Precession and atmospheric CO₂ modulated variability of sea ice in the central Okhotsk Sea since 130,000 years ago

Lo, Li,Belt, Simon T.,Lattaud, Julie,Friedrich, Tobias,Zeeden, Christian,Schouten, Stefan,Smik, Lukas,Timmermann, Axel,Cabedo-Sanz, Patricia,Huang, Jyh-Jaan,Zhou, Liping,Ou, Tsong-Hua,Chang, Yuan-Pin Elsevier 2018 Earth and planetary science letters Vol.488 No.-

<P><B>Abstract</B></P> <P>Recent reduction in high-latitude sea ice extent demonstrates that sea ice is highly sensitive to external and internal radiative forcings. In order to better understand sea ice system responses to external orbital forcing and internal oscillations on orbital timescales, here we reconstruct changes in sea ice extent and summer sea surface temperature (SSST) over the past 130,000 yrs in the central Okhotsk Sea. We applied novel organic geochemical proxies of sea ice (IP<SUB>25</SUB>), SSST ( TEX L 86 ) and open water marine productivity (a tri-unsaturated highly branched isoprenoid and biogenic opal) to marine sediment core MD01-2414 (53°11.77′N, 149°34.80′E, water depth 1123 m). To complement the proxy data, we also carried out transient Earth system model simulations and sensitivity tests to identify contributions of different climatic forcing factors. Our results show that the central Okhotsk Sea was ice-free during Marine Isotope Stage (MIS) 5e and the early-mid Holocene, but experienced variable sea ice cover during MIS 2–4, consistent with intervals of relatively high and low SSST, respectively. Our data also show that the sea ice extent was governed by precession-dominated insolation changes during intervals of atmospheric CO<SUB>2</SUB> concentrations ranging from 190 to 260 ppm. However, the proxy record and the model simulation data show that the central Okhotsk Sea was near ice-free regardless of insolation forcing throughout the penultimate interglacial, and during the Holocene, when atmospheric CO<SUB>2</SUB> was above ∼260 ppm. Past sea ice conditions in the central Okhotsk Sea were therefore strongly modulated by both orbital-driven insolation and CO<SUB>2</SUB>-induced radiative forcing during the past glacial/interglacial cycle.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The first orbital timescale proxy-model sea ice-sea surface temperature records from the northwestern subarctic Pacific Ocean. </LI> <LI> Strong precession forcing controlled and sea ice variations are modulated by greenhouse gas radiative forcing. </LI> <LI> Sea ice remained free in the central Okhotsk Sea during MIS 5e due to high greenhouse gas radiative forcing. </LI> </UL> </P>

Characteristics of Weather and Climate over the Okhotsk Sea

KIM Young Seup,HAN Young Ho,CHEONG Hyeong Bin,DASHKO Nina A.,PESTEREVA Nina M.,VARLAMOV Sergey M. The Korean Society of Fisheries and Aquatic Scienc 1997 한국수산과학회지 Vol.30 No.6

The Okhotsk Sea is unique natural object with climatic peculiarities. The climate of the Okhotsk Sea results from the general distribution of solar radiation during a year, and the characteristics of the atmospheric circulation that varies through a year: In cold half year the main pressure formations are Siberian high and Aleutian low. Asian low centered on Afghanistan dominates over the Asian continent in summer. The North-Pacific sea surface is under effect of permanent North Pacific high. The changes in their position from year to year are very significant. The anticyclonic activity over the Far Eastern Seas is one of the main factors for the formation of weather anomalies over the adjacent territories. The analysis of summer weather characteristics over the coast of Okhotsk and East Sea using the data obtained from Hydrometeorological stations during $1949\~1990$ showed that, to a great extent, distribution of the air temperature depends on thermal state of the Okhotsk Sea and atmospheric circulation over it. We show some relations between weather characteristics and the intensity of atmospheric action center for the North Pacific high in summer when its ridge propagates to Okhotsk Sea. Correlation coefficients between air pressure over the Okhotsk Sea and air temperature for the coastal areas reach up to 0.7. Analysis of the spatial-temporal distribution of main meteorological values over the Okhotsk Sea such as air pressure, and air temperature are also performed.

