• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.13-19
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• 2024

An analysis of the coastal water temperature in the Tongyeong waters, the eastern sea of the South Sea of Korea, revealed that the water temperature rose sharply before the typhoon made landfall. The water temperature rise occurred throughout the entire water column. An analysis of the sea surface temperature data observed by NOAA(National Oceanic and Atmospheric Administration) satellites, indicated that sea water with a temperature of 30℃ existed in the eastern waters of the eastern South Sea of Korea before the typhoon landed. The southeastern sea of Korea is an area where ocean currents prevail from west to east owing to the Tsushima Warm Current. However, an analysis of the satellite data showed that seawater at 30℃ moved from east to west, indicating that it was affected by the Ekman transport caused by the typhoon before landing. In addition, because the eastern waters of the South Sea are not as deep as those of the East Sea, the water temperature of the entire water layer may remain constant owing to vertical mixing caused by the wind. Because the rise in water temperature in each water layer occurred on the same day, the rise in the bottom water temperature can be considered as owing to vertical mixing. Indeed, the southeastern sea of Korea is a sea area where the water temperature can rise rapidly depending on the direction of approach of the typhoon and the location of high temperature formation.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.263-274
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• 2020

In the Southeast Sea of Korea, a cold water mass is formed intensively in summer every year, causing frequent abnormal sea conditions. In order to analyze the spatial changes of sea surface temperature distribution in this area, ocean fields buoy data observed at Gori and Jeongja and reanalyzed sea surface temperature(SST) data from GHRSST Level 4 were used from June to September 2018. The buoy data were used to analyze the time-series water temperature changes at two stations, and the GHRSST data were used to calculate the daily SST variance and weighted mean center(WMC) across the study area. When the buoy's water temperature was lowered, the variance of SST in the study area trend to increase, but it did not appear consistently for the entire period. This is because GHRSST is a reanalysis data that does not reflect sensitive changes in water temperature along the coast. As such, there is a limit to grasping the local small-scale water temperature change in the coast or detecting the location and extent of the cold water zone only by the statistical variance representing the SST change in the entire sea area. Therefore, as a result of using WMC to quantitatively determine the spatial location of the cold water mass, when the cold water zone occurred, WMC was located in the northwest sea area from the mean center(MC) of the study area. This means that it is possible to quantitatively identify where and to what extent the distribution of cold surface water temperature appears through SST's WMC location information, and we could see the possibility of WMC's use in detecting the scale of cold water zones and the extent of regional spread in the future.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.4
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• pp.310-316
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• 2022

Giant pacific octopus, Enteroctopus dofleini, is a large mollusk distributed in the East Sea of Korea. In this study, the catch status of giant pacific octopus by drift line fishery and the effect of sea temperature on fishing ground were investigated in Goseong-gun, Gangwon-do, which is the central coast of the East Sea. The average catch of giant pacific octopus in Gangwon-do was 1,570 tons over the past ten years, and it accounted for 21% in 2008 and 44% in 2021 compared to the total catch in the East Sea during the same period. Such data indicates that the catch in Gangwon-do has recently increased. In this study area, giant pacific octopus weighing 1.1-5.0 kg dominated accounting for 56% of the total individuals, and followed by those weighing 1 kg or less. However, the ratio of catch of giant pacific octopus over 5.1 kg tended to increase in 2021, which is thought to be related to the sea temperature that affected the fishing ground. The main depth of fishing ground was from 21 m to 50 m in this area and fishing grounds were widely distributed throughout the season except summer. Fishing ground was formed with the conditions of bottom sea temperature under 10℃ and was diminished by moving of giant pacific octopus to deeper depth with conditions of bottom sea temperature over 18℃.

