scholarly journals A Survey of the Vanderford and Adams Glaciers in East Antarctica (Abstract)

1986 ◽  
Vol 8 ◽  
pp. 197
Author(s):  
E R. Davis ◽  
D.J. Jones ◽  
V.I. Morgan ◽  
N.W. Young
Keyword(s):  
Austral Summer ◽  
Ice Thickness ◽  
The South ◽  
Data Logger ◽  
Gravity Measurements ◽  
Elevation Data ◽  
Glacier Flow ◽  
To Come ◽  
Navigation Equipment ◽  
Ice Radar

A comprehensive, airborne survey of the Vanderford and Adams glaciers was started in January 1983, continued through the austral summer season 1984/5, and completed in February 1985. Ice-thickness and surface-elevation data were collected over some 4500 square kilometres, on a grid spacing of approximately 5 kilometres. The measurement system was based on a Bell 206 helicopter, fitted with ANARE 100 MHz ice radar, Motorola Mini-Ranger navigation equipment, and a digital, pressure altimeter. A JMR, satellite, doppler receiver was used to position the navigation ground stations precisely. Gravity measurements were used to fill in ice-thickness coverage, where the ice radar failed to produce an echo and also to help determine where the glacier was floating. Ice-movement profiles were measured across the front sections of the glaciers and additional spot values were obtained further upstream by utilizing the 3 m accuracy of the navigation equipment to locate markers quickly at both the beginning and end of the season’s work. A data logger in the helicopter recorded time, navigation distances, aircraft to ground clearance, and air pressure, at 10 second intervals. These data were later merged with manually-scaled, ice-thickness values, for computer processing. The results show that the Vanderford glacier dominates the system and drains about 5 cubic kilometres of ice per annum, mainly from the inland ice sheet to the south. Ice flowing into the Adams Glacier tends to come from nearer the coast and to the south and west of the glacier. Bedrock topography beneath the Vanderford shows that the deep, inland trench, similar to that found below other outlet glaciers, drops to 2500 m below sea level, 60 kilometres from the front. The trench has steep sides to the east and gives a clearly-defined edge to the fast glacier flow. The western side, however, is much more complicated, particularly further inland, where the flow is not clearly separate from that of the Adams glacier.

scholarly journals A Survey of the Vanderford and Adams Glaciers in East Antarctica (Abstract)

1986 ◽  
Vol 8 ◽  
pp. 197-197 ◽  
Author(s):  
E R. Davis ◽  
D.J. Jones ◽  
V.I. Morgan ◽  
N.W. Young
Keyword(s):  
Austral Summer ◽  
Ice Thickness ◽  
The South ◽  
Data Logger ◽  
Gravity Measurements ◽  
Elevation Data ◽  
Glacier Flow ◽  
To Come ◽  
Navigation Equipment ◽  
Ice Radar

A comprehensive, airborne survey of the Vanderford and Adams glaciers was started in January 1983, continued through the austral summer season 1984/5, and completed in February 1985.Ice-thickness and surface-elevation data were collected over some 4500 square kilometres, on a grid spacing of approximately 5 kilometres.The measurement system was based on a Bell 206 helicopter, fitted with ANARE 100 MHz ice radar, Motorola Mini-Ranger navigation equipment, and a digital, pressure altimeter. A JMR, satellite, doppler receiver was used to position the navigation ground stations precisely. Gravity measurements were used to fill in ice-thickness coverage, where the ice radar failed to produce an echo and also to help determine where the glacier was floating.Ice-movement profiles were measured across the front sections of the glaciers and additional spot values were obtained further upstream by utilizing the 3 m accuracy of the navigation equipment to locate markers quickly at both the beginning and end of the season’s work.A data logger in the helicopter recorded time, navigation distances, aircraft to ground clearance, and air pressure, at 10 second intervals. These data were later merged with manually-scaled, ice-thickness values, for computer processing.The results show that the Vanderford glacier dominates the system and drains about 5 cubic kilometres of ice per annum, mainly from the inland ice sheet to the south. Ice flowing into the Adams Glacier tends to come from nearer the coast and to the south and west of the glacier. Bedrock topography beneath the Vanderford shows that the deep, inland trench, similar to that found below other outlet glaciers, drops to 2500 m below sea level, 60 kilometres from the front. The trench has steep sides to the east and gives a clearly-defined edge to the fast glacier flow. The western side, however, is much more complicated, particularly further inland, where the flow is not clearly separate from that of the Adams glacier.

scholarly journals Determination of the Surface and Bed Topography in Central Greenland

