• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.3
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• pp.328-333
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• 2019

During the winter of 2017/2018, significantly low water temperatures were detected around the western and southern coasts of Korea (WSCK). In this period, sea surface temperature (SST) in the Korea Waters was about $2^{\circ}C$ lower than mean temperature. Using the real-time observation system, we analyzed the temporal variation of SST during this period around the western and southern coasts. Low water temperature usually manifested over a period of about 10 ~ 20 days. The daily Arctic oscillation index was also similarly detectable with the variation of SST. From the cross-correlation function, we compared two periodic variations, which were SST around the WSCK and the Arctic oscillation index. The cross correlation coefficients between both variations were approximately 0.3 ~ 0.4. The time lag of the two time series was about 6 to 7 days. Therefore, significantly low water temperatures during winter in the Korean coastal areas usually became detectable 6 to 7 days after the negative peak of Arctic oscillation.

• Ocean and Polar Research
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• v.23 no.1
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• pp.51-62
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• 2001

The Arctic consists of numerous sedimentary basins containing voluminous natural resources and two of the world's major oil and gas producing areas. The western Siberia Basin in the Arctic region has the largest petroliferous province with an area of 800 ${\times}$ 1,200 km and produces more than 60% of total Russian oil production. The North Slope of Alaska produces about 20% of the U.S. output, i.e., 11% of the total U.S. consumption. Being small compared to those regions, the Canadian Northwest Territories and the Pechora Basin in Russia produce only fair amount of oil and natural gas. There are also many promising areas in the northern continental shelf of Russia. In addition to Russia, Svalbard and Greenland have been investigated for oil and gas. Gas hydrates are widespread in both permafrost regions and arctic continental shelf areas. The reserves of gas hydrates in the Arctic Ocean are about 20${\sim}$32% of total estimated amounts of gas hydrates in the world ocean. Mineral mining is well developed, especially in Russia. The major centers are located around the Kuznetsk Basin and Noril'sk. They are major suppliers of gold, tin, nickel, copper, platinum, cobalt, iron ore, coal as well as apatite. There are also some minings of lead-zinc in Alaska and Arctic Canada.

• Ocean and Polar Research
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• v.45 no.2
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• pp.89-102
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• 2023

Climate and environmental changes in the Arctic Ocean due to global warming have been linked to extreme climate change in mid-latitude regions, including the Korean Peninsula, requiring a better understanding of the Arctic climate system based on the paleo-analog. This review introduces three paleoenvironmental research cases using neodymium isotopes (¹⁴³Nd/¹⁴⁴Nd, ε_Nd) measured on two different fractions of marine sediments: silicate-bound 'detrital' and Fe-Mn oxide-dominated 'authigenic' fractions. In the first case, detrital ε_Nd in core HH17-1085-GC on the continental shelf off northern Svalbard was used for tracing changes in sediment provenance and associated glacier behavior over the last 16.3 ka. The second case showed the potential use of authigenic ε_Nd as a quasi-conservative water mass tracer. Three prominent ε_Nd peaks and troughs observed in core PS72/410-1 from the Mendeleev Ridge in the western Arctic Ocean over the past 76 ka suggested episodic meltwater discharge events during 51~46, 39~35 and 21~13 ka BP. The last case proposed the use of the difference between authigenic and detrital ε_Nd as a proxy for reconstructing glacier fluctuation. The idea is based on the assumption that enhanced glacial erosion during glacier advances can supply sufficient freshly-exposed rock substrate for incongruent weathering, potentially leading to greater isotopic decoupling between bedrock and dissolved weathering products as recorded in detrital and authigenic ε_Nd, respectively. Thus, it would be worthwhile to take advantage of sedimentary ε_Nd to improve our understanding of past environmental changes in polar regions.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.2
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• pp.45-55
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• 2017

Long chain alkyl diols (LCDs) have been reported in sediments from various marine environments. Rampen et al. (2012) introduced the paleo-sea surface temperature (SST) proxy, Long chain Diol Index (LDI) based on the relative abundance of $C_{30}$ 1,15-diol, $C_{28}$ 1,13-diol, and $C_{30}$ 1,13-diol. In general, CP-Sil5CB and DB-5ms columns have been used for the quantitative and qualitative analysis of LCDs with a GC-MS. In this study, we examined the effect of three different columns (CP-Sil5CB, HP-5ms and DB-5) on the quantitative analysis of LCDs using marine sediments from the East Sea of Korea and the western Arctic Ocean. In general, our study showed that the results of CP-Sil5CB differed significantly from those of HP-5ms and DB-5. However, the differences of the LDI-derived SSTs among three columns were $0.1-0.2^{\circ}C$ for the East Sea and $0.2-0.7^{\circ}C$ for the western Arctic Ocean, which were well within the calibration error range (${\pm}1{\sigma}$). Accordingly, our study showed that the use of different columns resulted in significant differences of LCDs concentrations, but its effect on the LDI was relatively insignificant. Therefore, it appears that the different columns can be used for the paleo-SST reconstruction in the East Sea and the western Arctic Ocean using the LDI proxy.

