Route-specific ice thickness distribution in the Arctic Ocean during a North Pole crossing in August 1990

Abstract The minimum of Arctic sea ice extent in the summer of 2007 was unprecedented in the historical record. A coupled ice–ocean model is used to determine the state of the ice and ocean over the past 29 yr to investigate the causes of this ice extent minimum within a historical perspective. It is found that even though the 2007 ice extent was strongly anomalous, the loss in total ice mass was not. Rather, the 2007 ice mass loss is largely consistent with a steady decrease in ice thickness that began in 1987. Since then, the simulated mean September ice thickness within the Arctic Ocean has declined from 3.7 to 2.6 m at a rate of −0.57 m decade−1. Both the area coverage of thin ice at the beginning of the melt season and the total volume of ice lost in the summer have been steadily increasing. The combined impact of these two trends caused a large reduction in the September mean ice concentration in the Arctic Ocean. This created conditions during the summer of 2007 that allowed persistent winds to push the remaining ice from the Pacific side to the Atlantic side of the basin and more than usual into the Greenland Sea. This exposed large areas of open water, resulting in the record ice extent anomaly.

Download Full-text

Simulation of Snow on Arctic Sea Ice Using a Coupled Snow–Ice Model

Journal of Hydrometeorology ◽

10.1175/2009jhm1112.1 ◽

2010 ◽

Vol 11 (1) ◽

pp. 199-210 ◽

Cited By ~ 10

Author(s):

Yi-Ching Chung ◽

Stéphane Bélair ◽

Jocelyn Mailhot

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Snow Depth ◽

Single Layer ◽

Coupled System ◽

The Arctic ◽

Ice Thickness ◽

The Arctic Ocean ◽

Snow Model ◽

Ice Model

Abstract The new Recherche Prévision Numérique (NEW-RPN) model, a coupled system including a multilayer snow thermal model (SNTHERM) and the sea ice model currently used in the Meteorological Service of Canada (MSC) operational forecasting system, was evaluated in a one-dimensional mode using meteorological observations from the Surface Heat Budget of the Arctic Ocean (SHEBA)’s Pittsburgh site in the Arctic Ocean collected during 1997/98. Two parameters simulated by NEW-RPN (i.e., snow depth and ice thickness) are compared with SHEBA’s observations and with simulations from RPN, MSC’s current coupled system (the same sea ice model and a single-layer snow model). Results show that NEW-RPN exhibits better agreement for the timing of snow depletion and for ice thickness. The profiles of snow thermal conductivity in NEW-RPN show considerable variability across the snow layers, but the mean value (0.39 W m−1 K−1) is within the range of reported observations for SHEBA. This value is larger than 0.31 W m−1 K−1, which is commonly used in single-layer snow models. Of particular interest in NEW-RPN’s simulation is the strong temperature stratification of the snowpack, which indicates that a multilayer snow model is needed in the SHEBA scenario. A sensitivity analysis indicates that snow compaction is also a crucial process for a realistic representation of the snowpack within the snow/sea ice system. NEW-RPN’s overestimation of snow depth may be related to other processes not included in the study, such as small-scale horizontal variability of snow depth and blowing snow processes.

Download Full-text

On the Response of the Equilibrium Thickness Distribution of Sea Ice to Ice Export, Mechanical Deformation, and Thermal Forcing With Application to the Arctic Ocean

Journal of Geophysical Research Atmospheres ◽

10.1029/92jc00814 ◽

1992 ◽

Vol 97 (C7) ◽

pp. 11287-11298 ◽

Cited By ~ 27

Author(s):

Göran Björk

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Thickness Distribution ◽

Mechanical Deformation ◽

The Arctic ◽

Thermal Forcing ◽

The Arctic Ocean ◽

Equilibrium Thickness

Download Full-text

Desecuritization as Displacement of Controversy: geopolitics, law and sovereign rights in the Arctic

Politik ◽

10.7146/politik.v20i3.97151 ◽

2017 ◽

Vol 20 (3) ◽

Cited By ~ 1

Author(s):

Marc Jacobsen ◽

Jeppe Strandsbjerg

Keyword(s):

