90° South: Antarctic expedition 1986–87

Polar Record ◽  
1989 ◽  
Vol 25 (152) ◽  
pp. 9-18
Author(s):  
Neil McIntyre

AbstractIn the austral summer 1986–87, the 75th anniversary of Amundsen's conquest of the South Pole, a sledging party of four from a private expedition, 90° South, set out to retrace his route. This was the culmination of five years of preparations, in which sufficient international support was raised to enable the expedition to reach Antarctica and operate independently, using its own ship, MV Aurora… The expedition's Twin Otter aircraft, flying from New Zealand, staged a unique refuelling operation on an iceberg within the pack ice 160 km from the Balleny Islands. Establishing a temporary base at Bay of Whales, Ross Ice Shelf, on 5 December 1986, the expedition used its aircraft to set up supply depots 220 km apart along the route to the pole. The sledging party with two teams of Greenland huskies crossed the ice shelf and ascended the Axel Heiberg Glacier to the polar plateau, reaching their fourth depot in 86°S in late January. Some 400 km short of the Pole, lack of time compelled the party to return to rendezvous with the ship. Glaciological investigations included the formation of icebergs from the Ross Ice Shelf, and collection of ground truth data to help in evaluating remote sensing data. The team also set up a commemorative plaque close to Amundsen' s cairn on Mount Betty.

Author(s):  
K Choudhary ◽  
M S Boori ◽  
A Kupriyanov

The main objective of this study was to detect groundwater availability for agriculture in the Orenburg, Russia. Remote sensing data (RS) and geographic information system (GIS) were used to locate potential zones for groundwater in Orenburg. Diverse maps such as a base map, geomorphological, geological structural, lithology, drainage, slope, land use/cover and groundwater potential zone were prepared using the satellite remote sensing data, ground truth data, and secondary data. ArcGIS software was utilized to manipulate these data sets. The groundwater availability of the study was classified into different classes such as very high, high, moderate, low and very low based on its hydro-geomorphological conditions. The land use/cover map was prepared using a digital classification technique with the limited ground truth for mapping irrigated areas in the Orenburg, Russia.


Polar Record ◽  
2005 ◽  
Vol 41 (4) ◽  
pp. 281-304 ◽  
Author(s):  
William Barr ◽  
James P.C. Watt

On Christmas Eve 1923, the whaling factory ship Sir James Clark Ross, commanded by Captain Carl Anton Larsen and accompanied by five catchers, reached the front of the Ross Ice Shelf; these were the first whaling vessels to operate in the Ross Sea. They had been dispatched by the Norwegian whaling company Hvalfangeraktienselskapet Rosshavet, which had obtained a licence from the British government. For most of the 1923–24 season, Sir James Clark Ross occupied an uneasy anchorage in the deep waters of Discovery Inlet, a narrow embayment in the front of the Ross Ice Shelf, while her catchers pursued whales widely in the Ross Sea. During that first season they killed and processed 221 whales (211 blue whales and 10 fin whales), which yielded 17,300 barrels of oil. During the next decade, with the exception of the 1931–32 season, Sir James Clark Ross and two other factory ships operated by Rosshavet, C.A. Larsen and Sir James Clark Ross II, operated in the Ross Sea. From the 1926–27 season onwards these ships were joined by up to three other factory ships and their catchers, operated by other companies. During the decade 1923–33 the Rosshavet ships killed and processed 9122 whales in the Ross Sea sector, mainly in the open waters of the Ross Sea south of the pack-ice belt. Total harvest for all factory ships from the Ross Sea sector for the period was 18,238 whales (mainly blue whales) producing 1,490,948 barrels of oil. From 1924 onwards the Rosshavet catchers wintered in Paterson Inlet on Stewart Island, New Zealand, and from 1925 onwards a well-equipped shipyard, Kaipipi Shipyard, operated on Price Peninsula in Paterson Inlet to service the Rosshavet ships.


Author(s):  
Richard C. Aster ◽  
Bradley P. Lipovsky ◽  
Hank M. Cole ◽  
Peter D. Bromirski ◽  
Peter Gerstoft ◽  
...  

