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1.
Offshore development and growing prospects of commercial shipping in the Arctic pose the challenge of optimal ship routing in ice. Route selection in spatially distributed ice conditions significantly affects the voyage time and determines the efficiency of shipping. Most of the applied methods of ice routing solve the problem of a single vessel route selection without considering icebreaker support. At the same time, the real practice of ice navigation is closely connected with icebreaker assistance. It allows reducing the voyage time and fuel consumption, while having additional costs for icebreaker services. Such opposite trends set an optimization task that has not been studied in detail before. In this article, we presented the formulation of a Single Vessel and Icebreaker Assisted Ice Routing optimization problem in non-stationary ice conditions. We considered the icebreaker assistance as an integral part of the overall route optimization problem, and used the economic criterion to optimize both ship route and amount of icebreaker involvement. The article contains the adapted mathematical formulations of classical graph-based and wave-based routing problems in order to consider icebreaker assistance. To prove the practical applicability of these formulations, we developed special subject-oriented research software and implemented there both graph-based (Dijkstra, A*) and the wave-based ice routing methods. Using this developments, we conducted several case studies and made the analysis of strengthens and weaknesses of the alternative routing methods in case of ice operation. The results of the study may serve an additional step to the practical implementation of ice routing technologies and planning of icebreaker resources. 相似文献
2.
吊舱推进装置在极地船舶中被广泛应用，其转舵模块可以带动螺旋桨摆动从而产生任意方向的推进力，使船舶操纵更为灵活。提出了一种吊舱推进船舶冰区操纵的离散元方法，对具有吊舱推进装置的冰区船舶破冰过程进行了数值模拟。以“雪龙2”号破冰船为研究对象，计算分析了船舶定速直航时的冰阻力，并通过与Lindqvist经验公式的对比验证了冰阻力计算的合理性。在此基础上进一步对船舶在不同冰厚、不同吊舱转向角下的回转破冰运动进行了离散元模拟，分析了回转半径与船长比值随冰厚的变化规律。计算结果表明：船舶的回转性能随冰厚的增大而降低，并随吊舱转向角的增大而显著提高。 相似文献
3.
西北航道是指从北大西洋经加拿大北极群岛进入北冰洋,再进入太平洋的航道,是连接大西洋和太平洋的捷径。为了探讨西北航道通航期极端天气条件下强风及海冰对波浪场的影响机制,建立并验证了考虑海冰影响下的西北航道风浪演化模型,并以2012年8月北极气旋登陆期间为例探讨西北航道通航期波浪特性及波能流密度的时空演化及其对风和海冰的响应。研究结果表明,北极夏季海冰大多分布于西北航道以北海域,而风向大部分集中在SSW(南偏西22.5°)至SW(南偏西45°),西北航道海冰的存在并不会引起有效风区的明显减少,也不会引起无冰海域波能流的明显减小(不超过5%)。但是,当风向变为北向风时,无冰海域波能流减小幅度最多高达62%。最后,综合海冰和波浪要素的时空分布,提出了极端天气条件下西北航道通航期的最佳适航路线,为西北航道的夏季安全通航提供了科学依据。 相似文献
4.
P. Bourgain J.C. Gascard 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(7):745-756
As a key structure to understand the role of the ocean on the sea ice mass balance, the Arctic Ocean halocline and its spatiotemporal variability require serious attention. In this paper, we are proposing a new definition of the halocline, which is based on the salinity gradient structure, taking into account both the salinity amplitude and the thickness of the halocline. The Brunt Vaisala frequency is used as the halocline stratification index. CTD data collected from 1997 to 2008 and coming from various sources (icebreaker cruises, drifting buoys, etc.) are used to determine the halocline, and its time and space variability during three time periods, with a special focus on three main regions of the Arctic Ocean: the Canada basin, the Makarov basin and the Amundsen basin. Observations reveal that the halocline in the Amundsen basin was always present and rather stable over the three time periods. In contrast, the Canada and Makarov basins' halocline became more stratified during the IPY than before, mainly because of surface water freshening. In addition, observations also confirmed the importance of the halocline thickness for controlling the stratification variability. Observations suggest that both large scale and small scale processes affect the halocline. Changes in surface salinity observed in the Makarov basin are more likely due to atmospheric variability (AO, Dipole Anomaly), as previously observed. More locally, some observations point out that salt/heat diffusion from the Atlantic water underneath and brine rejection during sea ice formation from above could be responsible for salt content variability within the halocline and, as a consequence, being influential for the variability of the halocline. In spite of the existence of interannual variability, the Arctic Ocean main stratification, characterized by a stable and robust halocline until now, suggested that the deep ocean had a limited impact on the mixed layer and on sea ice in actual conditions. The drastic changes observed in Arctic sea ice during this period (1997-2008) cannot be attributed to a weakening of the halocline that could trigger an enhanced vertical heat flux from the deep ocean. 相似文献
5.
