Thickness and surface‐properties of different sea‐ice regimes within the Arctic Trans Polar Drift: Data from summers 2001, 2004 and 2007

Abstract

[1] Large-scale sea-ice thickness and surface property data were obtained in three summers and in three different sea-ice regimes in the Arctic Trans-Polar Drift (TPD) by means of helicopter electromagnetic sounding. Distribution functions P of sea-ice thickness and of the height, spacing, and density of sails were analyzed to characterize ice regimes of different ages and deformations. Results suggest that modal ice thickness is affected by the age of a sea-ice regime and that the degree of deformation is represented by the shape of P. Mean thickness changes with both age and deformation. Standard error calculations showed that representative mean and modal thickness could be obtained with transect lengths of 15 km and 50 km, respectively, in less deformed ice regimes such as those around the North Pole. In heavier deformed ice regimes closer to Greenland, 100 km transects were necessary for mean thickness determination and a representative modal thickness could not be obtained at all. Mean sail height did not differ between ice regimes, whereas sail density increased with the degree of deformation.

Characterizing Arctic sea ice topography using high-resolution IceBridge data

“…An ordinary exponential distribution of sail heights was proposed by Wadhams (1980), which has been validated (to varying degrees) by further observations of sail/feature height (e.g. Tucker et al, 1979;Dierking, 1995;Martin, 2007;Rabenstein et al, 2010;Tan et al, 2012). As discussed earlier (Sect.…”

“…those resolving distinct pressure ridges at the metre scale) have been based predominantly on airborne and underwater measurements (e.g. Tucker et al, 1979;Wadhams, 1980Wadhams, , 1981Tucker et al, 1984;Wadhams and Davy, 1986;Haas, 2004;Martin, 2007;Rabenstein et al, 2010). More recently, Doble et al (2011) used coincident autonomous underwater vehicle (AUV) sonar and airborne laser profiling to perform a high-resolution, three-dimensional analysis of sea ice morphology; however this was limited to one region within the Beaufort Sea.…”

Summer sea ice characteristics and morphology in the Pacific Arctic sector as observed during the CHINARE 2010 cruise

“…In 2005, no snow was found on sea ice up to 84.3 • N (29 August 2005) and about ∼ 10 cm thereafter; in 2010, besides a similar decomposed granular sea ice layer (less than 10 cm) seen throughout the ice zone, several snowfall events (since 31 July) added ∼ 8 cm new snow on top of the decomposed granular sea ice layer seen from 78-87.5 • N; the new snow was then melted away due to a rainfall event on 17 August. In the North Pole region, during the helicopter-based electromagnetic measurements of 2001, 2004, and 2007, no snow cover was observed in August and 10 cm new snow seen in September (Haas et al, 2008;Rabenstein et al, 2010). The ice thinning in 2010 as compared with 2005 provides additional information to support the significant ice thinning from the submarine period (1958)(1959)(1960)(1961)(1962)(1963)(1964)(1965)(1966)(1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976) to ICESat period (2003ICESat period ( -2008 (Kwok, 2011;Kwok and Untersteiner, 2011) for the Pacific Arctic Sector and air-borne EM31 based ice thickness measurements from 2001 to 2009 for the Central Arctic (Haas et al, 2008.…”

A combined approach of remote sensing and airborne electromagnetics to determine the volume of polynya sea ice in the Laptev Sea

“…They were first applied on the ice surface by Sinha (1976) and from a helicopter by Kovacs and Holladay (1990). Since then, a variety of sea-ice thickness studies have incorporated the results of airborne EM surveys (e.g., Multala et al, 1996;Prinsenberg et al, 2002;Rabenstein et al, 2010). For our study, the helicopter EM-Bird from the Alfred Wegener Institute (AWI) was employed (Haas et al, 2009) and the helicopter used was a Russian Mi-8.…”

“…6 and 7. We applied the level ice filter of Rabenstein et al (2010) to all thickness data in order to isolate sections of undeformed ice (i.e., sea ice formed from simple freezing processes). This filter identified > 100 m lengths of level ice over which the average thickness change per length was below 0.04 m per 4 m, which was one sample interval.…”