Impact of Sea Ice Compression on Navigation Performance

Author(s):  
Genki Sagawa

Ship navigation performance in the Arctic ice-covered sea was investigated from various kinds of satellite data and a numerical model of sea ice. The effect of dynamical processes of ice on the performance was especially examined, for it was not focused enough in previous studies. As a result, it was found that ice stress can explain some parts of the navigation when high amount of speed reduction occurred in thin ice area, and vice versa. The result indicates an importance of considering dynamical processes of ice in addition to static condition of ice, to improve an accuracy of an ice navigation performance estimation.

2002 ◽  
Vol 34 ◽  
pp. 420-428 ◽  
Author(s):  
Josefino C. Comiso

AbstractCo-registered and continuous satellite data of sea-ice concentrations and surface ice temperatures from 1981 to 2000 are analyzed to evaluate relationships between these two critical climate parameters and what they reveal in tandem about the changing Arctic environment. During the 19 year period, the Arctic ice extent and actual ice area are shown to be declining at a rate of –2.0±0.3% dec –1 and 3.1 ±0.4% dec–1, respectively, while the surface ice temperature has been increasing at 0.4 ±0.2 K dec–1, where dec is decade. The extent and area of the perennial ice cover, estimated from summer minimum values, have been declining at a much faster rate of –6.7±2.4% dec–1 and –8.3±2.4% dec–1, respectively, while the surface ice temperature has been increasing at 0.9 ±0.6K dec–1. This unusual rate of decline is accompanied by a very variable summer ice cover in the 1990s compared to the 1980s, suggesting increases in the fraction of the relatively thin second-year, and hence a thinning in the perennial, ice cover during the last two decades. Yearly anomaly maps show that the ice-concentration anomalies are predominantly positive in the 1980s and negative in the 1990s, while surface temperature anomalies were mainly negative in the 1980s and positive in the 1990s. The yearly ice-concentration and surface temperature anomalies are highly correlated, indicating a strong link especially in the seasonal region and around the periphery of the perennial ice cover. The surface temperature anomalies also reveal the spatial scope of each warming (or cooling) phenomenon that usually extends beyond the boundaries of the sea-ice cover.


2018 ◽  
Author(s):  
John E. Walsh ◽  
J. Scott Stewart ◽  
Florence Fetterer

Abstract. Basic statistical metrics such as autocorrelations and across-region lag correlations of sea ice variations provide benchmarks for the assessments of forecast skill achieved by other methods such as more sophisticated statistical formulations, numerical models, and heuristic approaches. However, the strong negative trend of sea ice coverage in recent decades complicates the evaluation of statistical skill by inflating the correlation of interannual variations of pan-Arctic and regional ice extent. In this study we provide a quantitative evaluation of the contribution of the trend to the predictive skill of monthly and seasonal ice extent on the pan-Arctic and regional scales. We focus on the Beaufort Sea where the Barnett Severity Index provides a metric of historical variations in ice conditions over the summer shipping season. The variance about the trend line differs little among various methods of detrending (piecewise linear, quadratic, cubic, exponential). Application of the piecewise linear trend calculation indicates an acceleration of the trend during the 1990s in most of the Arctic subregions. The Barnett Severity Index as well as September pan-Arctic ice extent show significant statistical predictability out to several seasons when the data include the trend. However, this apparent skill largely vanishes when the data are detrended. No region shows significant correlation with the detrended September pan-Arctic ice extent at lead times greater than a month or two; the concurrent correlations are strongest with the East Siberian Sea. The Beaufort Sea’s ice extent as far back as July explains about 20 % of the variance of the Barnett Severity Index, which is primarily a September metric. The Chukchi Sea is the only other region showing a significant association with the Barnett Severity Index, although only at a lead time of a month or two.


2021 ◽  
Author(s):  
Alek Petty ◽  
Nicole Keeney ◽  
Alex Cabaj ◽  
Paul Kushner ◽  
Nathan Kurtz ◽  
...  

<div> <div> <div> <div> <p>National Aeronautics and Space Administration's (NASA's) Ice, Cloud, and land Elevation Satellite‐ 2 (ICESat‐2) mission was launched in September 2018 and is now providing routine, very high‐resolution estimates of surface height/type (the ATL07 product) and freeboard (the ATL10 product) across the Arctic and Southern Oceans. In recent work we used snow depth and density estimates from the NASA Eulerian Snow on Sea Ice Model (NESOSIM) together with ATL10 freeboard data to estimate sea ice thickness across the entire Arctic Ocean. Here we provide an overview of updates made to both the underlying ATL10 freeboard product and the NESOSIM model, and the subsequent impacts on our estimates of sea ice thickness including updated comparisons to the original ICESat mission and ESA’s CryoSat-2. Finally we compare our Arctic ice thickness estimates from the 2018-2019 and 2019-2020 winters and discuss possible causes of these differences based on an analysis of atmospheric data (ERA5), ice drift (NSIDC) and ice type (OSI SAF).</p> </div> </div> </div> </div>


2020 ◽  
Author(s):  
Michelle Koutnik ◽  
Nadine Fabbi ◽  
Elizabeth Wessells ◽  
Ellen Ahlness ◽  
Max Showalter ◽  
...  

