Robert Mossman, Endurance and the Weddell Sea ice

AbstractBorn in Annascaul, Ireland in 1877, Thomas Crean enlisted in the Royal Navy in 1893 and was serving in New Zealand when Scott's British National Antarctic Expedition passed through en route for McMurdo Sound, Antarctica. As an AB in Discovery he gained experience which he later put to good use in two further British expeditions, Scott's British Antarctic (Terra Nova) Expedition, in which he sledged to the polar plateau, and Shackleton's Imperial Tran-Antarctic (Endurance) Expedition, in which he was given charge of the dog teams, drifted on the pack ice of the Weddell Sea and took part in the epic open-boat journey to South Georgia.

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A Discussion on volcanism and the structure of the Earth - The evolution of the Scotia Ridge and Scotia Sea

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1972.0005 ◽

1972 ◽

Vol 271 (1213) ◽

pp. 151-183 ◽

Cited By ~ 72

Keyword(s):

South America ◽

Antarctic Peninsula ◽

Weddell Sea ◽

East Antarctica ◽

The South ◽

Scotia Sea ◽

South Georgia ◽

Scotia Ridge ◽

Magnetic Lineations ◽

The Antarctic

Marine geophysical surveys over the Scotia Ridge show it to be composed of blocks mainly of continental origin. Major structures found on the blocks are in many cases truncated at block margins and their existence is also inconsistent with the present isolated situation of the blocks. The evidence suggests post-Upper Cretaceous fragmentation of a continuous continental area. Complementary marine geomagnetic studies over the deep water of the Scotia Sea have dated two areas as younger than 22 million years (Ma) and have indicated the direction of spreading in others. A model of present plate motions, based on the magnetic anomalies, explains the active volcanism of the South Sandwich Islands as being caused by consumption of Atlantic crust at the associated trench at a rate of 5.5 cm/year for the past 7 to 8 Ma at least. An Upper Tertiary episode of plate consumption at 5 cm/year at the South Shetland trench, suggested by the magnetic lineations, with a secondary slow extensional widening of Bransfield Strait is used to explain similarly the contemporaneous volcanism of the South Shetland Is. Making the reasonable assumption of a Tertiary formation of the undated parts of the Scotia Sea by spreading in the directions indicated by the magnetic lineations, a tentative reconstruction of the component blocks of the Scotia Ridge is made. The attempt is only partly successful in matching structural patterns across adjacent margins of reconstructed blocks, South Georgia being most obviously wrongly situated. It is suggested that the misfits result from minor errors in the initial assumptions and the modification of structures during fragmentation and drift. South Georgia may have formed on the Atlantic rather than the Pacific side of the compact continental region which is thought to have joined South America and west Antarctica for much of the Mesozoic at least. A Gondwanaland reconstruction is presented which is consistent with the Scotia Ridge reconstruction, in which the Antarctic Peninsula lies alongside the Caird Coast of east Antarctica. Upon break-up of Gondwanaland, the Antarctic Peninsula remained rigidly attached to South America, east Antarctica rotating clockwise to open the Weddell Sea, until early Tertiary times when the Peninsula transferred to east Antarctica which continued rotating clockwise to open the Scotia Sea.

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ICESat observations of seasonal and interannual variations of sea-ice freeboard and estimated thickness in the Weddell Sea, Antarctica (2003–2009)

Annals of Glaciology ◽

10.3189/172756411795931480 ◽

2011 ◽

Vol 52 (57) ◽

pp. 43-51 ◽

Cited By ~ 52

Author(s):

Donghui Yi ◽

H. Jay Zwally ◽

John W. Robbins

Keyword(s):

Sea Ice ◽

Weddell Sea ◽

Ice Thickness ◽

Sea Ice Extent ◽

Sea Ice Thickness ◽

Earth Observing System ◽

Pack Ice ◽

Snow Water ◽

The Mean ◽

Seasonal And Interannual Variations

AbstractSea-ice freeboard heights for 17 ICESat campaign periods from 2003 to 2009 are derived from ICESat data. Freeboard is combined with snow depth from Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) data and nominal densities of snow, water and sea ice, to estimate sea-ice thickness. Sea-ice freeboard and thickness distributions show clear seasonal variations that reflect the yearly cycle of growth and decay of the Weddell Sea (Antarctica) pack ice. During October–November, sea ice grows to its seasonal maximum both in area and thickness; the mean freeboards are 0.33–0.41m and the mean thicknesses are 2.10–2.59 m. During February–March, thinner sea ice melts away and the sea-ice pack is mainly distributed in the west Weddell Sea; the mean freeboards are 0.35–0.46m and the mean thicknesses are 1.48–1.94 m. During May–June, the mean freeboards and thicknesses are 0.26–0.29m and 1.32–1.37 m, respectively. the 6 year trends in sea-ice extent and volume are (0.023±0.051)×106 km2 a–1 (0.45% a–1) and (0.007±0.092)×103 km3 a–1 (0.08% a–1); however, the large standard deviations indicate that these positive trends are not statistically significant.

