• 대한조선학회논문집
• /
• 제49권2호
• /
• pp.189-195
• /
• 2012

The ice trials of the first Korean icebreaking research vessel "ARAON" were performed at the Arctic Ocean in July-August 2010. The sea ice concentrations of Arctic Ocean were 4/10 to 10/10 and the range of sea ice thickness was roughly 1.0 to 3.5m. In this research, sea ice thickness characteristics at the old ice floes were determined from results of drill hole and apparent conductivity measurements. Especially we measured apparent conductivity using an electromagnetic induction instrument (EM31-MK2) and estimated the sea ice thickness through the empirical equation from Cold Regions Research & Engineering Laboratory, CRREL. The results of estimated sea ice thickness were compared to drill hole measurement results and then, we suggest the new empirical equation to estimate sea ice thickness of single layer type sea ice during the summer season of Arctic Ocean by curve fitting approach to these data.

• 한국기계기술학회지
• /
• 제13권1호
• /
• pp.23-29
• /
• 2011

The measurement of ice properties such as thickness, strength are important to know the performance of the ice breaking vessel. The measuring equipment of ice properties and methods are summarized in this paper. The actual measured data are also described. The strength of ice at Svalbard area on April 2010 is much stronger than the Chukchi Sea on August 2010. The mean strength of Svalbard is about 500 kPa and one of Chukchi Sea is 250 kPa. The first sea trial in Arctic sea using Araon was carried out in the Chukchi Sea. The power and speed was also measured to check the ship performance in ice. The speed was measured from GPS(Global Positioning System) and engine power was recorded from DPS(Dynamic Positioning system) of Araon. The design target of Araon in level ice is 3 knots in 1m thickness and 630 kPa flexible strength but mean speed in Chuckchi sea is 3.98 knots when 6.6 MW engine power, 2.4m ice thickness and 250 kPa strength. This results comes from the difference of ice types and the weak flexible strength of ice but it will be a good information to know the performance of Araon in similar ice condition.

• 대한조선학회논문집
• /
• 제48권5호
• /
• pp.421-425
• /
• 2011

To know the speed performance of "ARAON" in Arctic ice field, the measurement of ice properties which is ice thickness & strength, snow depth and free board were performed on July 2010. The measuring method of nautical signals such as heading angle, power of engine, wind & current information etc. was described in this paper. The speed sea trials in ice were performed on the four different positions with different ice properties and engine powers because the uniform level ice is not detected in the Chukchi Sea. The test field was partially constrained ice floe with hummocks and it was superposed with small broken ice pieces each other. All of the measured ice properties were compared and evaluated according to the results of sea trial. The relations between speed, ice thickness, strength and power were summarized. Consequently according to the sea trial results, the speed of ARAON is 2.78knots at the 2.49m ice thickness with 6.55MW engine power.

• 대한원격탐사학회지
• /
• 제34권6_2호
• /
• pp.1229-1238
• /
• 2018

본 연구에서는 위성영상 기반의 북극의 해빙 농도 시계열 데이터를 이용하여 베링해의 해빙 상태가 척치해 해빙 농도 변화의 전조로서 작용할 수 있는지를 실험하였다. 해빙 농도 자료는 1982년부터 2017년의 36년간의 월평균 시계열 데이터로 이뤄져 있으며, 베링해의 해빙 농도와 척치해 해빙 농도 사이의 관계성을 전송 엔트로피 측정을 통해 분석하였다. 전송 엔트로피는 두 개의 확률변수 또는 신호 간의 비선형적 연관성을 파악하게 해주는 동시에 변수 사이의 시간 간격 조절을 통해 인과관계를 추정할 수 있는 측정이다. 해빙 농도를 대상으로 한 측정 결과, 베링해의 과거 3, 5, 6개월 전의 해빙 농도값이 척치해 해빙의 변화에 관련되어 있음을 알 수 있었다. 특히, 베링해의 해빙 농도값이 극소를 나타냈을 때, 5개월 후의 척치해의 해빙 농도는 감소될 확률이 약 70%로 나타났다. 이는 태평양에서 베링해협을 통해 북극해로 유입되는 해류가 베링해의 해빙 농도를 감소시킨 후 해협을 통해 척치해로 이동하여 해빙을 녹이는 과정에 비롯한 것으로 사료된다. 향후 위성데이터에 정보 이론으로 접근하는 이 연구를 더 발전시켜 어떤 시점과 시간적 스케일로 특이 패턴이 발생하는지 조사하고 그 기간에 관련된 해양-대기의 패턴 또는 사건들을 분석하여, 떨어진 두 지역의 해빙 농도 상태에 내재된 연관성에 대한 심층적 이해가 가능할 것이다.