Abstract Ocean swell interacting with Antarctic ice shelves produces sustained (approximately, 2×106 cycles per year) gravity-elastic perturbations with deformation amplitudes near the ice front as large as tens to hundreds of nanostrain. This process is the most energetically excited during the austral summer, when sea ice-induced swell attenuation is at a minimum. A 2014–2017 deployment of broadband seismographs on the Ross Ice shelf, which included three stations sited, approximately, 2 km from the ice front, reveals prolific swell-associated triggering of discrete near-ice-front (magnitude≲0) seismic subevents, for which we identify three generic types. During some strong swell episodes, subevent timing becomes sufficiently phase-locked with swell excitation, to create prominent harmonic features in spectra calculated across sufficiently lengthy time windows via a Dirac comb effect, for which we articulate a theoretical development for randomized interevent times. These events are observable at near-front stations, have dominant frequency content between 0.5 and 20 Hz, and, in many cases, show highly repetitive waveforms. Matched filtering detection and analysis shows that events occur at a low-background rate during all swell states, but become particularly strongly excited during large amplitude swell at rates of up to many thousands per day. The superimposed elastic energy from swell-triggered sources illuminates the shelf interior as extensional (elastic plate) Lamb waves that are observable more than 100 km from the ice edge. Seismic swarms show threshold excitation and hysteresis with respect to rising and falling swell excitation. This behavior is consistent with repeated seismogenic fracture excitation and growth within a near-ice-front damage zone, encompassing fracture features seen in satellite imagery. A much smaller population of distinctly larger near-front seismic events, previously noted to be weakly associated with extended periods of swell perturbation, likely indicate calving or other larger-scale ice failures near the shelf front.


Polar Record ◽  
2018 ◽  
Vol 54 (2) ◽  
pp. 178-180 ◽  
Author(s):  
Chris S.M. Turney

In ’Why didn't they ask Evans?’ (Turney, 2017), I draw together previously unpublished sources and new analyses of published material to cast further light on the circumstances that led to the fatal events surrounding the return of Captain Robert Falcon Scott's Polar Party on the British Antarctic Expedition (BAE, 1911–1913). Of particular importance are the notes on the meeting between the Royal Geographical Society's President Lord Curzon and the widows Kathleen Scott and Oriana Wilson in April 1913, which explicitly identify Lieutenant Edward ‘Teddy’ Evans as having removed food that exceeded his allocation as a member of the Last Supporting Party (Curzon, 1913), the establishment and almost immediate closure of a ‘Committee of Enquiry’ chaired by Lord Curzon (Beaumont, 1913a, b, c; Cherry-Garrard, 1913a; Darwin, 1913; Goldie, 1913), the recognition of missing food at key depots by the returning Polar Party on the 7, 24 and 27 February 1912 (Scott, 1913a; Wilson, 1912), Evans’ anger at not being selected as a member of the Polar Party and his early departure home (Evans, 1912), the revised timeline of when Evans fell down with scurvy on the Ross Ice Shelf to apparently align with when and where the food was removed (The Advertiser, 3 April 1912, Adelaide: 10) (Cherry-Garrard, 1922; Ellis, 1969; Evans, 1912, 1913a, 1943; Lashly, 1912; Scott, 1913a, 1913b), Evans’ failure to ensure Scott's orders regarding the return of the dog sledging teams had been acted on (Cherry-Garrard, 1922; Gran, 1961; Hattersley-Smith & McGhie, 1984) and the misunderstanding amongst senior Royal Geographical Society members during Evans’ recuperation in the UK that Apsley Cherry-Garrard ‘was to meet the South Pole party, with two teams of dogs, at the foot of the [Beardmore] glacier’ (Markham, 1913). I would like to thank May (2018) for her comment and acknowledge that Edward Wilson's sketchbooks of the expedition's logistics, scientific priorities, sketches and notes on the BAE comprise entries from 1911–1912 and not solely from 1912, which Turney (2017) used to denote the year of the last entry.


2020 ◽  
Vol 66 (259) ◽  
pp. 861-875
Author(s):  
Emilie Klein ◽  
Cyrille Mosbeux ◽  
Peter D. Bromirski ◽  
Laurie Padman ◽  
Yehuda Bock ◽  
...  

AbstractIce shelves play a critical role in modulating dynamic loss of ice from the grounded portion of the Antarctic Ice Sheet and its contribution to sea-level rise. Measurements of ice-shelf motion provide insights into processes modifying buttressing. Here we investigate the effect of seasonal variability of basal melting on ice flow of Ross Ice Shelf. Velocities were measured from November 2015 to December 2016 at 12 GPS stations deployed from the ice front to 430 km upstream. The flow-parallel velocity anomaly at each station, relative to the annual mean, was small during early austral summer (November–January), negative during February–April, and positive during austral winter (May–September). The maximum velocity anomaly reached several metres per year at most stations. We used a 2-D ice-sheet model of the RIS and its grounded tributaries to explore the seasonal response of the ice sheet to time-varying basal melt rates. We find that melt-rate response to changes in summer upper-ocean heating near the ice front will affect the future flow of RIS and its tributary glaciers. However, modelled seasonal flow variations from increased summer basal melting near the ice front are much smaller than observed, suggesting that other as-yet-unidentified seasonal processes are currently dominant.