基于Hough变换原理的海冰厚度识别方法 总被引：1，自引：1，他引：0
作为主要海冰参数之一的海冰厚度对海冰灾害评估和极地船舶与冰区海洋工程结构设计具有重要意义。采用船侧视频图像对海冰厚度进行自动识别是提取海冰参数的重要方式。本文采用基于Hough变换的机器视觉方法对海冰翻转过程中的表面轮廓线进行识别,从而自动获取海冰厚度参数。根据海冰图像特征制定了图像边缘识别?近似线段识别?海冰轮廓线段组识别的计算流程。在线段组识别过程中,根据海冰的几何特征建立了由夹角、长度及间距参数相关联的3个识别参数所组成的判断条件。为验证方法的可靠性,将该方法用于“雪龙”号第八次北极科考的走航实测数据中,结果表明,3个识别参数均具有最优阈值。当低于最优值时提高阈值可增加有效识别率;而高于最优值时提高阈值则会导致误判率增大,采用最优阈值可使冰厚识别率达到90%以上。因此,采用基于Hough变换的冰厚识别方法可实现对海冰厚度的实时监测。 相似文献
6.
《Marine Policy》2017
The rapid Arctic summer sea ice reduction in the last decade has lead to debates in the maritime industries on the possibility of an increase in cargo transportation in the region. Average sailing times on the North Sea Route along the Siberian Coast have fallen from 20 days in the 1990s to 11 days in 2012–2013, attributed to easing sea ice conditions along the Siberian coast. However, the economic risk of exploiting the Arctic shipping routes is substantial. Here a detailed high-resolution projection of ocean and sea ice to the end of the 21st century forced with the RCP8.5 IPCC emission scenario is used to examine navigability of the Arctic sea routes. In summer, opening of large areas of the Arctic Ocean previously covered by pack ice to the wind and surface waves leads to Arctic pack ice cover evolving into the Marginal Ice Zone. The emerging state of the Arctic Ocean features more fragmented thinner sea ice, stronger winds, ocean currents and waves. By the mid 21st century, summer season sailing times along the route via the North Pole are estimated to be 13–17 days, which could make this route as fast as the North Sea Route. 相似文献
7.
北极冬季季节性海冰双模态特征分析 总被引：1，自引：1，他引：0
近年来北极海冰快速变化,北极中央区边缘正由以多年冰为主转为季节性海冰为主。通过对北极冬季季节性海冰的EOF分解发现,2002-2012年期间北极季节性海冰变化的前两模态主要体现为2005年和2007年的季节性海冰距平。其中第二模态主要体现了北极海冰在2005年的一种极端变化,而第一模态不仅体现了北极海冰在2007年的变化,还体现了北极季节性海冰的从负位相到正位相的转变。通过比较发现,在研究时段北极季节性海冰最主要的变化发生在北极太平洋扇区,在2007年,冬季季节性海冰距平发生位相转变,2007-2010年一直维持正位相,北极太平洋扇区冬季季节性海冰保持显著正距平。太平洋扇区表面温度最大异常也发生在2007年,从大气环流来看,2007年之后波弗特海区异常高压有利于夏季太平洋扇区海冰的减少,而西风急流的减弱有利于夏季波弗特海区异常高压的维持,结合夏季海冰速度,顺时针的冰速分布有利于海冰离开太平洋扇区,因而会导致冬季太平洋扇区季节性海冰转为正距平并且从2007年一直维持到2010年。 相似文献
8.
Interaction of an anticyclonic eddy with sea ice in the western Arctic Ocean: an eddy-resolving model study 总被引：1，自引：0，他引：1
The dramatic decline of summer sea ice extent and thickness has been witnessed in the western Arctic Ocean in recent decades, which hasmotivated scientists to search for possible factors driving the sea ice variability. An eddy-resolving, ice-ocean coupled model covering the entire Arctic Ocean is implemented, with focus on the western Arctic Ocean. Special attention is paid to the summer Alaskan coastal current (ACC), which has a high temperature (up to 5℃ ormore) in the upper layer due to the solar radiation over the open water at the lower latitude. Downstream of the ACC after Barrow Point, a surface-intensified anticyclonic eddy is frequently generated and propagate towards the Canada Basin during the summer season when sea ice has retreated away from the coast. Such an eddy has a warm core, and its source is high-temperature ACC water. A typical warm-core eddy is traced. It is trapped just below summer sea ice melt water and has a thickness about 60 m. Temperature in the eddy core reaches 2-3℃, and most water inside the eddy has a temperature over 1℃. With a definition of the eddy boundary, an eddy heat is calculated, which can melt 1 600 km2 of 1mthick sea ice under extreme conditions. 相似文献
9.
