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Geometry


Geometry (Ancient Greek: ?e?µet??a; geo- 'earth', -metri 'measurement') 'Earth-measuring' is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space. Geometry is one of the oldest mathematical sciences. Initially a body of practical knowledge concerning lengths, areas, and volumes, in the 3rd century BC geometry was put into an axiomatic form by Euclid, whose treatment—Euclidean geometry—set a standard for many centuries to follow.

 
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Regional Melt-pond Fraction and Albedo of Thin Arctic First-year D...

By: S. A. Divina; C. A. Pedersen; S. R. Hudson; M. A. Granskog; T. I. Karlsen; D. V. Divine; A. H. H. Renner; S. Gerland

Description: Norwegian Polar Institute, Fram Centre, 9296 Tromsø, Norway. The paper presents a case study of the regional (≈150 km) morphological and optical properties of a relatively thin, 70–90 cm modal thickness, first-year Arctic sea ice pack in an advanced stage of melt. The study combines in situ broadband albedo measurements representative of the four main surface types (bare ice, dark melt ponds, bright melt ponds and open water) and images acquired by a he...

Björk, G., Stranne, C., and Borenäs, K.: The Sensitivity of the Arctic Ocean Sea Ice Thickness and Its Dependence on the Surface Albedo Parameterization, J. Climate, 26, 1355–1370, doi:10.1175/JCLI-D-12-00085.1, 2013.; Castro-Morales, K., Kauker, F., Losch, M., Hendricks, S., Riemann-Campe, K., and Gerdes, R.: Sensitivity of simulated Arctic sea ice to realistic ice thickness distributions and snow parameterizations...

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A Model Study of Abrahamsenbreen, a Surging Glacier in Northern Sp...

By: W. J. J. Van Pelt; J. Oerlemans

Description: Institute for Marine and Atmospheric Research Utrecht, Utrecht, the Netherlands. The climate sensitivity of Abrahamsenbreen, a 20 km long surge-type glacier in northern Spitsbergen, is studied with a simple glacier model. A scheme to describe the surges is included, which makes it possible to account for the effect of surges on the total mass budget of the glacier. A climate reconstruction back to AD 1300, based on ice-core data from Lomonosovfonna and ...

Fowler, A. C., Murray, T., and Ng, F. S. L.: Thermally controlled glacier surging, J. Glaciol., 42, 527–538, 2001.; Hagen, J. O., Liestøl, O., Roland, E., and Jørgensen, T.: Glacier Atlas of Svalbard and Jan Mayen, Norsk Polarinstitutt, Oslo, Meddelelser Nr. 129, 169 pp., 1993.; A\dhalgeirsdóttir, G., Björnsson, H., Pálsson, F., and Magnússon, E.: Analysis of a surging outlet glacier of Vatnajökull ice cap, Iceland, Ann. Glaciol., 42, 23–28, 2005.; Bintanja, R. and Selte...

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Modelling the 20Th and 21St Century Evolution of Hoffellsjökull Gl...

By: H. Hannesdóttir; S. Guðmundsson; H. Björnsson; T. Jóhannesson; F. Pálsson; G. Aðalgeirsdóttir; S. Þ. Sigurðsson; E. Berthier

Description: Institute of Earth Sciences, University of Iceland, 101 Reykjavík, Iceland. The Little Ice Age maximum extent of glaciers in Iceland was reached about 1890 AD and most glaciers in the country have retreated during the 20th century. A model for the surface mass balance and the flow of glaciers is used to reconstruct the 20th century retreat history of Hoffellsjökull, a south-flowing outlet glacier of Vatnajökull, which is located close to the southeast c...

A{\dh}algeirsdóttir, G.: Flow dynamics of Vatnajökull ice cap, Iceland, Mitteilung 181, Versuchsantalt fur Wasserbau, Hydrologie und Glaziologie der ETH Zurich-Zentrum, 178 pp, 2003.; A{\dh}algeirsdóttir, G., Jóhannesson, T., Björnsson, H., Pálsson, F., Sigur{\dh}sson, O.: Response of Hofsjökull and southern Vatnajökull, Iceland, to climate change, J. Geophys. Res.,{111}, F03001, doi:10.1029/2005JF000388, 2006.; A{\dh}al...

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Investigating Changes in Basal Conditions of Variegated Glacier Pr...