북극권의 진출로 오호츠크 해와 베링 해 지역연구: 선적활동과 장애요인

한종만 배재대학교 한국-시베리아센터 2018 한국시베리아연구 Vol.22 No.1

Global warming in the Arctic region is twice as fast as that in other regions. Arctic sea ice in summer keeps renewing its lowest extent every year since 2010, which has been monitored by satellite observations since 1970s. This decrease of Arctic sea ice is expected to benefit the usage of the Arctic route, and developments and utilizations of energy, fishery, and ecotourism resources in the Arctic Circle. The vessels in the Russian Far East and the vessels of Korea, China, and Japan using Arctic shipping route, which includes the Northeast Passage, the Northwest Passage, and the Transpolar Sea Route, trail the Bering Strait, through the East Sea, the Sea of Okhotsk, and the Bering Sea. Therefore, developments in the Arctic region and shipping activities across the Bering Strait are expected to increase steadily. Although the developments and increased shipping activities can raise risks of accidents and harm the ecosystem, not only infrastructure for prevention and post-management of accidents is lacking, but also national, bilateral, and multilateral governance system for environmental protection has not been settled. Sustainable ecosystems should be taken into account in the developments, uses of the Arctic route, and the governance. In this article, Chapter 2 outlines the physical and human geographical characteristics of the Sea of Okhotsk and the Bering Sea. Chapter 3, the current status and analysis of marine activity in the study area, contemplates the trade structure and current status of importation and exportation, ports, and shipment through the Aleutian Islands and the Bering Strait. Chapter 4 explores the obstacles to the Arctic route and activation strategies for the route. 북극 지역의 온난화는 기타 지역보다 2배나 빠르게 상승하고 있으며, 1970년대 인공위성 관측을 시작한 이래 2010년부터 여름철 북극해 얼음 규모는 매번 최소치를 갱신하고 있다. 북극해의 해빙으로 북극항로의 이용과 북극권의 자원/에너지 개발, 수산자원의 활동, 생태관광자원의 이용가능성을 높여주고 있다. 러시아 극동지역과 한중일의 선박은 동해 , 오호츠크 해, 베링 해를 거쳐 베링해협을 통과해야만 가능한 북극항로는 북동항로, 북서항로, 북 극점 경유 항로로 구분된다. 북극개발과 베링해협 통과 선적활동은 꾸 준히 증가할 것으로 예상된다. 북극권 개발과 선적활동과 증가로 야기되는 여러 형태의 사고 위험 성과 부정적 생태계의 변화 가능성도 병행되고 있으며, 사전 및 사후 사고 예방을 위한 인프라 시설의 부족과 부재뿐만 아니라 환경보호를 위한 국가별, 쌍무간, 다자간 거버넌스 시스템도 정착되지 않은 상황이 다. 개발과 항로 이용과 거버넌스는 지속가능한 생태계에 기반을 둔 차 원에서 이루어져야만 한다. 이러한 맥락에서 본 논문 제2장은 오호츠크 해, 베링해협과 베링 해 남부와 북부 지역의 자연 및 인문 지리적 특성을 개관한 후 제3장 연 구공간 해양활동의 현황과 분석에서는 수출입 현황과 구조, 항구 현황, 알류샨열도와 베링해협 통과 선적 현황을 고찰한다. 제4장에서는 북극 항로의 장애요인과 활성화 방안을 모색한다.