《Ocean Modelling》2001,3(1-2):127-135
The high-latitude freezing and melting cycle can variously result in haline convection, freshwater capping or freshwater injection into the interior ocean. An example of the latter process is a secondary salinity minimum near 800 m-depth within the Arctic Ocean that results from the transformation on the Barents Sea shelf of Atlantic water from the Norwegian Sea and its subsequent intrusion into the Arctic Ocean. About one-third of the freshening on the shelf of that initially saline water appears to result from ice melt, although the actual sea ice flux is small, only about 0.005 Sv. A curious feature of this process is that water distilled at the surface of the Arctic Ocean by freezing ends up at mid-depth in the same ocean. This is a consequence of the ice being exported southward onto the shelf, melted, and then entrained into the northward Barents Sea throughflow that subsequently sinks into the Arctic Ocean. Prolonged reduction in sea ice in the region and in the concomitant freshwater injection would likely result in a warmer and more saline interior Arctic Ocean below 800 m. 相似文献
10.
基于CryoSat-2数据的2010-2017年北极海冰厚度和体积的季节与年际变化特征 总被引：2，自引：2，他引：0
北极海冰变化影响着全球物质平衡、能量交换和气候变化。本文基于CryoSat-2测高数据和OSI SAF海冰密集度及海冰类型产品，分析了2010-2017年北极海冰面积、厚度和体积的季节和年际变化特征，结合NCEP再分析资料探讨了融冰期北极气温异常和夏季风异常对海冰变化的影响。结果表明，结冰期海冰面积的增加量波动较大，海冰厚度的增加量呈明显下降趋势。融冰期海冰厚度的减小量波动较大，2013年以后融冰期海冰面积的减小量逐年增加。海冰体积的变化趋势和面积变化更相似，融冰期的减小速率大于结冰期的增加速率。融冰期北极海表面大气温度异常与海冰融化量正相关。夏季风影响海冰的辐合和辐散，在弗拉姆海峡海冰的输运过程中起关键作用，促进了北冰洋表层水向大洋深层的传输。 相似文献
11.
Climate change presages increasingly ice-free waters in the Canadian Arctic and fundamental reconfiguration of Asia–Europe and Asia–US East Coast marine transportation networks via the Northwest Passage (NWP). Retreating sea ice will impact the annual re-supply of goods to northern communities, natural resource development, cruise ship and adventure tourism activity, and the fishing industry. Reviews of infrastructure to support increased shipping activity and support future developments highlight an ageing Canadian Coast Guard (CCG) icebreaker fleet. This paper aims to debate the need for, and provision, ownership and management of Arctic icebreaking services required to serve a NWP. It reports perceptions by 110 experts of future marine activity in the Canadian Arctic and CCG services, principally Arctic icebreaking, in terms of their effectiveness and efficiency. The extent of possible private involvement is identified and evaluated. The requirements needed to ensure timely and uninterrupted marine transportation from vessels operating in these waters are highlighted. 相似文献
12.
北极地区不同冰龄的海冰厚度变化研究 总被引：1，自引：0，他引：1
In this study, changes in Arctic sea ice thickness for each ice age category were examined based on satellite observations and modelled results. Interannual changes obtained from Ice, Cloud, and Land Elevation Satellite(ICESat)-based results show a thickness reduction over perennial sea ice(ice that survives at least one melt season with an age of no less than 2 year) up to approximately 0.5–1.0 m and 0.6–0.8 m(depending on ice age) during the investigated winter and autumn ICESat periods, respectively. Pan-Arctic Ice Ocean Modeling and Assimilation System(PIOMAS)-based results provide a view of a continued thickness reduction over the past four decades. Compared to 1980 s, there is a clear thickness drop of roughly 0.50 m in 2010 s for perennial ice. This overall decrease in sea ice thickness can be in part attributed to the amplified warming climate in north latitudes. Besides, we figure out that strongly anomalous southerly summer surface winds may play an important role in prompting the thickness decline in perennial ice zone through transporting heat deposited in open water(primarily via albedo feedback) in Eurasian sector deep into a broader sea ice regime in central Arctic Ocean. This heat source is responsible for enhanced ice bottom melting, leading to further reduction in ice thickness. 相似文献
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14.