By: F. Gillet-chaulet; M. Nodet; O. Gagliardini; M. Jay-allemand

Description: LGGE, UMR5183, CNRS/UJF Grenoble, France. The Variegated Glacier (Alaska) is known to surge periodically after a sufficient amount of cumulative mass balance is reached, but this observation is difficult to link with changes in the basal conditions. Here, using a 10-year dataset, consisting in surface topography and surface velocity observations along a flow line for 25 dates, we have reconstructed the evolution of the basal conditions prior and during ...

Arthern, R. and Gudmundsson, G.: Initialization of ice-sheet forecasts viewed as an inverse Robin problem, J. Glaciol., 56, 527–533, 2010.; Bindschadler, R.: A Numerical Model of Temperate Glacier Flow Applied to the Quiescent Phase of a Surge-Type Glacier, J. Glaciol., 28, 239–265, 1982.; Bindschadler, R., Harrison, W. D., Raymond, C. F., and Crosson, R.: Geometry and dynamics of a surge-type glacier, J. Glaciol., 18, 181–194, 1977.; Cuffey, K. and Paterson, W. S. B.: T...

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Basal Crevasses in Larsen C Ice Shelf and Implications for Their G...

By: B. Kulessa; D. Jansen; E. C. King; D. I. Benn; A. Luckman; P. Sammonds

Description: School of the Environment and Society, Swansea University, UK. Basal crevasses extend upwards from the base of ice bodies and can penetrate more than halfway through the ice column under conditions found commonly on ice shelves. As a result, they may locally modify the exchange of mass and energy between ice shelf and ocean, and by altering the shelf's mechanical properties could play a fundamental role in ice shelf stability. Although early studies rev...

Barrett, B., Murray, T., Clark, R.: Errors in Radar CMP Velocity Estimates Due to Survey Geometry, and Their Implication for Ice Water Content Estimation, J. Environ. Eng. Geophys., 12(1), 101–111, doi:10.2113/JEEG12.1.101, 2007.; Benn, D. I. and Evans, D. J. A.: Glaciers and Glaciation, Edn. 2., London: Hodder Education; 2010.; Bassis, J. N., Coleman, R., Fricker, H. A., Minster, J. B.: Episodic propagation of a rift on...

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Stable Water Isotopes of Precipitation and Firn Cores from the Nor...

By: H. Meyer; M. Tonelli; F. Fernandoy

Description: Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association, Potsdam, Germany. In order to investigate the climate variability in the north Antarctic Peninsula region, this paper focuses on the relationship between stable isotope content of precipitation and firn, and main meteorological variables (air temperature, relative humidity, sea surface temperature, and sea ice extent). Between 2008 and 2010, we collected precipitation sa...

Carrasco, J. and González, M. (Eds.): Climatología de la Península Antártica y de la Base Presidente Eduardo Frei Montalva, Dirección Meteorológica de Chile, 2007.; Abram, N. J., Thomas, E. R., McConnell, J. R., Mulvaney, R., Bracegirdle, T. J., Sime, L. C., and Aristarain, A. J.: Ice core evidence for a 20th century decline of sea ice in the Bellingshausen Sea, Antarctica, J. Geophys. Res., 115, D23101, doi:10.1029/2010jd01...

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Thermal Conductivity of Anisotropic Snow Measured by Three Indepen...

By: F. Riche; M. Schneebeli

Description: WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland. The thermal conductivity of snow determines the temperature gradient, and by this the rate of snow metamorphism. It is therefore a key property of snow. However, parameterizations of thermal conductivity measured with the transient needle probe and the steady-state heat-flux plate show a bias. In addition, it is not clear to which degree thermal anisotropy is rele...

Abels, G.: Beobachtungen der täglichen Periode der Temperatur im Schnee und Bestimmung des Wärmeleitungsvermögens des Schnees als Function seiner Dichtigkeit, Kaiserl. Akad. Wissensch., Rep. Meteorologie, 16, 1–53, 1892.; Abu-Hamdeh, N. and Reeder, R.: Soil thermal conductivity: effects of density, moisture, salt concentration, and organic matter, Soil Sci. Soc. Am. J., 64, 1285–1290, 2000.; Ams, C. H., Knackstedt, M. A., Pinczewski, W. V., and Lindquist, W. B.: Accurate...