<p>With the Arctic currently warming at a rate at least twice that of the global average, the coupled Arctic ecosystem is losing ice. This includes significant land-ice loss from the Greenland Ice Sheet and Arctic ice caps and glaciers, reduction in extent and thickness of Arctic sea ice, and thawing permafrost. This scale of environmental change significantly affects Arctic people, wildlife, infrastructure, transportation, and access. Societal response to these changes relies on advances in and application of research spanning multiple scientific disciplines, with policy-making done in partnership with Indigenous people, governments, private agencies, multinational corporations, and other interested groups. Everyone will interface with outcomes due to a changing climate and the challenge is mounting for the next generation of leaders. The cross-disciplinary nature of the challenge of Arctic ice loss and climate change must be met by cross-disciplinary undergraduate education. While higher education aims for disciplinary training in natural sciences and social sciences, there is an increasing responsibility to integrate topics and immerse students in real-world issues. And, in our experience the undergraduates we teach are eager for courses that can do this well.</p><p>What is immersive undergraduate education? We consider this as either immersing students in a focused topic in the classroom, immersing students in a place (especially while abroad), or combining the two through targeted lectures, informed discussions, travel, and writing. With regard to the Arctic, it is necessary to bring scientific understanding to learning activities otherwise focused on societal impacts, policy making, and knowledge exchange through public writing.</p><p>We share from our practical experience teaching Arctic-focused courses to classes each with 10-30 students with majors from across the University of Washington (UW) campus (total undergraduate student body of 32,000). Three recent activities that integrate the state of science with impacts on society in undergraduate courses include: 1) a four-week study abroad course to Greenland and Denmark focusing on changes in the Greenland Ice Sheet and sea-level rise, 2) a 10-week Task Force course in Arctic Sea Ice and International Policy in partnership with the UW International Policy Institute at the Henry M. Jackson School of International Studies that includes one-week in Ottawa where students develop a mock Arctic sea ice policy for Canada consistent with Inuit priorities, and 3) a 10-week seminar in public writing where students write mock newspaper articles, book reviews, and policy summaries about ice in a changing climate. These courses were designed to include a similar subset of earth science, atmospheric science, and oceanography, but the distinct structure and application of the science in these three separate courses led to distinct learning outcomes. In addition, we present how the academic minor in Arctic Studies at the University of Washington has allowed students to design their own integrated understanding of Indigenous and nation-state Arctic geopolitics, Arctic environmental change, and policy by taking a selection of courses and engaging in research and report writing.</p>


2020 ◽  
Author(s):  
Kent Moore ◽  
Stephen Howell ◽  
Mike Brady ◽  
Xiaoyong Xu ◽  
Kaitlin McNeil

<p>The ice arches that usually develop at the northern and southern ends of Nares Strait play an important role in modulating the export of multi-year sea ice out of the Arctic Ocean.   As a result of global warming, the Arctic Ocean is evolving towards an ice pack that is younger, thinner and more mobile and the fate of its multi-year ice is becoming of increasing interest to both the scientific and policy communities.  Here, we use sea ice motion retrievals derived from Sentinel-1 imagery to report on recent behaviour of these ice arches and the associated ice flux. In addition to the previously identified early collapse of the northern ice arch in May 2017, we report that this arch failed to develop during the winters of 2018 and 2019.  In contrast, we report that the southern ice arch was only present for a short period of time during the winter of 2018.  We also show that the duration of arch formation has decreased over the past 20 years as ice in the region has thinned, while the ice area and volume fluxes have both increased.  These results suggest that a transition is underway towards a state where the formation of these arches will become atypical with a concomitant increase in the export of multi-year ice accelerating the transition towards a younger and thinner Arctic ice pack.</p>


2011 ◽  
Vol 47 (6) ◽  
pp. 794-794
Author(s):  
S. N. Moshonkin ◽  
G. V. Alekseev ◽  
N. A. Dianskii ◽  
A. V. Gusev ◽  
V. B. Zalesny

1997 ◽  
Vol 102 (C9) ◽  
pp. 21061-21079 ◽  
Author(s):  
Michael Steele ◽  
Jinlun Zhang ◽  
Drew Rothrock ◽  
Harry Stern

2021 ◽  
Author(s):  
Shahram Sattar

Conventional ice navigation through sea ice is manually operated by well-trained navigators, whose experiences are heavily relied upon to guarantee the ship's safety. Despite increasingly available ice data and information, little has been done to develop automatic ice navigation systems to better guide ships in sea ice. In this study firstly navigable sea areas for different types of ships were identified according to the navigation codes in northern regions. Secondly, three algorithms of path planning were adopted to automatically compute the safest-and-shortest ship routes based on the concepts of the Voronoi diagram, Visibility graph, and Visibility-Voronoi diagram, respectively. These algorithms and results were compared and evaluated in terms of different application scenarios. Results show that the Visibility-Voronoi approach seems to be the best viable solution in terms of computing performance and navigation safety. The work will provide a basis for further development towards an automatic ice navigation support system


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