• Journal of Environmental Health Sciences
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• v.44 no.3
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• pp.259-266
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• 2018

Objectives: Considered the "national fish" in Korea, the walleye pollock (Gadus chalcogrammus) has disappeared in the East Sea (Sea of Japan), a main habitat and fishing ground for the species. The reason for the disappearance is still a matter of controversy. This study was performed to investigate the long-term relationship between the walleye pollock catch and various meteorological and oceanographic factors in these waters. Methods: Fishery data on walleye pollock and data on meteorological and marine environmental factors over the 30 years (1981-2010) were obtained from the official national database. Time series analysis and correlation and regression analyses were performed to study the relationships. Results: Both air temperature and sea surface temperature in the East Sea rose over these 30 years, and the latter became more prominent. Salinity and dissolved oxygen showed a tendency to decrease while concentrations of nutrients such as nitrite nitrogen and nitrate nitrogen showed an increasing tendency. Sea surface temperature, air temperature, atmospheric pressure, and wind grade were negatively correlated with the catch size of walleye pollock (p<0.05), but salinity was positively correlated (p<0.001). Conclusion: The results of this study indicate that climate change, especially ocean warming, affected the habitat of walleye pollock. The results also indicate that lower sea surface and air temperatures, milder wind grade, and higher salinity were preferred for the survival of the fish species. It is necessary to pay attention to changes of the ocean ecosystem in terms of environmental pollution as well as seawater temperature.

• Journal of Ecology and Environment
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• v.36 no.4
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• pp.217-222
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• 2013

Sea temperature in the South Sea of Korea has been increased over the last decades. Seabirds are sensitive to changes in food availability in marine environment. In this study, we investigate the diet of Black-tailed gulls (Larus crassirostris) during the breeding season to identify changes of marine environment and biological response such as breeding performance in the South Sea of Korea. A total of 22 fish species or family (n = 128) from regurgitates by chicks were collected on Hongdo Island in 2002 and 2012. The most important prey item was Japanese anchovies (Engraulis japonicas). Proportion of Anchovy in diet increased in 2012 (70.5%) compared to 10 years ago (27.5%). Some species were newly found in 2012: Spotted chub mackerel (Scomber australasicus), Pacific sand lace (Ammodytes personatus), White ventral goby (Acanthogobius lactipes), Silver-strip round herring, Multicolorfin rainbowfish (Halichoeres poecilopterus), Silverside (Hypoatherina tsurugae), Surfperch (Neoditrema ransonneti) and Spotnape ponyfish (Leiognathus muchalis), but not in 2002. Especially, sub-tropic fish such as Kammal thryssa (Thryssa kammalensis), and Rosefish (Helicolenus hilgendorfi) were frequently observed in the diet of 2012. These results might reflect the increase of sea temperature in the South Sea of Korea.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.214-218
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• 1999

The aim of our study is to develop new algorism for sea fog detection by using Geostational Meteorological Satellite-5(GMS-5) and suggest the techniques of its continuous detection. So as to detect daytime sea fog/stratus(00UTC, May 10, 1999), visible accumulated histogram method and surface albedo method are used. The characteristic value during daytime showed A(min) > 20％ and DA < 10％ when visble accumulated histogram method was applied. And the sea fog region which detected is of similarity in composite image and surface albedo method. In case of nighttime sea fog(18UTC, May 10, 1999), infrared accumulated histogram method and maximum brightness temperature method are used, respectively. Maximum brightness temperature method(T_max method) detected sea fog better than IR accumulated histogram method. In case of T_max method, when infrared value is larger than T_max, fog is detected, where T_max is an unique value, maximum infrared value in each pixel during one month. Then T_max is beneath 700hpa temperature of GDAPS(Global Data Assimilation and Prediction System). Sea fog region which detected by T_max method was similar to the result of National Oceanic and Atmosheric Administration/Advanced Very High Resolution Radiometer (NOAA/AVHRR) DCD(Dual Channel Difference). But inland visibility and relative humidity didn't always agreed well.