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A General Treatment of Snow Microstructure Exemplified by an Impro...

By: M. Schneebeli; H. Löwe; F. Riche

Description: WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland. Finding relevant microstructural parameters beyond the density is a longstanding problem which hinders the formulation of accurate parametrizations of physical properties of snow. Towards a remedy we address the effective thermal conductivity tensor of snow via known anisotropic, second-order bounds. The bound provides an explicit expression for the thermal conductivity and predi...

Arons, E. and Colbeck, S.: Geometry of heat and mass-transfer in dry snow – a review of theory and experiment, Rev. Geophys., 33, 463–493, doi:10.1029/95RG02073, 1995.; Barber, D. G. and Nghiem, S.: The role of snow on the thermal dependence of microwave backscatter over sea ice, J. Geophys. Res., 104, 789–803, 1999.; Calonne, N., Flin, F., Morin, S., Lesaffre, B., du Roscoat, S. R., and Geindreau, C.: Numerical and experim...

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Modelling Environmental Influences on Calving at Helheim Glacier, ...

By: T. Murray; A. Luckman; N. Selmes; S. Cook; A. Goldsack; I. C. Rutt; T. Zwinger

Description: Glaciology Group, Geography Department, Swansea University, Swansea, SA2 8PP, UK. Calving is an important mass-loss process for many glaciers worldwide, and has been assumed to respond to a variety of environmental influences. We present a grounded, flowline tidewater glacier model, using a physically realistic calving mechanism, which is applied to Helheim Glacier, East Greenland. By qualitatively examining both modelled size and frequency of calving e...

Amundson, J. M. and Truffer, M.: A unifying framework for iceberg-calving models, J. Glaciol., 56, 822–30, 2010.; Abdalati, W., Krabill, W., Frederick, E., Manizade, S., Martin, C., Sonntag, J., Swift, R., Thomas, R., Wright, W., and Yungel, J.: Outlet glacier and margin elevation changes: Near-coastal thinning of the Greenland Ice Sheet, J. Geophys. Res., 106, 33729–33742, 2001.; Amundson, J. M., Fahnestock, M., Truffer, M., Brown, J., Lüthi, M. P., and Motyka, R.: Ice ...

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Fracture-induced Softening for Large-scale Ice Dynamics : Volume 7...

By: T. Albrecht; A. Levermann

Description: Earth System Analysis, Potsdam Institute for Climate Impact Research, Potsdam, Germany. Floating ice shelves can exert a retentive and hence stabilizing force onto the inland ice sheet of Antarctica. However, this effect has been observed to diminish by fracture-coupled dynamic processes within the protective ice shelves leading to accelerated ice flow and hence to a sea-level contribution. In order to better understand the role of fractures in ice dynam...

Sandhäger, H., Rack, W., and Jansen, D.: Model investigations of Larsen B Ice Shelf dynamics prior to the breakup, in: FRISP Report, Vol. 16, 5–7, 2005.; Albrecht, T. and Levermann, A.: Fracture field for large-scale ice dynamics, J. Glaciol, 58, 2012.; Bamber, J. L. and Aspinall, W. P.: An expert judgement assessment of future sea level rise from the ice sheets, Nature Climate Change, 3, 424–427, doi:10.1038/nclimate1778

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Morphology and Distribution of Liquid Inclusions in Young Sea Ice ...

By: N.-x. Geilfus; L. Ryner; A. A. Hare; B. G. T. Else; D. G. Barber; R. J. Galley; D. Isleifson; S. Rysgaard

Description: Centre for Earth Observation Science, University of Manitoba, 125 Dysart Road, Winnipeg, Manitoba, R3T 2N2, Canada. In order to determine the morphology and distribution of liquid inclusions in young sea ice, magnetic resonance imaging of an 18 cm sea ice core was done using a Siemens 3T TIM TRIO human scanner. The sample was stored at about −20 °C until the beginning of a constructive interference steady state gradient echo sequence which lasted four an...

Assur, A.: Composition of sea ice and its tensile strength, US Army snow ice and permafrost research establishment, research report 44, corps of engineers, Wilmette, Illinois, December 1960.; Bennington, K. O.: Desalination features in natural sea ice, J. Glaciol., 6, 845–857, 1967; Cole, D. M. and Shapiro, L. H.: Observations of brine drainage networks and microstructure of first-year sea ice, J. Geophys. Res., 103, 21739–21750, 1998.; Cox, G. F. N. and Weeks, W. F.: Br...