Reconstruction of surface water conditions in the central region of the Okhotsk Sea during the last 180kyrs

Khim, Boo-Keun,Sakamoto, Tatsuhiko,Harada, Naomi Elsevier 2012 Deep-sea research. Part II, Topical studies in oce Vol.61 No.-

<P><B>Abstract</B></P><P>Core GC9A, a 6.7m long gravity core collected from the central region of the Okhotsk Sea during Cruise YK0712 on R/V Yokosuka (JAMSTEC), was used to reconstruct the changes in surface water conditions by measuring biogenic components (biogenic opal, CaCO<SUB>3</SUB>, total organic carbon and <I>δ</I><SUP>15</SUP>N of sediment organic matter) of sediment samples. The age of Core GC9A was determined indirectly by graphic correlation comparing the b<SUP>⁎</SUP> (psychometric yellow–blue chromaticness) values with those of well-dated Core MD01-2415, with complement to the tephra layer (K3; 50ka). The bottom age of Core GC9A was estimated to be about 180kyr; therefore it provides the history of surface water conditions from MIS 1 to MIS 6. The biogenic opal, CaCO<SUB>3</SUB>, and TOC contents were high during the interglacial periods as expected, indicating enhanced surface water production under warm climatic conditions. This condition resulted from sufficient nutrient supply to the surface waters by active vertical mixing, which was validated by low δ<SUP>15</SUP>N values of the sediment organic matter. In contrast, surface water productivity was depressed during the colder glacial periods, probably due to the expanded sea-ice distribution and limited nutrient supply. However, the glacial sediments had moderately high δ<SUP>15</SUP>N values, indicating enhanced nitrate utilization resulting from the limited nutrient supply caused by strong stratification of the surface water. High δ<SUP>15</SUP>N values were also observed during the deglaciation, which was attributed to the increased nitrate utilization during enhanced surface water productivity. However, the low δ<SUP>15</SUP>N values during the glacial and deglacial periods may be attributed to the increased supply of terrestrial organic matter. Diatom production was primarily responsible for surface water paleoproductivity during the interglacial periods rather than coccolithophores. However, the succession of glacial to early deglacial coccolithophore production and late deglacial to interglacial diatom production was remarkable, corresponding to the present-day seasonal phytoplankton succession. Such an advanced coccolithophore production relative to diatom production might be attributed to the degree of nutrient availability associated with surface water conditions on the basis of variations in the δ<SUP>15</SUP>N value. Finally, the opal and TOC contents decreased abruptly in conjunction with a gradual decrease in CaCO<SUB>3</SUB> content from about 2ka, which seems to implicate a late Holocene sudden decrease in paleoproductivity in the central region of the Okhotsk Sea. According to the increase in δ<SUP>15</SUP>N values during this interval, nutrient availability appears to be poor, which is likely attributed to the resumed strong stratification that occurred due to the southward shift of the Aleutian Low atmospheric pressure system.</P>

Natural gas hydrate occurrence and detection in the Sea of Okhotsk

진영근(Jin, Young-Keun),CHAOS Scientific Party, CHAOS 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.11

The Sea of Okhotsk is the unique area providing the highest methane production rate of the northern hemisphere. The area of focused fluid venting offshore the NE Sakhalin continental slope was investigated during the CHAOS (Hydro-Carbon Hydrate Accumulations in the Okhotsk Sea) expeditions onboard of RV Akademik Lavrentyev In 2003, 2005 and 2006. The International Research Project CHAOS (Russia-Korea-Japan) aimed at the study of gas hydrate formation processes associated with the fluid venting in the Sea of Okhotsk. Several new gas hydrate accumulations were discovered during the cruise. Hydrate-associated structures have been named as KOPRI, VNIIOKeangeologia, POI and KIT (the names of cruise participant institutes) Some of hydrate-bearing cores contain big amount of gas hydrates: massive gas hydrate layers (up to 35cm thick) were recovered. The shallowest submarine gas hydrate accumulations in the world (at the depth less then 400m) were discovered during the cruise.