1990 ◽  
Vol 36 (122) ◽  
pp. 17-30 ◽  
Author(s):  
Steven M. Hodge ◽  
David L. Wright ◽  
Jerry A. Bradley ◽  
Robert W. Jacobel ◽  
Neils Skou ◽  
...  
Keyword(s):  
Surface Topography ◽  
Sea Level ◽  
Bottom Topography ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Thickness ◽  
Radar Altimeter ◽  
The South ◽  
South West ◽  
Ice Radar

AbstractThe surface and bottom topography of the central Greenland ice sheet was determined from airborne ice-radar soundings over a 180 km by 180 km grid centered on the 1974 “Summit” site (lat. 72°18′N., long. 37°55′W.), using the Technical University of Denmark 60 MHz ice radar. Over 6100 km of high-quality radar data were obtained, covering over 99'% of the grid, along lines spaced 12.5 km apart in both north-south and east-west directions. Aircraft location was done with an inertial navigation system (INS) and a pressure altimeter, with control provided by periodically flying over a known point at the center of the grid. The ice radar was used to determine ice thickness; the surface topography was determined independently using height-above-terrain measurements from the aircraft’s radar altimeter. The calculated surface topography is accurate to about ±6 m, with this error arising mostly from radar-altimeter errors. The ice thickness and bottom topography are accurate to about ±50 m, with this error dominated by the horizontal navigation uncertainties due to INS drift; this error increases to about ±125 m in areas of rough bottom relief (about 12% of the grid).The highest point on Greenland is at lat. 72°34′ N., long. 37°38′W., at an altitude of 3233 ± 6 m a.s.l. The ice surface at this point divides into three sectors, one facing north, one east-south-east, and one west-south-west, with each having a roughly uniform slope. The ice divide between the last two sectors is a well-defined ridge running almost due south. The ice is about 3025 m thick at the summit. Excluding the mountainous north-east corner of the grid, where the ice locally reaches a thickness of about 3470 m and the bed dips to about 370 m below sea-level, the maximum ice thickness, approximately 3375 m, occurs about 97 km south-south-west of the summit. The average bed altitude over the entire grid is 180 m and the average ice thickness is 2975 ± 235 m. The ice in most of the south-west quadrant of the grid is over 3200 m thick, and overlies a relatively smooth, flat basin with altitudes mostly below sea-level. There is no predominant direction to the basal topography over most of the grid; it appears to be undulating, rolling terrain with no obvious ridge/valley structure. The summit of the ice sheet is above the eastern end of a relatively large, smooth, flat plateau, about 10–15 km wide and extending about 50 km to the west. If the basal topography were the sole criterion, then a site somewhere on this plateau or in the south-west basin would be suitable for the drilling of a new deep ice core.

Determination of the Surface and Bed Topography in Central Greenland

1990 ◽  
Vol 36 (122) ◽  
pp. 17-30 ◽  
Author(s):  
Steven M. Hodge ◽  
David L. Wright ◽  
Jerry A. Bradley ◽  
Robert W. Jacobel ◽  
Neils Skou ◽  
...  
Keyword(s):  
Surface Topography ◽  
Sea Level ◽  
Bottom Topography ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Ice Thickness ◽  
Radar Altimeter ◽  
The South ◽  
South West ◽  
Ice Radar

AbstractThe surface and bottom topography of the central Greenland ice sheet was determined from airborne ice-radar soundings over a 180 km by 180 km grid centered on the 1974 “Summit” site (lat. 72°18′N., long. 37°55′W.), using the Technical University of Denmark 60 MHz ice radar. Over 6100 km of high-quality radar data were obtained, covering over 99'% of the grid, along lines spaced 12.5 km apart in both north-south and east-west directions. Aircraft location was done with an inertial navigation system (INS) and a pressure altimeter, with control provided by periodically flying over a known point at the center of the grid. The ice radar was used to determine ice thickness; the surface topography was determined independently using height-above-terrain measurements from the aircraft’s radar altimeter. The calculated surface topography is accurate to about ±6 m, with this error arising mostly from radar-altimeter errors. The ice thickness and bottom topography are accurate to about ±50 m, with this error dominated by the horizontal navigation uncertainties due to INS drift; this error increases to about ±125 m in areas of rough bottom relief (about 12% of the grid).The highest point on Greenland is at lat. 72°34′ N., long. 37°38′W., at an altitude of 3233 ± 6 m a.s.l. The ice surface at this point divides into three sectors, one facing north, one east-south-east, and one west-south-west, with each having a roughly uniform slope. The ice divide between the last two sectors is a well-defined ridge running almost due south. The ice is about 3025 m thick at the summit. Excluding the mountainous north-east corner of the grid, where the ice locally reaches a thickness of about 3470 m and the bed dips to about 370 m below sea-level, the maximum ice thickness, approximately 3375 m, occurs about 97 km south-south-west of the summit. The average bed altitude over the entire grid is 180 m and the average ice thickness is 2975 ± 235 m. The ice in most of the south-west quadrant of the grid is over 3200 m thick, and overlies a relatively smooth, flat basin with altitudes mostly below sea-level. There is no predominant direction to the basal topography over most of the grid; it appears to be undulating, rolling terrain with no obvious ridge/valley structure. The summit of the ice sheet is above the eastern end of a relatively large, smooth, flat plateau, about 10–15 km wide and extending about 50 km to the west. If the basal topography were the sole criterion, then a site somewhere on this plateau or in the south-west basin would be suitable for the drilling of a new deep ice core.