1975 ◽  
Vol 15 (73) ◽  
pp. 457-458 ◽  
Author(s):  
John W. Clough

Bottom crevasses were detected at many locations in the southern portion of the Ross Ice Shelf during the 1973-74 austral summer. The crevasses which extended up about 100 m from the bottom of the shelf were detected by radio-echo sounding. These linear features were mapped in some detail at the RISP Camp. Wide-angle reflection velocity measurements, airborne radio-echo sounding, and other results of the R1GGS program will be included in the discussion.


Author(s):  
T. Altanchimeg ◽  
T. Renchin ◽  
P. De Maeyer ◽  
E. Natsagdorj ◽  
B. Tseveen ◽  
...  

Abstract. The forest biomass is one of the most important parameters for the global carbon stock. Information on the forest volume, coverage and biomass are important to develop the global perspective on the CO2 concentration changes. Objective of this research is to estimate forest biomass in the study area. The study area is Hangal sum, Bulgan province, Mongolia. Backscatter coefficients for vertical transmit and vertical receive (VV), for vertical transmit and horizontal receive (VH) from Sentinel data and Leaf Area Index (LAI) from Landsat data were used in the study area. We developed biomass estimation approach using ground truth data which is DBH, height and soil moisture. The coefficient α, β, δ, γ were found from the approach. The output map from the approach was compared with VV and VH, LAI data. The relationship between output map and VH data shows a positive result R2 = 0.61. This study suggests that the biomass estimation using Remote sensing data can be applied in forest region in the North.


Geophysics ◽  
1992 ◽  
Vol 57 (10) ◽  
pp. 1359-1372 ◽  
Author(s):  
Bruce C. Beaudoin ◽  
Uri S. ten Brink ◽  
Tim A. Stern

Coincident reflection and refraction data, collected in the austral summer of 1988/89 by Stanford University and the Geophysical Division of the Department of Scientific and Industrial Research, New Zealand, imaged the crust beneath the Ross Ice Shelf, Antarctica. The Ross Ice Shelf is a unique acquisition environment for seismic reflection profiling because of its thick, floating ice cover. The ice shelf velocity structure is multilayered with a high velocity‐gradient firn layer constituting the upper 50 to 100 m. This near surface firn layer influences the data character by amplifying and frequency modulating the incoming wavefield. In addition, the ice‐water column introduces pervasive, high energy seafloor, intra‐ice, and intra‐water multiples that have moveout velocities similar to the expected subseafloor primary velocities. Successful removal of these high energy multiples relies on predictive deconvolution, inverse velocity stack filtering, and frequency filtering. Removal of the multiples reveals a faulted, sedimentary wedge which is truncated at or near the seafloor. Beneath this wedge the reflection character is diffractive to a two‐way traveltime of ∼7.2 s. At this time, a prominent reflection is evident on the southeast end of the reflection profile. This reflection is interpreted as Moho indicating that the crust is ∼21-km thick beneath the profile. These results provide seismic evidence that the extensional features observed in the Ross Sea region of the Ross Embayment extend beneath the Ross Ice Shelf.


Author(s):  
S. Kumar ◽  
S. Saxena ◽  
S. K. Dubey ◽  
K. Chaudhary ◽  
S. Sehgal ◽  
...  

<p><strong>Abstract.</strong> Wheat (<i>Triticum aestivum</i> L.) is a major cereal crop of the world, which plays an important role in global food and nutritional security. In India, wheat grown areas are more as compared to other food crops, except for rice. The total area under wheat cultivation is 30.60 million hectares with production of 98.38 million tonnes and the productivity is 3.22 tonnes /hectare (DES, 2017). The main objective of this paper is to highlight the development of satellite-based methodology, compare the relative deviations (%) at national level, RMSE (%) and correlation coefficient at state level and correlation coefficient at district level between DES and FASAL estimates from 2013 to 2017. It was observed that the area and production estimates improved with improvement in the satellite resolution and ground truth data. During the last 10 years of estimation the spatial resolution of the satellite data has gradually improved from 23.5 meter of (Reourcesat-2, LISS-III) and finally 10&amp;thinsp;m of Sentinel-2, MSI, which is being currently used for acreage estimation purpose. Hooda R.S et al (2006) studied that the improvement in the spatial resolution, spectral and temporal resolution of the satellite data has also improved the crop discrimination. Both accuracy as well as precision of the estimates has improved over the years from 2013 to 2017, as reflected by relative deviation, RMSE (%) and Coefficient of correlation values at national, state and district level respectively.</p>


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