북극권 진출을 위한 해양공간 인문지리: 동해-오호츠크 해-베링 해

김정훈,한종만 배재대학교 한국-시베리아센터 2019 한국시베리아연구 Vol.23 No.2

As the accessibility of the Arctic Circle is increasing, researches on the Arctic Circle are very actively being carried out at home and abroad. However, these studies are mostly conducted in the individual areas of political, economic and scientific domains, so it is necessary to analyze values at a comprehensive level as a space where geopolitical, geographical and geocultural problems work in combination. To realize this end, the following three things need to be considered. First, the research area is a place where the interests in resource development and northern route management that will determine the future of the Korean peninsula in the 21st century as well as the Artic neighbors are concentrated. Second, the linkage of the research area requires systematic research, that is, each research topic is closely linked by the future development strategy (blueprint) of the relevant countries. Third, all research topics are integrated studies that are investigated in combination by closely linked geopolitical, geopolitical and geocultural approaches. In particular, since the study of the Ohotsk Sea and the Coast of Bering Sea, which are the gateways to the Arctic, is a necessary space for approaching the Arctic, the future growth engine of the Republic of Korea, it is necessary to prepare for the growth in advance. Therefore, the study aims to explore the comprehensive value and analysis contents & methods of the Artic from the views of humanities and geographical approach to the research space. 본 연구공간(동해-오호츠크해-베링해)은 한국사회에 에너지·자원 확보/수입원/공급처의 다변화, 물류유통, 해양세력과 대륙세력으로의 확장, 생활공간의 확대, 해외 식량 기지의 확보(수산업 등), 환경과 생태에 대한 글로벌 이슈의 충족, 녹색성장의 토대, 남북한 통합 촉진과 북한경제 발전의 연착륙유도 등을 제공할 수 있는 미래 한국사회의 ‘기회의 공간’으로 작용할 수 있다. 이에 따라 본 연구를 통해 국제사회와 우리의 기대에 부합하는 미래의 한국사회를 건설하기 위한 선도적 준비로써 해당지역의 지정, 지경 지문화적 의미와 연구필요성 등을 제기해보고자 한다. 북극권의 접근성이 높아가고 있는 상황에서 북극권에 대한 연구는 국내외적으로 매우 활발하게 진행되고 있는 상황이다. 그러나 이들 연구는 대부분 정치적, 경제 및 과학적 입장의 개별적 영역에서 진행되고 있어 지정, 지경 및 지문화적 문제들이 복합적으로 작용하는 공간으로서 종합적 차원에서의 가치와 분석 등이 필요하다고 생각한다. 이를 실현하기 위해서는 다음과 같은 세 가지 사항이 먼저 고려될 필요성이 있다. 첫째, 연구공간은 21세기 한반도뿐 아니라 해당국들의 미래를 결정할 자원개발과 북방항로 운용의 이해관계가 집중된 곳; 둘째, 연구대상지역의 연계는 시스템적 연구(Systemic Approaches)를 요구, 즉 각 연구 주제는 관련국의 미래 발전 전략(청사진)에 의해 상호 긴밀하게 연계; 셋째, 모든 연구 주제는 긴밀하게 연계된 지정학적, 지경학적, 지문화적 접근법들에 의해 복합적으로 연구되는 통합연구(Integrated Studies). 특히, 우리의 입장에서 북극을 향하는 관문인 오호츠크 해 및 베링 해 연안 지역연구는 향후 대한민국의 미래성장 동력 지역인 북극에 접근하는데 있어 반드시 필요한 공간으로 이에 대한 선도적인 준비가 필요하다고 판단되기에 본 연구를 통해, 연구공간에 대한 인문·지리학적 접근에서 지역의 종합적 가치와 분석 내용과 방법 등을 모색하고자 한다.

Brown algae (Phaeophyceae) from Russian Far Eastern seas: re-evaluation of Laminaria multiplicata Petrov et Suchovejeva

Klochkova, Tatyana A.,Kim, Gwang-Hoon,Lee, Kyung-Min,Choi, Han-Gu,Belij, Mihail N.,Klochkova, Nina G. The Korean Society of Phycology 2010 ALGAE Vol.25 No.2

Eight unusual individuals of a laminariaceaen species were collected from the Sea of Okhotsk in 1974 and described as a new species, Laminaria multiplicata Petrov et Suchovejeva in 1976. Since that time no new information, including pictures and numerical data, has been provided, although the species was cited in floristic lists of the Sea of Okhotsk based on the first record in 1976. We investigated a type and 3 paratypes of L. multiplicata and strongly believe that they were wrongfully identified abnormal plants of L. gurjanovae A. Zinova. Therefore, the species L. multiplicata needs to be closed.