• Proceedings of the KSRS Conference
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• v.2
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• pp.1019-1022
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• 2006

Satellite sea ice data from 1978 to the present reveal that the perennial ice (or ice that survives the summer) has been rapidly declining at almost 10% per decade. Warming due to increases in greenhouse gases in the atmosphere is now also being reflected in winter with drastic reductions in the maximum extent observed in 2005 and 2006. The retreat of the perennial ice also exposes more open water and has revealed an asymmetric distribution of chlorophyll a pigment concentration in the Arctic basin. Phytoplankton blooms are most dominant at high latitudes, partly on account of sea ice, but in the Arctic basin, it appears that pigment concentrations in the Eastern (Laptev Sea) Region are on the average three times higher than those in the Western (Beaufort Sea) Region. Such asymmetry suggests that despite favorable conditions provided by the melt of sea ice, there are other factors that affects the productivity of the region. The asymmetry is likely associated with much wider shelf areas in the East than in the West, with sea ice processes that inhibits the availability of nutrients near the surface in deep water regions, and river run-off that affects nutrient availability. The primary productivity in the pan-Arctic region have been estimated using the pigment concentrations and PAR derived from SeaWiFS data and the results show large seasonal as well as interannual variability during the 1998 to 2005 period. The data points towards increasing productivity for later years but with only 9 years of data it is too early to tell the overall effect of the sea ice retreat.

• Proceedings of the Korean Quaternary Association Conference
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• 2004.11a
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• pp.37-43
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• 2004

The response of the CCCma coupled climate model to the imposition of LGM conditions is investigated. The global mean SAT and SST decrease by about $10^{\circ}C$ and $5.6^{\circ}C$ in the coupled model. Tropical SST decreases by $6.5^{\circ}C$, whereas CLIMAP reconstructions suggest that the tropics cool by only about $1.7^{\circ}C$, although the larger tropical cooling is consistent with the more recent proxy estimates. With the incorporation of a full ocean component, the coupled model gives a realistic spatial SST pattern, capturing features associated with ocean dynamics that are seen in the CLIMAP reconstructions. The larger decrease of the surface temperature in the model is associated with a reduction in global precipitation rate (about 15%). The tropical Pacific warm pool retreats to the west and a mean La $Ni\tilde{n}a$-like response is simulated with less precipitation over the central Pacific and more in the western tropical Pacific. The more arid ocean climate in the LGM results in an increase in SSS almost everywhere. This is particularly the case in the Arctic Ocean where large SSS increase is due to a decrease in river discharge to the Arctic Ocean associated with the accumulation of snow over the ice sheet, but in the North Atlantic by contrast SSS decreases markedly. This remarkable reduction of SSS in the North Atlantic is attributed to an increase in fresh water supply by an increase in discharges from the Mississippi and Amazon rivers and an increase in P-E over the North Atlantic ocean itself. The discharges increase in association with the wetter LGM climate south of the Laurentide ice sheet and in South America. The fresh water capping of the northern North Atlantic results in a marked reduction of deep convection and consequently a marked weakening of the North Atlantic overturning circulation. In the LGM, the maximum overturning stream function associated with the NADW formation decreases by about 60% relative to the control run, while in the Southern Ocean, oceanic convection is stronger in the LGM due to reduced stratification associated with an increase in SSS and a decrease in SST and the overturning stream function associated with the formation of AABW and the outflow increases substantially.

• Journal of Ship and Ocean Technology
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• v.12 no.1
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• pp.35-44
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• 2008

As arctic energy resource is attracting public attention, arctic shipping market will also be growing in large as expected to increase in LNG trade from Arctic area to the western countries by shipping. During the voyages through such routes, collision with icebergs may be possible. In the present report, ice collision analyses are carried out from a practical point of view to verify the safety of hull structural strength of LNG carriers equipped with GTT $MKIII^{TM}$ membrane type cargo containment system. From the results of collision analyses and the operation-friendly design concept of no-repairing of cargo containment system, a safe operating envelope against ice collision is proposed for LNG carriers of membrane type cargo containment system. Based on the currently proposed safety criteria, it is concluded that LNG carriers with membrane tank type can operate safely with regard to the integrity of CCS in regions where collision between LNG carrier and iceberg is expected.