• Journal of the Korean earth science society
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• v.38 no.3
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• pp.182-193
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• 2017

A typical snowfall pattern occurs over the east coastal region of the Korean Peninsula, known as the Yeongdong region. The precipitation over the Yeongdong region is influenced by the cold and dry northeasterly wind which advects over warm and moist sea surface of the East Sea of Korea. This study reveals the influence of large-scale factors, affecting local to remote areas, on the mesoscale snowfall system over the Yeongdong region. The National Centers for Environmental Prediction-Department of Energy reanalysis dataset, Extended Reconstructed sea surface temperature, and observed snowfall data are analyzed to reveal the relationship between February snowfall and large-scale factors from 1981 to 2014. The Yeongdong snowfall is associated with the sea level pressure patterns over the Gaema Plateau and North Pacific near the Bering Sea, which is remotely associated to the sea surface temperature (SST) variability over the North Pacific. It is presented that the relationship between the Yeongdong snowfall and large-scale factors is strengthened after 1999 when the central north Pacific has warm anomalous SST. These enhanced relationships explain the atmospheric patterns of recent strong snowfall years (2010, 2011, and 2014). It is suggested that the newly defined index in this study based on related SST variability can be used for a seasonal predictor of the Yeongdong snowfall with 2-month leading.

• Korean Journal of Remote Sensing
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• v.12 no.1
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• pp.60-80
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• 1996

AVHRR(Advanced Very High Resolution Radiometer) on NOAA satellite provides data in five spectral, one in visible range, one in near infrared and three in thermal range. In this paper, application of NOAA/AVHRR data is studied for environment monitoring such as cloud top temperature, surface temperature, albedo, sea surface temperature, vegetation index, forest fire, flood, snow cover and so on. The analyses for cloud top temperature, surface temperature, albedo, sea surface temperature, vegetation index and forest fire showed reasonable agreement. But monitoring for flood and snow cover was uneasy due to the limitations such as cloud contamination, low spatial resolution. So this research had only simple purpose to identify well-defined waterbody for dynamic monitoring of flood. Based on development of these basic algorithms, we have a plan to further reseach for environment monitoring using AVHRR data.

• The Journal of Fisheries Business Administration
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• v.47 no.4
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• pp.31-44
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• 2016

The purpose of this study is to analyze the climate change exposure of fisheries and fish species in the southern sea of Korea under the RCP climate change scenarios. The extent of exposure was calculated through weighted sum of the sea temperature forecasted by National Institute of Fisheries Science, and the weight were obtained from the time-space distribution of each fisheries or species, based on the micro-data for the fishing information reported by each fisherman. Results show that all the exposed sea temperature of RCP8.5 is higher than that of RCP4.5 in year 2100 as well as in near 2030, therefore it is thought to be very important to reduce the GHG emission even in the short term. The extent of exposure was analyzed to be comparatively high especially in the fisheries such as anchovy drag nets and species like cod, anchovy and squid. Meanwhile the method of this study is considered to be excellent to obtain the accurate extent of exposure under RCP scenarios, and therefore it is applicable on assessing the vulnerability of climate change in fisheries.

• Fisheries and Aquatic Sciences
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• v.10 no.3
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• pp.150-158
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• 2007

Data on squid catches, water temperature, and climatic factors collected for the Northwest and subtropical North Pacific were analyzed to examine the influence of oceanic and climatic conditions in spawning grounds on catches of Japanese common squid, Todarodes pacificus, in the East (Japan) Sea. The main spawning ground was divided into four sub-areas: the South Sea of Korea (R1), the southern waters off Jeju, Korea (R2), the southwestern part of Kyushu, Japan (R3), and the northern part of Okinawa, Japan (R4). Interannual and decadal fluctuations in water temperatures correlated well with squid catches in the East/Japan Sea. In particular, water temperatures at a depth of 50 to 100 m in sub-areas R3 and R4 showed higher correlation coefficients (0.54 to 0.59, p<0.01) in relation to squid catches in the East/Japan Sea than for R1 and R2, which had correlation coefficients of 0.40 or less (p>0.05). Air temperature and wind velocity fluctuations in each sub-area are correlated with water temperature fluctuations and were closely connected with variations in the surface mixed layers. Water, air temperatures and wind velocities at the main spawning grounds are linked to the Southern Oscillation Index (SOI) with higher signals in the ca. 2-4-year band. Strong changes in a specific band and phase occurred around 1976/77 and 1986/87, coincident with changes in squid catches.