle upwelling produced in back-basin region. The effects of the HCL are seen at the site KZU, KMT101, and KMT 107 in the south-eastern region of the Korean Peninsula.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.227-230
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• 1999

Surface solar radiation over the sea is estimated using Visible and Infrared Spin Scan Radiometer data onbord Geostationary Meteorological Satellite(GMS) 5 for January, 1997 to December 1997 in clear and cloudy conditions. The hourly insolation is estimated with a spatial resolution of 5$\times$ 5 km grid. The island pyranometer belonging to the Japan Meteorological Agency is used for validation of the estimated insolation. It is shown that the estimated hourly insolation has RMSE(root mean square) error of 104 W/$m^2$. The variability of the hourly solar radiation was investigated on 3 areas over seas around Korean Peninsula. The solar radiation of East Sea is similar to Yellow Sea. The maximum value of solar radiation is on June of year. The maximum value in south sea is on August because weather is poor by low pressure and front in June

• Atmosphere
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• v.18 no.2
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• pp.147-158
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• 2008

Domestic IOP (intensive observing period) has mostly been represented by the KEOP (Korea Enhanced Observing Period), which started the 5-yr second phase in 2006 after the first phase (2001-2005). During the first phase, the KEOP had focused on special observations (e.g., frontal systems, typhoons, etc.) around the Haenam supersite, while extended observations have been attempted from the second phase, e.g., mountain and downstream meteorology in 2006 and heavy rainfall in the mid-central region and marine meteorology in 2007. So far the KEOP has collected some useful data for severe weather systems in Korea, which are very important in understanding the development mechanisms of disastrous weather systems moving into or developing in Korea. In the future, intensive observations should be made for all characteristic weather systems in Korea including the easterly in the central-eastern coastal areas, the orographically-developed systems around mountains, the heavy snowfall in the western coastal areas, the upstream/downstream effect around major mountain ranges, and the heavy rainfall in the mid-central region. Enhancing observations over the seas around the Korean Peninsula is utmost important to improve forecast accuracy on the weather systems moving into Korea through the seas. Observations of sand dust storm in the domestic and the source regions are also essential. Such various IOPs should serve as important components of international field campaign such as THORPEX (THe Observing system Research and Predictability EXperiment) through active international collaborations.

• Atmosphere
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• v.31 no.3
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• pp.283-294
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• 2021

An Observing System Experiment (OSE) using Global Ocean Data Assimilation and Prediction System (GODAPS) was conducted to evaluate the assimilation impact of Argo floats, deployed by National Institute of Meteorological Sciences/Korea Meteorological Administration (NIMS/KMA), in marginal seas around Korean peninsula. A data denial experiment was run by removing Argo floats in the Yellow Sea and the East Sea from an operational run. The assimilation results show that Argo floats bring the positive impact on the analysis of ocean internal structure in both Yellow Sea and East Sea. In the East Sea, overall positive impact in the water temperature and salinity context is found, especially outstanding improvement from 300 to 500 m depth. In the Yellow sea, the assimilation impact on water temperature and salinity is also large within 50 m depth, especially greater impact than the East Sea in salinity. However, in the Yellow Sea, the influence of Argo floats tends to be restricted to the vicinity of Argo floats, because there was only one Argo float in the middle of the Yellow Sea during the experiment period. Given that the only limited number of Argo floats generally contribute in a positive way to the improvement of the GODAPS, further progress could be expected with adding more observations from Argo floats to current observing systems.