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Albedo of the ice covered Weddell and Bellingshausen Seas

The Cryosphere ◽

10.5194/tc-6-479-2012 ◽

2012 ◽

Vol 6 (2) ◽

pp. 479-491 ◽

Cited By ~ 9

Author(s):

A. I. Weiss ◽

J. C. King ◽

T. A. Lachlan-Cope ◽

R. S. Ladkin

Keyword(s):

Sea Ice ◽

Surface Albedo ◽

Austral Summer ◽

Open Water ◽

Weddell Sea ◽

First Year ◽

Pack Ice ◽

Bellingshausen Sea ◽

The Mean ◽

The Antarctic

Abstract. This study investigates the surface albedo of the sea ice areas adjacent to the Antarctic Peninsula during the austral summer. Aircraft measurements of the surface albedo, which were conducted in the sea ice areas of the Weddell and Bellingshausen Seas show significant differences between these two regions. The averaged surface albedo varied between 0.13 and 0.81. The ice cover of the Bellingshausen Sea consisted mainly of first year ice and the sea surface showed an averaged sea ice albedo of αi = 0.64 ± 0.2 (± standard deviation). The mean sea ice albedo of the pack ice area in the western Weddell Sea was αi = 0.75 ± 0.05. In the southern Weddell Sea, where new, young sea ice prevailed, a mean albedo value of αi = 0.38 ± 0.08 was observed. Relatively warm open water and thin, newly formed ice had the lowest albedo values, whereas relatively cold and snow covered pack ice had the highest albedo values. All sea ice areas consisted of a mixture of a large range of different sea ice types. An investigation of commonly used parameterizations of albedo as a function of surface temperature in the Weddell and Bellingshausen Sea ice areas showed that the albedo parameterizations do not work well for areas with new, young ice.

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The impact of the subtropical South Atlantic SST on South American precipitation

Annales Geophysicae ◽

10.5194/angeo-26-3457-2008 ◽

2008 ◽

Vol 26 (11) ◽

pp. 3457-3476 ◽

Cited By ~ 24

Author(s):

A. S. Taschetto ◽

I. Wainer

Keyword(s):

South America ◽

Southern Oscillation ◽

South Atlantic ◽

Empirical Orthogonal Functions ◽

Convergence Zone ◽

South American ◽

The South ◽

Inter Tropical Convergence Zone ◽

The Impact ◽

Sst Anomalies

Abstract. The Community Climate Model (CCM3) from the National Center for Atmospheric Research (NCAR) is used to investigate the effect of the South Atlantic sea surface temperature (SST) anomalies on interannual to decadal variability of South American precipitation. Two ensembles composed of multidecadal simulations forced with monthly SST data from the Hadley Centre for the period 1949 to 2001 are analysed. A statistical treatment based on signal-to-noise ratio and Empirical Orthogonal Functions (EOF) is applied to the ensembles in order to reduce the internal variability among the integrations. The ensemble treatment shows a spatial and temporal dependence of reproducibility. High degree of reproducibility is found in the tropics while the extratropics is apparently less reproducible. Austral autumn (MAM) and spring (SON) precipitation appears to be more reproducible over the South America-South Atlantic region than the summer (DJF) and winter (JJA) rainfall. While the Inter-tropical Convergence Zone (ITCZ) region is dominated by external variance, the South Atlantic Convergence Zone (SACZ) over South America is predominantly determined by internal variance, which makes it a difficult phenomenon to predict. Alternatively, the SACZ over western South Atlantic appears to be more sensitive to the subtropical SST anomalies than over the continent. An attempt is made to separate the atmospheric response forced by the South Atlantic SST anomalies from that associated with the El Niño – Southern Oscillation (ENSO). Results show that both the South Atlantic and Pacific SSTs modulate the intensity and position of the SACZ during DJF. Particularly, the subtropical South Atlantic SSTs are more important than ENSO in determining the position of the SACZ over the southeast Brazilian coast during DJF. On the other hand, the ENSO signal seems to influence the intensity of the SACZ not only in DJF but especially its oceanic branch during MAM. Both local and remote influences, however, are confounded by the large internal variance in the region. During MAM and JJA, the South Atlantic SST anomalies affect the magnitude and the meridional displacement of the ITCZ. In JJA, the ENSO has relatively little influence on the interannual variability of the simulated rainfall. During SON, however, the ENSO seems to counteract the effect of the subtropical South Atlantic SST variations on convection over South America.

