https://repository.kopri.re.kr/handle/201206/5378 2026-04-14T11:55:59Z https://repository.kopri.re.kr/handle/201206/6713 Title: Bacterial Communities of Surface Mixed Layer in the Pacific Sector of the Western Arctic Ocean during Sea-Ice Melting Authors: Lee, Yoo Kyung; Han, Dukki; Kang, Ilnam; Ha, Ho Kyung; Kim, Hyun-cheol; Kim, Ok-Sun; Lee, Bang Yong; Cho, Jang-Cheon; Hur, Hor-Gil Abstract: From July to August 2010, the IBRV ARAON journeyed to the Pacific sector of the Arctic Ocean to monitor bacterial variation in Arctic summer surface-waters, and temperature, salinity, fluorescence, and nutrient concentrations were determined during the ice-melting season. Among the measured physicochemical parameters, we observed a strong negative correlation between temperature and salinity, and consequently hypothesized that the melting ice decreased water salinity. The bacterial community compositions of 15 samples, includicng seawater, sea-ice, and melting pond water, were determined using a pyrosequencing approach and were categorized into three habitats: (1) surface seawater, (2) ice core, and (3) melting pond. Analysis of these samples indicated the presence of local bacterial communities;a deduction that was further corroborated by the discovery of seawater- and ice-specific bacterial phylotypes. In all samples, the Alphaproteobacteria, Flavobacteria, and Gammaproteobacteria taxa composed the majority of the bacterial communities. Among these, Alphaproteobacteria was the most abundant and present in all samples, and its variation differed among the habitats studied. Linear regression analysis suggested that changes in salinity could affect the relative proportion of Alphaproteobacteria in the surface water. In addition, the species-sorting model was applied to evaluate the population dynamics and environmental heterogeneity in the bacterial communities of surface mixed layer in the Arctic Ocean during sea-ice melting. 2014-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/8358 Title: Differential sea ice bottom melt rate during late summer in the Chukchi Authors: J. Wilkinson; K. Jackson; B. Hwang; Ha, Ho Kyung; Chung, Kyung Ho; Kim, Tae-Wan Abstract: In 2011 summer four sea ice mass balance buoys were deployed in the Chukchi Borderland region. Even though the buoys drifted together within less than 100 km range, measurements from the buoys exhibit quite a different bottom ice melt rates, ranging from less than 1 cm per day up to 5 cm per day. This was equivalent to less than half meter or up to 0.76 m of total bottom ice melt during about a month in August. The intensive melt rate was associated with warmer water temperature (about -0.9 to 0.5C). Our results also showed cumulative solar heat input between intensive and moderate melting was different by 50-80 MJ^m-2, confirming significant role of solar heating for the differential bottom melt rates. The effects of longwave and turbulent fluxes and sea ice drift divergence on sea ice melt are also discussed. 2012-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/8357 Title: Retrieval of the floe size and melt pond statistics of Arctic sea ice using high-solution SAR Authors: B. Hwang; S.H. Lee; Chung, Kyung Ho; W.M. Moon; H.S. Jung; D.J. Kim Abstract: In this paper we present the recent works on retrieving sea ice floe size distribution and melt pond statistics (pond size and shape) by using high-resolution SAR. The results contains the image analysis from TerraSAR-X data as well as airborne-SAR system deployed on a helicopter in the Chukchi Sea of the Arctic Ocean. Our study highlights promising results in retrieving these important but difficult parameters, as well as discussing limitations we have for the retrievals airborne-SAR system deployed on a helicopter in the Chukchi Sea of the Arctic Ocean. Our study highlights promising results in retrieving these important but difficult parameters, as well as discussing limitations we have for the retrieval 2012-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/8468 Title: 오호츠크해 사할린 북동사면의 가스하이드레이트와 가스분출구 분포와 특성 Authors: Jin, Young Keun; H. Shoji; B. Boris; A. Obzhirov Abstract: 오호츠크해 사할린섬 북동대륙사면에는 가스하이드레이트와 가스분출구 (gas seep)가 잘 발달되 어 있다. 2003년부터 2010년까지 이 지역의 가스하이드레이트 분포와 가스분출현상을 연구하는 한국-러시아-일본 국제공동연구탐사 (CHAOS, SSGH)가 수행되었다. 이 국제공동연구탐사를 통해 서 2500 L-km의 고해상도 탄성파자료, 2300 km2의 side-scan sonar 영상과 88개 정점의 천부퇴 적물를 획득하였다. 총 17개 정점에서 가스하이드레이트 시료를 채취하였고, 약 900개의 가스분 출기둥 (gas flare)과 840여개의 해저면 가스분출구조 (gas seepage structure)를 발견하였다. 특징적으로 35 cm 두께의 순수한 가스하이드레이트 시료와 385 m의 얕은 수심의 해저면에서 가 스하이드레이트 시료를 채취하였다. 연구지역은 차가운 해수온도로 인해 가스하이드레이트 안정 대의 상부 경계가 약 300 m 수심에 위치한다. 이 지역에서의 활성가스분출현상은 지구물리 자료 에서 다양한 형태로 확인이 된다. 해수층에서는 높은 수중음향이상체인 가스분출기둥, 해저면에 서는 높은 후방반사강도를 보이는 포크마크 (pockmark)와 언덕구조 (mound), 퇴적층에서는 해저 면 모방반사층 (bottom simulating reflector)과 가스기둥구조 (gas chimney)를 수반한다. 또 한 해저면에서 높은 메탄농도를 보이며, 천부가스하이드레이트가 발달해 있다. 이런 구조들은 서로 연관되어 함께 나타나는데, 지층심부에서 메탄가스가 가스기둥을 따라 해저면까지 이동하 고 해저면에 가스분출구조를 형성하며, 천부가스하이드레이트를 형성하고 남은 메탄가스가 해수 층으로 분출하는 현상이 각각의 탐사자료로 확인된 것이다. 연구지역의 가스분출구조 2011-01-01T00:00:00Z