• Journal of the Korean earth science society
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• v.28 no.5
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• pp.545-555
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• 2007

Ocean general circulation model developed by GFDL on the basis of MOM4 of FMS are examined and evaluated in order to elucidate the global ocean status. The model employs a tripolar grid system to resolve the Arctic Ocean without polar filtering. The meridional resolution gradually increases from $1/3^{\circ}$ at the equator to $1^{\circ}$ at $30^{\circ}N(S)$. Other horizontal grids have the constant $1^{\circ}$ and vertical grids with 50 levels. The ocean is also coupled to the GFDL sea ice model. It considers tidal effects along with fresh water and chlorophyll concentration. This model is integrated for a 100 year duration with 96 cpu forced by German OMIP and CORE dataset. Levitus, WOA01 climatology, serial CTD observations, WOCE and Argo data are all used for model validation. General features of the world ocean circulation are well simulated except for the western boundary and coastal region where strong advection or fresh water flux are dominant. However, we can find that information concerning chlorophyll and sea ice, newly applied to MOM4 as surface boundary condition, can be used to reduce a model bias near the equatorial and North Pacific ocean.

• Korean Journal of Mineralogy and Petrology
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• v.34 no.1
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• pp.15-29
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• 2021

In the Arctic Ocean, the distribution of sea ice and ice sheets changes as climate changes. Because the distribution of ice cover influences the mineral composition of marine sediments, studying marine sediments transported by sea ice or iceberg is very important to understand the global climate change. This study analyzes marine sediment samples collected from the Arctic Ocean and infers the provenance of the sediments to reconstruct the paleoenvironment changes of the western Arctic. The analyzed samples include four gravity cores collected from the Araon mound in the Chukchi Plateau and one gravity core collected from the slope between the Araon mounds. The core sediments were brown, gray, and greenish gray, each of which corresponds to the characteristic color of sediments deposited during the interglacial/glacial cycle in the western Arctic Ocean. We divide the core sediments into three units based on the analysis of bulk mineral composition, clay mineral composition, and Ice Rafted Debris (IRD) as well as comparison with previous study results. Unit 3 sediments, deposited during the last glacial maximum, were transported by sea ice and currents after the sediments of the Kolyma and Indigirka Rivers were deposited on the continental shelf of the East Siberian Sea. Unit 2 sediments, deposited during the deglacial period, were from the Kolyma and Indigirka Rivers flowing into the East Siberian Sea as well as from the Mackenzie River and the Canadian Archipelago flowing into the Beaufort Sea. Unit 2 sediments also contained an extensive amount of IRD, which originated from the melted Laurentide Ice Sheet. During the interglacial stage, fine-grained sediments of Unit 1 were transported by sea ice and currents from Northern Canada and the East Siberian Sea, but coarse-grained sediments were derived by sea ice from the Canadian Archipelago.

• Ocean and Polar Research
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• v.40 no.3
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• pp.127-143
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• 2018

This study analyzed the influence of climate change on the spawning ground area of the common squid, Todarodes pacificus. To estimate long term changes in the area of the spawning ground of the common squid, water temperature at 50 m deep that can be inferred from sea surface temperature (SST) based on both NOAA/AVHRR (1981.07-2002.12) and MODIS/AQUA (2003.01-2009.12) ocean color data was analyzed. In addition, five climate indices, Arctic Oscillation Index (AO), Siberian High Index (SH), Aleutian Low Pressure Index (ALP), East Asia Winter Monsoon Index (EAWM) and Pacific Decadal Oscillation (PDO) which are the main indicators of climate changes in the northwestern Pacific were used to study the relationship between the magnitude of the estimated spawning ground and climate indices. The area of the estimated spawning ground was highly correlated with the total catch of common squid throughout four decades. The area of the estimated spawning ground was negatively correlated with SH and EAWM. Especially, PDO was negatively correlated with the area of the spawning ground in the northwestern Pacific (r = -0.39) and in the southern part of the East Sea (r = -0.38). There was a positive relationship between the AO and the area of the spawning ground in the northwestern Pacific (r = 0.46) as well as in the southern part of the East Sea (r = 0.32). Temporally, the area of the winter spawning ground in the southern part of the East Sea in the 1980s was smaller than those areas in the 1990s and 2000s, because the area was disconnected with the western coastal spawning ground of Japan in the 1980s, while the area had been made wider and more continuous from the Korea strait to the western coastal water of Honshu in the 1990s and 2000s.