Structure, Salinity and Density of Multi-Year Sea Ice Pressure Ridges

1985 ◽  
Vol 107 (4) ◽  
pp. 493-497 ◽  
Author(s):  
J. A. Richter-Menge ◽  
G. F. N. Cox
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Beaufort Sea ◽  
Pressure Ridge ◽  
Sample Data ◽  
Ice Loads ◽  
Scale Properties ◽  
Ice Pressure

Data are presented on the variation of ice structure, salinity, and density in multi-year pressure ridges from the Beaufort Sea. Two continuous multi-year pressure ridge cores are examined as well as ice sample data from numerous other pressure ridges. The results suggest that the large scale properties of multi-year pressure ridges are not isotropic, and that the use of anisotropic ridge models may result in lower design ridge ice loads.

scholarly journals Toward a method for downscaling sea ice pressure

2020 ◽  
Author(s):  
Jean-Francois Lemieux ◽  
Bruno Tremblay ◽  
Mathieu Plante
Keyword(s):  
High Pressure ◽  
Sea Ice ◽  
Numerical Experiments ◽  
Large Scale ◽  
High Stress ◽  
Small Scale ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
High Stress Concentration ◽  
Ice Pressure

Abstract. Sea ice pressure poses great risk for navigation; it can lead to ship besetting and damages. Contemporary large-scale sea ice forecasting systems can predict the evolution of sea ice pressure. There is, however, a mismatch between the spatial resolution of these systems (a few km) and the typical dimensions of ships (a few tens of m) navigating in ice-covered regions. In this paper, we investigate the downscaling of sea ice pressure from the km-scale to scales relevant for ships. Results show that sub-grid scale pressure values can be significantly larger than the large-scale pressure (up to $\\sim$ 4x larger in our numerical experiments). High pressure at the sub-grid scale is associated with the presence of defects (e.g. a lead). Numerical experiments show that a ship creates its own high stress concentration by forming a lead in its wake while navigating. These results also highlight the difficulty of forecasting the small-scale distribution of pressure and especially the largest values. Indeed, this distribution strongly depends on variables that are not well constrained: the rheology parameters and the small-scale structure of sea ice thickness (more importantly the length of the lead behind the ship).

Source level measurements of an arctic sea ice pressure ridge

1979 ◽  
Vol 66 (S1) ◽  
pp. S25-S26 ◽  
Author(s):  
Beaumont M. Buck ◽  
Charles R. Greene
Keyword(s):  
Sea Ice ◽  
Arctic Sea Ice ◽  
Pressure Ridge ◽  
Arctic Sea ◽  
Source Level ◽  
Ice Pressure

scholarly journals Variability and changes of Arctic sea ice thickness distribution under different AO/DA states

2011 ◽  
Vol 5 (1) ◽  
pp. 131-167
Author(s):  
A. Oikkonen ◽  
J. Haapala
Keyword(s):  
Sea Ice ◽  
Seasonal Variability ◽  
Large Scale ◽  
Thickness Distribution ◽  
Beaufort Sea ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Ice Pack

Abstract. Changes of the mean sea ice thickness and concentration in the Arctic are well known. However, comparable little is known about the ice thickness distribution and the composition of ice pack in quantity. In this paper we determine the ice thickness distributions, mean and modal thicknesses, and their regional and seasonal variability in the Arctic under different large scale atmospheric circulation modes. We compare characteristics of the Arctic ice pack during the periods 1975–1987 and 1988–2000, which have a different distribution in the AO/DA space. The study is based on submarine measurements of sea ice draft. The prevalent feature is that the peak of sea ice thickness distributions has generally taken a narrower form and shifted toward thinner ice. Also, both mean and modal ice thickness have generally decreased. These noticeable changes result from a loss of thick, mostly deformed, ice. In the spring the loss of the volume of ice thicker than 5 m exceeds 35% in all regions except the Nansen Basin, and the reduction is as much as over 45% at the North Pole and in the Eastern Arctic. In the autumn the volume of thick, mostly deformed ice has decreased by more than 40% in the Canada Basin only, but the reduction is more than 30% also in the Beaufort Sea and in the Chukchi Sea. In the Beaufort Sea region the decrease of the modal draft has been so strong that the peak has shifted from multiyear ice to first-year type ice. Also, the regional and seasonal variability of the sea ice thickness has decreased, since the thinning has been the most pronounced in the regions with the thickest pack ice (the Western Arctic), and during the spring (0.6–0.8 m per decade).

scholarly journals An Edge-Referenced Surface Fresh Layer in the Beaufort Sea Seasonal Ice Zone

2017 ◽  
Vol 47 (5) ◽  
pp. 1125-1144 ◽  
Author(s):  
Sarah R. Dewey ◽  
James H. Morison ◽  
Jinlun Zhang
Keyword(s):  
Sea Ice ◽  
Large Scale ◽  
Vertical Mixing ◽  
Heat Content ◽  
Beaufort Sea ◽  
Coast Guard ◽  
Ice Melt ◽  
Ice Edge ◽  
Gyre Circulation ◽  
Seasonal Ice Zone