SEISMIC AND GRAVITY STUDIES AT THE SOUTH POLE

Geophysics ◽  
1963 ◽  
Vol 28 (4) ◽  
pp. 582-592 ◽  
Author(s):  
John G. Weihaupt
Keyword(s):  
Density Profile ◽  
Seismic Reflection ◽  
Gravity Data ◽  
Austral Summer ◽  
Maximum Velocity ◽  
Ice Thickness ◽  
South Pole ◽  
The South ◽  
Compressional Waves

Results of a seismic and gravity study at the South Pole during the 1961–62 austral summer are presented. Seismic compressional waves in the ice at the South Pole are shown to reach a maximum velocity of 3,925 m/sec at a depth of 186 m. This depth is attributed to the density profile of the ice. An ice thickness of 2,900 m is indicated from seismic reflection shooting. Gravity data reveal flat topography underlying the ice in the vicinity of the South Pole.

scholarly journals Changing brown cities to smart and sustainable ones: Proposed applicable strategies and indicators for Omid-e-Sabz township in Kabul city

2021 ◽  
Vol 4 (2) ◽  
pp. 62-72
Author(s):  
Abdullah Tajzai ◽  
Najib Rahman Sabory
Keyword(s):  
Climate Change ◽  
Urban Planning ◽  
Population Growth ◽  
Urban Development ◽  
Smart City ◽  
World Wide ◽  
The South ◽  
New Approaches ◽  
South West ◽  
To Come

The two world-wide challenges, the population growth and the climate change, have forced everyone to think differently and seek new approaches to revive cities to be sustainable for centuries to come. Therefore, transforming the cities to the green and smart city are inevitable. The first step towards green and smart city is the recognition of applicable indicators for an existing city. In the next stage, introducing the most sustainable strategies to implement and realize the introduced indicators are of key importance. Omid-e-Sabz is a crowded city in the south-west of Kabul, hosts more than 27,000 inhabitants. Thus, a study through modifying this city to a sustainable and smart city is crucial for future urban development in Afghanistan. The indicators of green and smart city have been analyzed for Omid-e-Sabz Town in this paper. Moreover, some key guidance’s and plans for transforming an ordinary city to sustainable and smart city have been introduced and suggested. This paper is the first of its kind that discusses this important topic for Afghanistan. It will help the urban planning sector of Afghanistan to learn and continue this discourse to make sure the future cities in Afghanistan are smart and sustainable.

scholarly journals A unifying framework for iceberg-calving models

2010 ◽  
Vol 56 (199) ◽  
pp. 822-830 ◽  
Author(s):  
Jason M. Amundson ◽  
Martin Truffer
Keyword(s):  
Empirical Relationship ◽  
Ice Thickness ◽  
Ice Shelf ◽  
Physical Explanation ◽  
Positive Feedbacks ◽  
First Order ◽  
External Forcings ◽  
Iceberg Calving ◽  
Calving Rate ◽  
Glacier Flow

AbstractWe propose a general framework for iceberg-calving models that can be applied to any calving margin. The framework is based on mass continuity, the assumption that calving rate and terminus velocity are not independent and the simple idea that terminus thickness following a calving event is larger than terminus thickness at the event onset. The theoretical, near steady-state analysis used to support and analyze the framework indicates that calving rate is governed, to first order, by ice thickness, thickness gradient, strain rate, mass-balance rate and backwards melting of the terminus; the analysis furthermore provides a physical explanation for a previously derived empirical relationship for ice-shelf calving (Alley and others, 2008). In the calving framework the pre- and post-calving terminus thicknesses are given by two unknown but related functions. The functions can vary independently of changes in glacier flow and geometry, and can therefore account for variations in calving behavior due to external forcings and/or self-sustaining calving processes (positive feedbacks). Although the calving framework does not constitute a complete calving model, any thickness-based calving criterion can easily be incorporated into the framework. The framework should be viewed as a guide for future attempts to parameterize calving.