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Atmospheric forcing of coastal polynyas in the south-western Weddell Sea

Antarctic Science ◽

10.1017/s0954102014000893 ◽

2015 ◽

Vol 27 (4) ◽

pp. 388-402 ◽

Cited By ~ 13

Author(s):

Verena Haid ◽

Ralph Timmermann ◽

Lars Ebner ◽

Günther Heinemann

Keyword(s):

Sea Ice ◽

Large Scale ◽

Reanalysis Data ◽

Ocean Model ◽

Weddell Sea ◽

Small Scale ◽

Atmospheric Conditions ◽

Atmospheric Forcing ◽

The South ◽

Ice Production

AbstractThe development of coastal polynyas, areas of enhanced heat flux and sea ice production strongly depend on atmospheric conditions. In Antarctica, measurements are scarce and models are essential for the investigation of polynyas. A robust quantification of polynya exchange processes in simulations relies on a realistic representation of atmospheric conditions in the forcing dataset. The sensitivity of simulated coastal polynyas in the south-western Weddell Sea to the atmospheric forcing is investigated with the Finite-Element Sea ice-Ocean Model (FESOM) using daily NCEP/NCAR reanalysis data (NCEP), 6 hourly Global Model Europe (GME) data and two different hourly datasets from the high-resolution Consortium for Small-Scale Modelling (COSMO) model. Results are compared for April to August in 2007–09. The two coarse-scale datasets often produce the extremes of the data range, while the finer-scale forcings yield results closer to the median. The GME experiment features the strongest winds and, therefore, the greatest polynya activity, especially over the eastern continental shelf. This results in higher volume and export of High Salinity Shelf Water than in the NCEP and COSMO runs. The largest discrepancies between simulations occur for 2008, probably due to differing representations of the ENSO pattern at high southern latitudes. The results suggest that the large-scale wind field is of primary importance for polynya development.

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Sea-Ice Investigations In The Weddell Sea During The German Antarctic Expedition 1979-80

Annals of Glaciology ◽

10.1017/s0260305500005553 ◽

1983 ◽

Vol 4 ◽

pp. 246-252 ◽

Cited By ~ 2

Author(s):

Joachim Schwarz

Keyword(s):

Compressive Strength ◽

Flexural Strength ◽

Sea Ice ◽

Young’S Modulus ◽

Uniaxial Compressive Strength ◽

Young's Modulus ◽

Weddell Sea ◽

Ice Shelves ◽

Antarctic Expedition ◽

Ice Conditions

In the austral winter of 1979-80, a German Antarctic expedition was sent by ship to the Filchner and Ronne ice shelves in order to find a suitable site for the establishment of a permanent Antarctic station. During this expedition, investigations were carried out on sea ice in the Weddell Sea in order to evaluate the accessibility of the site for icebreaking ships which are intended to convey construction materials to the site and, later on, to supply the station annually.This paper covers the results of investigations on sea-ice conditions during the voyage along the ice shelves from Cape Fiske (at the base of the Antarctic Peninsula) to Atka Bay with emphasis on sea-ice conditions in the area about 100 km north-west of Berkner Island (Fig.1.). In addition to the drift conditions (speed, direction), a special feature of multi-year sea ice is described. The main part of the paper deals with mechanical properties such as flexural strength, uniaxial compressive strength and Young’s modulus of columnar-grained sea ice from the southern border of the Weddell Sea. Salinities and temperatures were measured over the depth of the ice and used for calculating the flexural strength and the Young’s modulus of the ice. The uniaxial compressive strength was investigated as a function of strain-rate, brine volume and temperature on a closed-loop testing machine on samples which were carried back from Antarctica to Hamburg.