AbstractTo understand the factors causing the interannual variations in the summer retreat of the Beaufort Sea ice edge, Seasonal Ice Zone Reconnaissance Surveys (SIZRS) aboard U.S. Coast Guard Arctic Domain Awareness flights were made monthly from June to October in 2012, 2013, and 2014. The seasonal ice zone (SIZ) is where sea ice melts and reforms annually and encompasses the nominally narrower marginal ice zone (MIZ) where a mix of open-ocean and ice pack processes prevail. Thus, SIZRS provides a regional context for the smaller-scale MIZ processes. Observations with aircraft expendable conductivity–temperature–depth probes reveal a salinity pattern associated with large-scale gyre circulation and the seasonal formation of a shallow (~20 m) fresh layer moving with the ice edge position. Repeat occupations of the SIZRS lines from 72° to 76°N on 140° and 150°W allow a comparison of observed hydrography to atmospheric indices. Using this relationship, the basinwide salinity signals are separated from the fresh layer associated with the ice edge. While this layer extends northward under the ice edge as the melt season progresses, low salinities and warm temperatures appear south of the edge. Within this fresh layer, average salinity is correlated with distance from the ice edge. The salinity observations suggest that the upper-ocean freshening over the summer is dominated by local sea ice melt and vertical mixing. A Price–Weller–Pinkel model analysis reveals that observed changes in heat content and density structure are also consistent with a 1D mixing process.

scholarly journals Late Winter Observations of Sea Ice Pressure Ridge Sail Height

2020 ◽  
pp. 1-5
Author(s):  
Kyle Duncan ◽  
Sinead L. Farrell ◽  
Jennifer Hutchings ◽  
Jacqueline Richter-Menge
Keyword(s):  
Sea Ice ◽  
Late Winter ◽  
Pressure Ridge ◽  
Ice Pressure

scholarly journals Arctic sea-ice melt in 2008 and the role of solar heating

2011 ◽  
Vol 52 (57) ◽  
pp. 355-359 ◽  
Author(s):  
Donald K. Perovich ◽  
Jacqueline A. Richter-Menge ◽  
Kathleen F. Jones ◽  
Bonnie Light ◽  
Bruce C. Elder ◽  
...  
Keyword(s):  
Sea Ice ◽  
Heat Input ◽  
Large Scale ◽  
Beaufort Sea ◽  
Arctic Sea Ice ◽  
Solar Heat ◽  
Ice Melt ◽  
Ice Surface ◽  
Arctic Sea ◽  
Ice Concentration

AbstractThere has been a marked decline in the summer extent of Arctic sea ice over the past few decades. Data from autonomous ice mass-balance buoys can enhance our understanding of this decline. These buoys monitor changes in snow deposition and ablation, ice growth, and ice surface and bottom melt. Results from the summer of 2008 showed considerable large-scale spatial variability in the amount of surface and bottom melt. Small amounts of melting were observed north of Greenland, while melting in the southern Beaufort Sea was quite large. Comparison of net solar heat input to the ice and heat required for surface ablation showed only modest correlation. However, there was a strong correlation between solar heat input to the ocean and bottom melting. As the ice concentration in the Beaufort Sea region decreased, there was an increase in solar heat to the ocean and an increase in bottom melting.

scholarly journals High-resolution airborne observations of sea-ice pressure ridge sail height

2018 ◽  
Vol 59 (76pt2) ◽  
pp. 137-147 ◽  
Author(s):  
K. Duncan ◽  
S. L. Farrell ◽  
L. N. Connor ◽  
J. Richter-Menge ◽  
J. K. Hutchings ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
The Arctic ◽  
Height Distribution ◽  
Ice Dynamics ◽  
Sea Ice Dynamics ◽  
Pressure Ridge ◽  
High Resolution Models ◽  
Energy And Momentum ◽  
Ice Pressure

ABSTRACTPressure ridges impact the mass, energy and momentum budgets of the sea-ice cover and present an obstacle to transportation through ice-infested waters. Quantifying ridge characteristics is important for understanding total sea-ice mass and for improving the representation of sea-ice dynamics in high-resolution models. Multi-sensor measurements collected during annual Operation IceBridge (OIB) airborne surveys of the Arctic provide new opportunities to assess the sea ice at the end of winter. We present a new methodology to derive ridge sail height from high-resolution OIB Digital Mapping System (DMS) visible imagery. We assess the efficacy of the methodology by mapping the full sail height distribution along 12 pressure ridges in the western and central Arctic. Comparisons against coincident Airborne Topographic Mapper (ATM) elevation anomalies are used to demonstrate the methodology and evaluate DMS-derived sail heights. Sail heights and elevation anomalies were correlated at 0.81 or above. On average mean and maximum sail height agreed with ATM elevation to within 0.11 and 0.49 m, respectively. Of the ridges mapped, mean sail height ranged from 0.99 to 2.16 m, while maximum sail height ranged from 2.1 to 4.8 m. DMS also delivered higher sampling along ridge crests than coincident ATM data.

scholarly journals Late Winter Observations of Sea Ice Pressure Ridge Sail Heights

2019 ◽  
Author(s):  
Kyle Duncan ◽  
Sinéad Farrell ◽  
Jennifer Hutchings ◽  
RoseAnne Dominguez ◽  
Jacqueline Richter-Menge ◽  
...  
Keyword(s):  
Sea Ice ◽  
Late Winter ◽  
Pressure Ridge ◽  
Ice Pressure
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