• 한국해양공학회지
• /
• 제28권5호
• /
• pp.423-428
• /
• 2014

Ice loads may be conveniently categorized as local ice loads and global ice loads. Local ice loads are often defined as ice pressures acting on local areas of shell plates and stiffeners. Therefore, local ice loads are defined in all ice class rules. However, directly measuring the local ice pressure using the actual ice class vessel is a very difficult task because appropriate instruments for direct measurement must be installed on the outer hull, and they are easily damaged by direct ice contacts/impacts. This paper focuses on the estimation of the local ice pressure using the data obtained from icebreaking tests in the Arctic sea in 2010 using the Korean icebreaking research vessel (IBRV) ARAON. When she contacted the sea ice, the local deformation of the side shell was measured by the strain gauges attached to the inside of the shell. Simultaneously, the contact area between the side shell and sea ice is investigated by analyzing the distribution of the measured strain data. Finally, the ice pressures for different contact areas are estimated by performing a structural analysis.

• 대한조선학회논문집
• /
• 제49권1호
• /
• pp.45-51
• /
• 2012

Sea ice properties have been considered a key indicator in the structural design criteria of icebreaking vessels and arctic offshore platforms to estimate design ice load and resistance for their safety management in Arctic Ocean. A measurement study of sea ice properties was conducted during July to August of 2011 with the Korean icebreaking research vessel "Araon" around Chukchi Borderland. The sea ice concentration appears to be rapidly decreasing during this cruise. Ice condition seems to be thick second-year ice and multi-year ice and then, a lot of melt ponds were observed in the surface of ice floe. Calculated flexural strength of sea ice was about 250~550kPa, ice thickness was roughly 1.3~3.0m. In this research we performed field experiment to measure ice temperature along the depth, thickness, density, salinity, brine volume ratio and crystal structure. Apparent conductivities derived with the electromagnetic induction instrument were compared to drill hole measurement results and accuracy of sea ice thickness estimation formula was discussed.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
• /
• pp.1019-1022
• /
• 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.

• Ocean and Polar Research
• /
• 제45권3호
• /
• pp.155-172
• /
• 2023

The collapse of ice shelves is a process that can severely increase the rise of global sea-levels through the reduction of the buttressing effect of ice shelves and the consequent acceleration of the ice flow of ice sheets. In recent years, the West Antarctic ice shelves in the Amundsen Sea, whose buttressing effect is essential for a great part of the West Antarctic ice sheet, have been experiencing the most rapid melting and thinning in the world. The melting of the West Antarctic ice shelves is caused primarily by heat transported by Circumpolar Deep Water (CDW). For this reason, it is important to investigate ice-ocean interactions that could influence the melting of ice shelves and evaluate the stability of West Antarctic ice shelves. A lot of researchers have been actively investigating the West Antarctic ice shelves in the Amundsen Sea. High-impact journals have recognized the importance of and published studies on ice-ocean interactions occurring near and under the ice shelves as well as the connections among ice shelves. However, in situ observations are limited due to extreme weather and sea-ice conditions near the ice shelves; therefore, many scientific questions remain unanswered. This study introduces the characteristics of the Amundsen Sea and investigate the past and latest research issues in this region. This study also gives suggestions regarding important scientific questions and directions for future research that should help early-career scientists take the lead in future research on the melting dynamics of the West Antarctic ice shelves in the Amundsen Sea.

• 대한원격탐사학회지
• /
• 제27권5호
• /
• pp.535-542
• /
• 2011

본 연구에서는 서남극 Canisteo 반도와 그 주변 지역이 촬영된 2쌍의 ERS-1/2 tandem pair에 4-pass DInSAR 기법을 적용하여 표면 변위도를 생성하였고, 빙하와 해빙의 표면 변위를 해석하였다. 표면 변위도에서 빙하는 매우 빠른 움직임을 나타냈으며 인접해 있는 정착빙을 밀어내어 정착빙 표면에서는 빙하와 같은 방향의 변위가 관찰되었다. Cosgrove 빙붕도 큰 변위를 나타냈으며, 인접해 있는 정착빙을 밀어내는 것이 관찰되었다. 일부 해빙은 정착빙과 반대 방향의 움직임을 보였다. 이는 해빙이 해류에 영향을 받는 유빙이기 때문이며, 이로부터 정착빙과 유빙의 경계를 확인할 수 있었다. 빙붕과 빙상의 표면은 SAR영상에서 유사한 밝기를 보이며, 간섭도에서도 비슷한 정도의 간섭띠 변화율을 나타내 두 빙체를 쉽게 구분 할 수 없었다. 그러나 움직임이 큰 빙붕과 변위가 거의 없이 안정적인 빙상의 경계를 절대위상복원 후 생성한 변위도를 통해서 쉽게 확인할 수 있었다.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
• /
• pp.1015-1018
• /
• 2006

The use of passive microwave data for estimating sea-ice thickness is limited by strong dependence of emissivity on near-surface brine. However, this particular characteristic becomes a basis for an algorithm to estimate thickness of thin sea-ice if a thickness-salinity-emissivity relationship is established. This study aims at developing an algorithm to estimate sea ice thickness on the basis of this relationship. In order to establish a thickness-salinity-emissivity relationship, we have conducted multi-platform synchronous observations in the Sea of Okhotsk. We note a positive relationship between thickness and brightness temperature. From observations, we also establish an empirical relationship between salinity and emissivity, thus between thickness and brightness temperature. The derived relationship is qualitatively similar to the one based on Hoekstra and Cappillino's formulation. Our results suggest that for thin sea-ice in the winter period there is potential to develop an algorithm to estimate sea-ice thickness.