Brown algae (Phaeophyceae) from Russian Far Eastern seas: re-evaluation of Laminaria multiplicata Petrov et Suchovejeva

Tatyana A. Klochkova,김광훈,Kyung Min Lee,Han-Gu Choi,Mihail N. Belij,Nina G. Klochkova 한국조류학회I 2010 ALGAE Vol.25 No.2

Eight unusual individuals of a laminariaceaen species were collected from the Sea of Okhotsk in 1974 and described as a new species, Laminaria multiplicata Petrov et Suchovejeva in 1976. Since that time no new information, including pictures and numerical data, has been provided, although the species was cited in floristic lists of the Sea of Okhotsk based on the first record in 1976. We investigated a type and 3 paratypes of L. multiplicata and strongly believe that they were wrongfully identified abnormal plants of L. gurjanovae A. Zinova. Therefore, the species L. multiplicata needs to be closed.

Volume Transport through the La-Perouse (Soya) Strait between the East Sea (Sea of Japan) and the Sea of Okhotsk

Saveliev Aleksandr Vladimirovich,Danchenkov Mikhail Alekseevich,Hong Gi-Hoon Korea Institute of Ocean ScienceTechnology 2002 Ocean and Polar Research Vol.24 No.2

Seasonal and interannual variation of volume transport through the La-Perouse Strait were estimated using the difference of sea level observed at Krillion of Sakhalin, Russia, and Wakkanai of Hokkaido, Japan, during the period of 1975-1988. Historical sea level measurements between Russian and Japanese tide gauge data were normalized using an independent direct volume transport measurement. Volume transport from the East Sea (Sea of Japan) to the Sea of Okhotsk varied from -0.01 to 1.18 Sv with an annual mean value of 0.61 Sv. Monthly water transport rates showed a unimodal distribution with its maximum occurring in summer (August) and minimum in winter (December-February). The annual mean volume transport varied from 0.2 to 0.8 Sv during the period of 1975-1988 with the maximum variance of 0.6 Sv.

Influence of Okhotsk Sea Blocking on Summer Precipitation Over South Korea

Chan-Yeong Song,Young-Hyun Kim,Eung-Sup Kim,Joong-Bae Ahn 한국기상학회 2021 한국기상학회 학술대회 논문집 Vol.2021 No.10

This study examined the influence of atmospheric blocking on the variability of precipitation over South Korea during summer (June-July-August) by defining the blocking frequency over the Okhotsk Sea (Okhotsk Sea blocking frequency; OK_BF). Partial correlation analysis was conducted to separate the contribution of OK_BF to the precipitation variation from that of the low-level meridional wind (LLMW) because LLMW over the region is another important aspect of summer precipitation in South Korea. The barotropic structures of positive geopotential height anomalies over the Okhotsk Sea associated with increasing OK_BF can induce negative temperature anomalies over South Korea due mainly to the equatorward advection of cold air masses from higher latitudes. The enhanced meridional temperature gradient can cause increases in baroclinic instability and zonal wind vertical shear according to the thermal wind balance. This instability can induce anomalous cyclonic circulations over South Korea, resulting in positive precipitation anomalies. The partial correlation coefficients (R<SUP>2</SUP>=0.35 0.40) between the OK_BF and precipitation indices, including mean precipitation, extreme precipitation intensity, wet days, and consecutive wet days, were all statistically significant at the 95% confidence level. Overall, the effects of the increasing OK_BF on both precipitation and potential evapotranspiration can intensify the surface water budget in South Korea.