Aerial observations of the evolution of ice surface conditions during summer
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In the summer of 1998, a program of aerial photography was carried out at the main site of the Surface Heat Budget of the Arctic Ocean (SHEBA) program at altitudes ranging from 1220 to 1830 m as mentioned in this paper.Abstract:
[1] During spring and summer, the Arctic pack ice cover undergoes a dramatic change in surface conditions, evolving from a uniform, reflective surface to a heterogeneous mixture of bare ice, melt ponds, and leads. This transformation is accompanied by a significant decrease in areally averaged, integrated albedo. The key factors contributing to this reduction in albedo are the melting of the snow cover, the formation and growth of the melt ponds, and the increase in the open water fraction. To document these changes and enable quantification of the evolution of the ponds throughout the melt season, a program of aerial photography was carried out at the main site of the Surface Heat Budget of the Arctic Ocean (SHEBA) program. A modified square pattern, 50 km on a side, surrounding the SHEBA site was flown at altitudes ranging from 1220 to 1830 m. Twelve of these aerial survey photography flights were completed between 20 May and 4 October 1998. The flights took place at approximately weekly intervals at the height of the melt season, with occasional gaps as long as 3 weeks during August and September due to persistent low clouds and fog. In addition, flights on 17 May and 25 July were flown in a closely spaced pattern designed to provide complete photo coverage of a 10-km square centered on the SHEBA main site. Images from all flights were scanned at high resolution and archived on CD-ROMs. Using personal computer image processing software, we have measured ice concentration, melt pond coverage, statistics on size and shape of melt ponds, lead fraction, and lead perimeter for the summer melt season. The ponds began forming in early June, and by the height of the melt season in early August the pond fraction exceeded 0.20. The temporal evolution of pond fraction displayed a rapid increase in mid-June, followed by a sharp decline 1 week later. After the decline, the pond fraction gradually increased until mid-August when the ponds began to freeze. By mid-September the surface of virtually all of the ponds had frozen. The open water fraction varied between 0.02 and 0.05 from May through the end of July. In early August the open water fraction jumped to 0.20 in just a few days owing to ice divergence. Melt ponds were ubiquitous during summer, with number densities increasing from 1000 to 5000 ponds per square kilometer between June and August.read more
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Journal ArticleDOI
Surface Heat Budget of the Arctic Ocean
Taneil Uttal,Judith A. Curry,Miles G. McPhee,Donald K. Perovich,Richard E. Moritz,James A. Maslanik,Peter S. Guest,Harry L. Stern,James A. Moore,Rene Turenne,Andreas Heiberg,Mark C. Serreze,Donald P. Wylie,Ola Persson,Clayton A. Paulson,Christopher Halle,James H. Morison,Patricia A. Wheeler,Alexander Makshtas,Harold Welch,Matthew D. Shupe,Janet M. Intrieri,Knut Stamnes,Ronald W. Lindsey,Robert Pinkel,W. Scott Pegau,Timothy P. Stanton,Thomas C. Grenfeld +27 more
TL;DR: The Surface Heat Budget of the Arctic Ocean (SHEBA) project as discussed by the authors collected ocean, ice, and atmospheric datasets over a full annual cycle that could be used to understand the processes controlling surface heat exchanges.
Journal ArticleDOI
Seasonal evolution of the albedo of multiyear Arctic sea ice
TL;DR: In this article, the spectral and wavelength-integrated albedo on multi-year sea ice was measured every 2.5 m along a 200m survey line from April through October.
Journal Article
Seasonal evolution of the albedo of multiyear Arctic sea ice : The surface heat budget of arctic ocen (SHEBA)
TL;DR: In this paper, the authors measured spectral and wavelength-integrated albedo on multi-year sea ice from a 200m survey line from April through October and observed changes in the evolution of albedos.
Journal ArticleDOI
Albedo evolution of seasonal Arctic sea ice
TL;DR: In this paper, the authors examined the impact of seasonal ice cover on sea ice albedo and found that the shift from a multi-year to seasonal cover has significant implications for the heat and mass budget of the ice and for primary productivity in the upper ocean.
Journal ArticleDOI
Improved sea ice shortwave radiation physics in CCSM4: The impact of melt ponds and aerosols on Arctic Sea ice
TL;DR: The Community Climate System Model, version 4 has revisions across all components and the most notable improvements are the incorporation of a new shortwave radiative transfer scheme and the capabilities that this enables.
References
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Journal ArticleDOI
Year on ice gives climate insights
Donald K. Perovich,Edgar L. Andreas,Judith A. Curry,H. Eiken,Christopher W. Fairall,Thomas C. Grenfell,Peter S. Guest,Janet M. Intrieri,David Kadko,Ron Lindsay,Miles G. McPhee,James H. Morison,Richard E. Moritz,Clayton A. Paulson,W.S. Pegau,P. O. G. Persson,Robert Pinkel,Jacqueline A. Richter-Menge,Timothy P. Stanton,Harry L. Stern,Matthew Sturm,Walter B. Tucker,Taneil Uttal +22 more
TL;DR: The Surface Heat Budget of the Arctic Ocean (SHEBA) project as mentioned in this paper was not motivated by climate change, and it was not designed to detect global warming, nor was it designed to diagnose global warming.
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The role of sea ice in 2 x CO2 climate model sensitivity. Part 1: The total influence of sea ice thickness and extent
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The Arctic sea ice-climate system: observations and modeling
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Freshening of the upper ocean in the Arctic: Is perennial sea ice disappearing?
TL;DR: During the Surface Heat Budget of the Arctic (SHEBA) deployment in October, 1997, multiyear ice near the center of the Beaufort Gyre was anomalously thin this article.