Arctic Ocean ◽

International Law ◽

Indigenous Peoples ◽

North Pole ◽

The Other ◽

The Arctic ◽

The Arctic Ocean ◽

Securitization Theory ◽

The Media ◽

The One

By signing the Ilulissat Declaration of May 2008, the five littoral states of the Arctic Ocean pre-emptively desecuritized potential geopolitical controversies in the Arctic Ocean by confirming that international law and geo-science are the defining factors underlying the future delimitation. This happened in response to a rising securitization discourse fueled by commentators and the media in the wake of the 2007 Russian flag planting on the geographical North Pole seabed, which also triggered harder interstate rhetoric and dramatic headlines. This case, however, challenges some established conventions within securitization theory. It was state elites that initiated desecuritization and they did so by shifting issues in danger of being securitized from security to other techniques of government. Contrary to the democratic ethos of the theory, these shifts do not necessarily represent more democratic procedures. Instead, each of these techniques are populated by their own experts and technocrats operating according to logics of right (law) and accuracy (science). While shifting techniques of government might diminish the danger of securitized relations between states, the shift generates a displacement of controversy. Within international law we have seen controversy over its ontological foundations and within science we have seen controversy over standards of science. Each of these are amplified and take a particularly political significance when an issue is securitized via relocation to another technique. While the Ilulissat Declaration has been successful in minimizing the horizontal conflict potential between states it has simultaneously given way for vertical disputes between the signatory states on the one hand and the Indigenous peoples of the Arctic on the other.

Download Full-text

Interpretation of Slar Imagery of Sea Ice in Nares Strait and the Arctic Ocean

Journal of Glaciology ◽

10.3189/s0022143000034377 ◽

1975 ◽

Vol 15 (73) ◽

pp. 193-213

Author(s):

Moira Dunbar

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

North Pole ◽

The Arctic ◽

Canadian Forces ◽

Nares Strait ◽

The North ◽

The Arctic Ocean ◽

Ice Edge ◽

Airborne Sensors

AbstractSLAR imagery of Nares Strait was obtained on three flights carried out in. January, March, and August of 1973 by Canadian Forces Maritime Proving and Evaluation Unit in an Argus aircraft equipped with a Motorola APS-94D SLAR; the March flight also covered two lines in the Arctic Ocean, from Alert 10 the North Pole and from the Pole down the long. 4ºE. meridian to the ice edge at about lat. 80º N. No observations on the ground were possible, but -some back-up was available on all flights from visual observations recorded in the air, and on the March flight from infrared line-scan and vertical photography.The interpretation of ice features from the SLAR imagery is discussed, and the conclusion reached that in spite of certain ambiguities the technique has great potential which will increase with improving resolution, Extent of coverage per distance flown and independence of light and cloud conditions make it unique among airborne sensors.

Download Full-text

Arctic sea-ice area and volume production:1996/97 versus 1997/98

Annals of Glaciology ◽

10.3189/172756402781817527 ◽

2002 ◽

Vol 34 ◽

pp. 447-453 ◽

Cited By ~ 10

Author(s):

Ron Kwok

Keyword(s):

Arctic Ocean ◽

Large Scale ◽

Heat Budget ◽

Ice Cover ◽

Arctic Sea Ice ◽

The Arctic ◽

Ice Thickness ◽

The Arctic Ocean ◽

Volume Production ◽

Area And Volume

AbstractThe RADARSAT geophysical processor system (RGPS) produces measurements of ice motion and estimates of ice thickness using repeat synthetic aperture radar maps of the Arctic Ocean. From the RGPS products, we compute the net deformation and advection of the winter ice cover using the motion observations, and the seasonal ice area and volume production using the estimates of ice thickness. The results from the winters of 1996/97 and 1997/98 are compared. The second winter is of particular interest because it coincides with the Surface Heat Budget of the Arctic Ocean (SHEBA) field program. The character of the deformation of the ice cover from the two years is very different. Over a domain covering a large part of the western Arctic Ocean (~2.5 × 106 km2), the net divergence of that area during the 6 months of the first winter was 2.7% and for the second winter was 49.3%. In a subregion where the SHEBA camp was located, the net divergence was almost 38% compared to a net divergence of the same subregion of ~9% in 1996/97. The resulting deformation created a much larger volume of seasonal ice than in the earlier year. The net seasonal ice-volume production is 1.6 times (0.38 m vs 0.62 m) that of the first year. In addition to the larger divergence, this part of the ice cover advected a longer distance toward the Chukchi Sea over the same time-span. The total coverage of multi-year ice remained almost identical at ~2.08 × 106 km2, or 83% of the initial area of the domain. In this paper, we compare the behavior of the ice cover over the two winters and discuss these observations in the context of large-scale ice motion and atmospheric-pressure pattern.

Download Full-text