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Combining Damage and Fracture Mechanics to Model Calving : Volume ...

By: J. Weiss; G. Durand; O. Gagliardini; J. Krug

Description: CNRS, LGGE, 38041 Grenoble, France. Calving of icebergs is a major negative component of polar ice-sheet mass balance. We present a new calving modeling framework relying on both continuum damage mechanics and linear elastic fracture mechanics. This combination accounts for both the slow sub-critical surface crevassing and fast propagation of crevasses when calving occurs. First, damage of the ice occurs over long timescales and enhances the viscous ...

Weiss, J. and Schulson, E. M.: Coulombic faulting from the grain scale to the geophysical scale: lessons from ice, J. Phys. D, 42, 214017, doi:10.1088/0022-3727/42/21/214017, 2009.; Xiao, J. and Jordaan, I.: Application of damage mechanics to ice failure in compression, Cold Reg. Sci. Technol., 24, 305–322, 1996.; Albrecht, T. and Levermann, A.: Fracture field for large-scale ice dynamics, J. Glaciol., 58, 165–...

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Combining Damage and Fracture Mechanics to Model Calving : Volume ...

By: J. Weiss; O. Gagliardini; G. Durand; J. Krug

Description: CNRS, LGGE, 38041 Grenoble, France. Calving of icebergs is a major negative component of polar ice-sheet mass balance. We present a new calving modeling framework relying on both continuum damage mechanics and linear elastic fracture mechanics. This combination accounts for both the slow sub-critical surface crevassing and fast propagation of crevasses when calving occurs. First, damage of the ice occurs over long timescales and enhances the visc...

Albrecht, T. and Levermann, A.: Fracture field for large-scale ice dynamics, J. Glaciol., 58, 165–177, 2012.; Andresen, C. S., Straneo, F., Ribergaard, M. H., Bjørk, A. A., Andersen, T. J., Kuijpers, A., Nørgaard-Pedersen, N., Kjær, K. H., Schjøth, F., Weckström, K., and Ahlström, A. P.: Rapid response of Helheim Glacier in Greenland to climate variability over the past century, Nat. Geosci., 5, 37–41, 2011.; Åström, J. A., Riikilä, T. I., Tallinen, T., Zwinger, T., Benn...

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Regional Albedo of Arctic First-year Drift Ice in Advanced Stages ...

By: M. A. Granskog; S. R. Hudson; C. A. Pedersen; T. I. Karlsen; D. V. Divine; S. Gerland; S. A. Divina

Description: Norwegian Polar Institute, FRAM Centre, 9296 Tromsø, Norway. The paper presents a case study of the regional (≈ 150 km) broadband albedo of first year Arctic sea ice in advanced stages of melt, estimated from a combination of in situ albedo measurements and aerial imagery. The data were collected during the eight day ICE12 drift experiment carried out by the Norwegian Polar Institute in the Arctic north of Svalbard at 82.3° N f...

Conover, W.: Practical Nonparametric Statistics, Wiley Series in Probability and Statistics, 3rd Edn., Wiley, New York, 1999.; Curry, J. A., Schramm, J. L., and Ebert, E. E.: Sea ice-albedo climate feedback mechanism, J. Climate, 8, 240–247, 2.0.CO;2>doi:10.1175/1520-0442(1995)008<0240:SIACFM>2.0.CO;2, 1995.; Derksen, C., Piwowar, J., and LeDrew, E.: Sea-ice melt-pond fraction as determined from low lev...

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Deglaciation of the Caucasus Mountains, Russia/Georgia, in the 21S...

By: S. Kutuzov; O. Rototaeva; G. Nosenko; T. Khromova; M. Shahgedanova

Description: Department of Geography and Environmental Science and Walker Institute for Climate System Research, University of Reading, Whiteknights, Reading RG6 6AB, UK. Changes in map area of 498 glaciers located in the Main Caucasus Ridge (MCR) and on Mt. Elbrus in the Greater Caucasus Mountains (Russia and Georgia) were assessed using multispectral ASTER and panchromatic Landsat imagery with 15 m spatial resolution from 1999–2001 and 2010–2012. Changes in recessi...