Swell Genesis, Modelling and Measurements in West Africa

2013 ◽  
Author(s):  
Marc Prevosto ◽  
Kevin Ewans ◽  
George Z. Forristall ◽  
Michel Olagnon
Keyword(s):  
West Africa ◽  
Numerical Models ◽  
Austral Summer ◽  
In Situ Measurements ◽  
West African ◽  
The South ◽  
West African Coast ◽  
Westerly Direction ◽  
Propagation Of Waves

Swell events show a large variety of configurations when they arrive at sites off West Africa after generation and propagation of waves across the Atlantic Ocean. Within the West Africa Swell Project (WASP JIP), these different configurations have been described and discussed and the ability of numerical models to reproduce faithfully their properties has been assessed from comparisons with in-situ measurements. During the austral winter months, swells approach West African coast from the south to south-westerly direction. These swells are generated by storms in the South Atlantic mainly between 40°S and 60°S. But during austral summer, north-westerly swells are also observed coming from North Atlantic. Typical situations of superposition of these different swells are illustrated in the paper. In spite of a poor overlapping between numerical and in-situ measurements databases at the time of the WASP project, and of reduced durations of measurement campaigns, comparisons between in situ measurements and hindcast models permitted identification of the limitations of the different numerical models available. Three sites have been used for this study, one in the Gulf of Guinea with directional Waverider and Wavescan buoys, a second one off Namibia with a directional Waverider and one last instrumented with two wavestaffs off Cabinda (Angola). In addition, the existence of infra-gravity waves in shallow water measurements has been investigated.

The Tejon Pass earthquake of October 22, 1916

1917 ◽  
Vol 7 (2) ◽  
pp. 51-60
Author(s):  
John Casper Branner
Keyword(s):  
Los Angeles ◽  
San Francisco ◽  
Fault Zone ◽  
Fault Line ◽  
The South ◽  
Epicentral Area ◽  
The North ◽  
San Andreas ◽  
North Side ◽  
To Come

Summary The area over which the shock was felt by persons at rest was 27,000 square miles or more, extending from Fresno on the north to San Diego on the south, and from Mojave to the coast. The epicenter seems to have been near the summit of the Tejon Pass, where the intensity reached VII or a little more, of the Rossi-Forel scale. At many places the shock was preceded by a pronounced roar like thunder or a high wind. Wherever the direction of the sound was noted it appeared to come from the epicentral area. The region is too thinly populated and our data are too meager to enable us to outline the area of high intensity with confidence, but the following facts seem to be fairly well established: The shock or shocks were produced by movement on the fault line that passes through the Tejon Pass and follows thence east-southeast along the axes of Leonas Valley and Anaverde Valley and northwestward through Cuddy Canyon and Cuddy Valley. The topographic evidence of the fault in the Tejon Pass is very pronounced, but there is topographic evidence of another fault that branches off from the Tejon Pass fault about a mile and a half northwest of Tejon Pass and runs east-northeast from the northwest corner of Los Angeles county, passing along the north side of Castac Lake. The depression occupied by Castac Lake seems to have been formed by a downthrow on the south side of this fault. It has been supposed that the fault through Tejon Pass was a southward prolongation of the San Andreas fault near San Francisco. The identity of these faults is far from being evident. The topography, the distribution of earthquake shocks, and the method of fracture along the fault zones all suggest a series of overlapping faults rather than one continuous fault. Mr. Hamlin says on this subject: “This fault is not a long continuous fracture, but rather a fault zone with numerous branches. Dropped blocks are not uncommon along this zone, some being a mile or more wide and twice as long.” The forms of the isoseismals of this particular earthquake, however, suggest definite relations to this fault zone.

Co-creation and the state in a global context

2020 ◽  
pp. 23-40
Author(s):  
Sue Brownill ◽  
Oscar Natividad Puig
Keyword(s):  
Civil Society ◽  
Mexico City ◽  
The South ◽  
Global Context ◽  
The World ◽  
Local Stakeholders ◽  
Global North ◽  
Global Nature ◽  
To Come ◽  
North And South

This chapter draws on debates about the need for theory to ‘see from the South’ (Watson, 2009) to critically reflect on the increasingly global nature of co-creation both as a focus for research and for initiatives from governments around the world. It explores whether current understandings of co-creation narratives, which have tended to come from the Global North, can adequately characterise and understand the experience from the South, and the resulting need to decolonise knowledge and conduct research into the diverse ways in which co-creation can be constituted. It goes on to illustrate these debates by exploring the differing contexts for co-creation created by state-civil society relations in the project’s participating countries. These show that, while distinct contrasts emerge, it is important to move beyond dichotomies of north and south to explore the spaces of participation and resistance that are created within different contexts and how these are navigated by projects and communities engaged in co-creation. The chapter draws on material from interviews with local stakeholders and academics involved in the Co-Creation project and project conferences in Rio, Mexico City and Berlin.

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