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Pack-Ice Motion in the Weddell Sea in Relation to Weather Systems and Determination of a Weddell Sea Sea-Ice Budget

Annals of Glaciology ◽

10.1017/s0260305500007047 ◽

1989 ◽

Vol 12 ◽

pp. 104-112 ◽

Cited By ~ 24

Author(s):

D.W.S. Limbert ◽

S.J. Morrison ◽

C.B. Sear ◽

P. Wadhams ◽

M.A. Rowe

Keyword(s):

Sea Ice ◽

Surface Pressure ◽

Ice Cover ◽

Weddell Sea ◽

Air Pressure ◽

Ice Formation ◽

Pack Ice ◽

The Impact

As part of the Winter Weddell Sea Project 1986 (WWSP 86), a buoy, transmitting via TIROS-N satellites to Service Argos, was inserted into an ice floe in the southern Weddell Sea. Operational U.K. Meteorological Office numerical surface-pressure analyses, which utilized the buoy’s measured values of air pressure and temperature, are used to assess the impact of weather systems on pack-ice movement. The motion of the buoy is shown to be related closely to the position of the circumpolar trough and to the tracks of depressions crossing the area. The tracks of this and other buoys deployed during WWSP 86 are analysed, together with the known drifts of some ice-bound vessels, to establish the overall movement of sea ice in the central and western Weddell Sea. Using these data, the area of ice transported northward out of the Weddell Sea is determined. Roughly 60% of the winter sea-ice cover is discharged out of the area, and is replaced by new ice formation in coastal polynyas and by influx of new ice from the east. In summer, a further 30% is discharged northward out of the region, leaving 40% cover and by implication a 30% loss by melting.

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Sea-Ice Investigations In The Weddell Sea During The German Antarctic Expedition 1979-80

Annals of Glaciology ◽

10.3189/s0260305500005553 ◽

1983 ◽

Vol 4 ◽

pp. 246-252

Author(s):

Joachim Schwarz

Keyword(s):

Compressive Strength ◽

Flexural Strength ◽

Sea Ice ◽

Young’S Modulus ◽

Uniaxial Compressive Strength ◽

Young's Modulus ◽

Weddell Sea ◽

Ice Shelves ◽

Antarctic Expedition ◽

Ice Conditions

In the austral winter of 1979-80, a German Antarctic expedition was sent by ship to the Filchner and Ronne ice shelves in order to find a suitable site for the establishment of a permanent Antarctic station. During this expedition, investigations were carried out on sea ice in the Weddell Sea in order to evaluate the accessibility of the site for icebreaking ships which are intended to convey construction materials to the site and, later on, to supply the station annually.This paper covers the results of investigations on sea-ice conditions during the voyage along the ice shelves from Cape Fiske (at the base of the Antarctic Peninsula) to Atka Bay with emphasis on sea-ice conditions in the area about 100 km north-west of Berkner Island (Fig.1.). In addition to the drift conditions (speed, direction), a special feature of multi-year sea ice is described. The main part of the paper deals with mechanical properties such as flexural strength, uniaxial compressive strength and Young’s modulus of columnar-grained sea ice from the southern border of the Weddell Sea. Salinities and temperatures were measured over the depth of the ice and used for calculating the flexural strength and the Young’s modulus of the ice. The uniaxial compressive strength was investigated as a function of strain-rate, brine volume and temperature on a closed-loop testing machine on samples which were carried back from Antarctica to Hamburg.

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Structural characteristics and development of sea ice in the western Ross Sea

Antarctic Science ◽

10.1017/s0954102093000094 ◽

1993 ◽

Vol 5 (1) ◽

pp. 63-75 ◽

Cited By ~ 31

Author(s):

M. O. Jeffries ◽

W. F. Weeks

Keyword(s):

Sea Ice ◽

Internal Structure ◽

Ross Sea ◽

Ice Cores ◽

Arctic Sea Ice ◽

Weddell Sea ◽

The Arctic ◽

Ice Thickness ◽

Pack Ice ◽

Western Ross Sea

The internal structure of ice cores from western Ross Sea pack ice floes showed considerable diversity. Snow-ice formation made a small, but significant contribution to ice growth. Frazil ice was common and its growth clearly occurred during both the pancake cycle and deformation events. Congelation ice was also common, in both its crystallographically aligned and non-aligned varieties. Platelet ice was found in only one core next to the Drygalski Ice Tongue, an observation adding to the increasing evidence that this unusual ice type occurs primarily in coastal pack ice near ice tongues and ice shelves. The diverse internal structure of the floes indicates that sea ice development in the Ross Sea is as complex as that in the Weddell Sea and more complex than in the Arctic. The mean ice thickness at the ice core sites varied between 0.71 m and 1.52 m. The thinnest ice generally occurred in the outer pack ice zone. Regardless of latitude, the ice thickness data are further evidence that Antarctic sea ice is thinner than Arctic sea ice.

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