Andreassen, L. M., Paul, F., Kääb, A., and Hausberg, J. E.: Landsat-derived glacier inventory for Jotunheimen, Norway, and deduced glacier changes since the 1930s, The Cryosphere, 2, 131–145, doi:10.5194/tc-2-131-2008, 2008.; Arendt, A. et al.: Randolph Glacier Inventory [v2.0]: A Dataset of Global Glacier Outlines, Boulder, Colorado, Digital Media, http://www.glims.org/RGI...

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Brief Communication: Sudden Drainage of a Subglacial Lake Beneath ...

By: C. Porter; B. E. Smith; M. J. Noh; S. Jeong; I. M. Howat

Description: School of Earth Sciences and Byrd Polar Research Center, Ohio State University, Columbus, Ohio, USA. We report on the appearance of a 2 km wide, 70 m deep circular depression located 50 km inland of the southwestern margin of the Greenland Ice Sheet that provides the first direct evidence for concentrated, long-term storage, and sudden release, of meltwater at the bed. Drainage of the lake may have been triggered by the recent increase in...

Bartholomew, I., Nienow, P., Sole, A., Mair, D., Cowton, T., Palmer, S., and Wadham, J.: Supraglacial forcing of subglacial drainage in the ablation zone of the Greenland ice sheet, Geophys. Res. Lett., 38, L08502, doi:10.1029/2011GL047063, 2011.; Borsa, A. A., Moholdt, G., Fricker, H. A., and Brunt, K. M.: A range correction for ICESat and its potential impact on ice-sheet mass balance studies, The Cryosphere, 8, 345–35...

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A Model Study of Abrahamsenbreen, a Surging Glacier in Northern Sp...

By: J. Oerlemans; W. J. J. Van Pelt

Description: Institute for Marine and Atmospheric research Utrecht, Utrecht, the Netherlands. The climate sensitivity of Abrahamsenbreen, a 20 km long surge-type glacier in northern Spitsbergen, is studied with a simple glacier model. A scheme to describe the surges is included, which makes it possible to account for the effect of surges on the total mass budget of the glacier. A climate reconstruction back to AD 1300, based on ice-core data from Lomonosovfonna...

A\dhalgeirsdóttir G., Björnsson, H., Pálsson, F., and Magnússon, E.: Analysis of a surging outlet glacier of Vatnajökull ice cap, Iceland, Ann. Glaciol., 42, 23–28, 2005.; Divine, D., Isaksson, E., Martma, T., Meijer, H., Moore, J., Pohjola, V., van de Wal, R., and Godtliebsen, F.: Thousand years of winter surface air temperature variations in Svalbard and northern Norway reconstructed from ice core data, Polar Res., 30, 7379,

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Overview on Radon Measurements in Arctic Glacier Waters : Volume 9...

By: A. P. Nawrot; O. Hengesch; Z. Tosheva; A. Kies; J. Jania

Description: Laboratoire Physique des Radiations (LPR), University of Luxembourg, Luxembourg. We present a possibility to investigate the presence of the subglacial component in waters supplied by glacierized basins in introducing radioactive isotope measurements, in combination with more classical parameters like temperature and electrical conductivity. Among the natural radioactive elements the most promising is the noble gas radon isotope 222Rnv. With ...

Brown, H. G.: Glacier meltwater hydrochemistry, Appl. Geochem., 17, 855–883, 2002.; Alley, R. B., Lawson, D. E., Evenson, E. B., Strasser, J. C., Larson, G. J.: Glaciohydrologic supercooling: a freeze-on method to create stratified, debris-rich basal ice, II. Theory, J. Glaciol., 44, 563–569, 1998.; Boulton, G. S., Lunn, R., Vidstrand, P., Zatsepin, S.: Subglacial dainage by groundwater-channel coupling, and the origin of esker systems: Part I – glaciological observation...

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The Manufacturer and Builder : Volume 0006, Issue 5 May 1874: The ...

By: Western and Company

Description: The Manufacturer and Builder was a practical journal of industrial progress published monthly in the 19th century by Western and Company.

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The Manufacturer and Builder : Volume 0007, Issue 2 February 1875:...

By: Western and Company

Description: The Manufacturer and Builder was a practical journal of industrial progress published monthly in the 19th century by Western and Company.

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