本文利用1951?2021年哈德莱中心提供的海冰和海温最新资料以及美国国家海洋和大气管理局气候预报中心提供的NCEP/NCAR再分析资料,分析探讨了北极海冰70余年的长期变化特征,进而研究了其快速减少与热带海温场异常变化之间的联系,揭示了在全球热带海洋海温场变化与北极海冰之间存在密切联系的事实。结果表明,北极海冰异常变化最显著区域出现在格陵兰海、卡拉海和巴伦支海。热带不同海区对北极海冰的影响存在明显时滞时间和强度差异,热带大西洋的影响相比偏早,印度洋次之,太平洋偏晚。热带大西洋、印度洋和中东太平洋海温异常影响北极海冰的最佳时间分别是后者滞后26个月、30个月和34个月,全球热带海洋影响北极海冰的时滞时间为33个月。印度洋SST对北极海冰的影响程度最强,其次是太平洋,最弱是大西洋。全球热带海洋对北极海冰的影响过程中,热带东太平洋和印度洋起主导作用。当全球热带海洋SST出现正（负）距平时,北极海冰会出现偏少（多）的趋势,而AO、PNA、NAO对北极海冰变化起重要作用,是热带海洋与北极海冰相系数的重要“纽带”。而AO、PNA和NAO不仅受热带海洋SST的影响,同时也受太平洋年代际振荡PDO和大西洋多年代际AMO的影响,这一研究为未来北极海冰快速减少和全球气候变暖机理的深入研究提供理论支撑。 相似文献
15.
Marika Marnela Bert Rudels K. Anders Olsson Leif G. Anderson Daniel J. Torres James H. Swift 《Progress in Oceanography》2008,78(1):1-11
To determine the exchanges between the Nordic Seas and the Arctic Ocean through Fram Strait is one of the most important aspects, and one of the major challenges, in describing the circulation in the Arctic Mediterranean Sea. Especially the northward transport of Arctic Intermediate Water (AIW) from the Nordic Seas into the Arctic Ocean is little known. In the two-ship study of the circulation in the Nordic Seas, Arctic Ocean - 2002, the Swedish icebreaker Oden operated in the ice-covered areas in and north of Fram Strait and in the western margins of Greenland and Iceland seas, while RV Knorr of Woods Hole worked in the ice free part of the Nordic Seas. Here two hydrographic sections obtained by Oden, augmented by tracer and velocity measurements with Lowered Acoustic Doppler Current Profiler (LADCP), are examined. The first section, reaching from the Svalbard shelf across the Yermak Plateau, covers the region north of Svalbard where inflow to the Arctic Ocean takes place. The second, western, section spans the outflow area extending from west of the Yermak Plateau onto the Greenland shelf. Geostrophic and LADCP derived velocities are both used to estimate the exchanges of water masses between the Nordic Seas and the Arctic Ocean. The geostrophic computations indicate a total flow of 3.6 Sv entering the Arctic on the eastern section. The southward flow on the western section is found to be 5.1 Sv. The total inflow to the Arctic Ocean obtained using the LADCP derived velocities is much larger, 13.6 Sv, and the southward transport on the western section is 13.7 Sv, equal to the northward transport north of Svalbard. Sulphur hexafluoride (SF6) originating from a tracer release experiment in the Greenland Sea in 1996 has become a marker for the circulation of AIW. From the geostrophic velocities we obtain 0.5 Sv and from the LADCP derived velocities 2.8 Sv of AIW flowing into the Arctic. The annual transport of SF6 into the Arctic Ocean derived from geostrophy is 5 kg/year, which is of the same magnitude as the observed total annual transport into the North Atlantic, while the LADCP measurements (19 kg/year) imply that it is substantially larger. Little SF6 was found on the western section, confirming the dominance of the Arctic Ocean water masses and indicating that the major recirculation in Fram Strait takes place farther to the south. 相似文献
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17.
Qi Shu Fangli Qiao Jiping Liu Zhenya Song Zhiqiang Chen Jiechen Zhao Xunqiang Yin Yajuan Song 《海洋学报(英文版)》2021,40(10):65-75
To improve the Arctic sea ice forecast skill of the First Institute of Oceanography-Earth System Model (FIO-ESM) climate forecast system, satellite-derived sea ice concentration and sea ice thickness from the Pan-Arctic Ice-Ocean Modeling and Assimilation System (PIOMAS) are assimilated into this system, using the method of localized error subspace transform ensemble Kalman ?lter (LESTKF). Five-year (2014–2018) Arctic sea ice assimilation experiments and a 2-month near-real-time forecast in August 2018 were conducted to study the roles of ice data assimilation. Assimilation experiment results show that ice concentration assimilation can help to get better modeled ice concentration and ice extent. All the biases of ice concentration, ice cover, ice volume, and ice thickness can be reduced dramatically through ice concentration and thickness assimilation. The near-real-time forecast results indicate that ice data assimilation can improve the forecast skill significantly in the FIO-ESM climate forecast system. The forecasted Arctic integrated ice edge error is reduced by around 1/3 by sea ice data assimilation. Compared with the six near-real-time Arctic sea ice forecast results from the subseasonal-to-seasonal (S2S) Prediction Project, FIO-ESM climate forecast system with LESTKF ice data assimilation has relatively high Arctic sea ice forecast skill in 2018 summer sea ice forecast. Since sea ice thickness in the PIOMAS is updated in time, it is a good choice for data assimilation to improve sea ice prediction skills in the near-real-time Arctic sea ice seasonal prediction. 相似文献
18.
Mikhalevsky P.N. Gavrilov A.N. Baggeroer A.B. 《Oceanic Engineering, IEEE Journal of》1999,24(2):183-201
In April 1994, coherent acoustic transmissions were propagated across the entire Arctic basin for the first time. This experiment, known as the Transarctic Acoustic Propagation Experiment (TAP), was designed to determine the feasibility of using these signals to monitor changes in Arctic Ocean temperature and changes in sea ice thickness and concentration. CW and maximal length sequences (MLS) were transmitted from the source camp located north of the Svalbard Archipelago 1000 km to a vertical line array in the Lincoln Sea and 2600 km to a two-dimensional horizontal array and a vertical array in the Beaufort Sea. TAP demonstrated that the 19.6-Hz 195-dB (251-W) signals propagated with both sufficiently low loss and high phase stability to support the coherent pulse compression processing of the MLS and the phase detection of the CW signals. These yield time delay measurements an order of magnitude better than what is required to detect the estimated 80-ms/year changes in travel time caused by interannual and longer term changes in Arctic Ocean temperature. The TAP data provided propagation loss measurements to compare with the models to be used for correlating modal scattering losses with sea ice properties for ice monitoring. The travel times measured in TAP indicated a warming of the Atlantic layer in the Arctic of close to 0.4°C, which has been confirmed by direct measurement from icebreakers and submarines, demonstrating the utility of acoustic thermometry in the Arctic. The unique advantages of acoustic thermometry in the Arctic and the importance of climate monitoring in the Arctic are discussed. A four-year program, Arctic Climate Observations using Underwater Sound is underway to carry out the first installations of sources and receivers in the Arctic Ocean 相似文献
19.
In 1979, the General Bathymetric Chart of the Oceans (GEBCO) published Sheet 5.17 in the Fifth Edition of its series of global
bathymetric maps. Sheet 5.17 covered the northern polar region above 64° N, and was for long the authoritative portrayal of
Arctic bathymetry. The GEBCO compilation team had access to an extremely sparse sounding database from the central Arctic
Ocean, due to the difficulty of mapping in this permanently ice covered region. In the past decade, there has been a substantial
increase in the database of central Arctic Ocean bathymetry, due to the declassification of sounding data collected by US
and British Navy nuclear submarines, and to the capability of modern icebreakers to measure ocean depths in heavy ice conditions.
From these data sets, evidence has mounted to indicate that many of the smaller (and some larger) bathymetric features of
Sheet 5.17 were poorly or wrongly defined. Within the framework of the project to construct the International Bathymetric
Chart of the Arctic Ocean (IBCAO), all available historic and modern data sets were compiled to create a digital bathymetric
model. In this paper, we compare both generally and in detail the contents of GEBCO Sheet 5.17 and version 1.0 of IBCAO, two
bathymetric portrayals that were created more than 20 years apart. The results should be helpful in the analysis and assessment
of previously published studies that were based on GEBCO Sheet 5.17.
Ron Macnab: Retired. 相似文献
20.
全球碳增汇需求高涨,海冰消退后的北冰洋被期待是一个主要的潜在碳增汇区。北冰洋太平洋扇区因受控于楚科奇海及其邻近海域较高的海洋固碳效率和碳深海封存量,在整个北冰洋碳循环中起着举足轻重的作用。开展该海域碳循环过程对环境快速变化的响应机制研究是实现北冰洋碳汇精准预测的基础。本文重点阐述了楚科奇海及其邻近海域碳循环过程（即海洋对大气二氧化碳的吸收、生物固碳、太平洋入流携带碳经陆架生物地化过程后向深海输出封存的陆架泵）对北冰洋环境快速变化的响应,并提出未来研究需要聚焦的关键科学问题。 相似文献