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- De Angelis, Hernán, 1974-
(författare)
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El Manto de Hielo Antártico: estructura interna, dinámica y estabilidad
- 2009. - 1
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Ingår i: El agua en el norte de la Península Antártica. - Buenos Aires : Fundación de Historia Natural Félix de Azara. - 9789872212186 ; , s. 105-130
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- El Manto de Hielo Antártico, la cubierta glaciaria del Continente Antártico, es la mayor extensión de hielo actual de nuestro planeta y la mayor reserva de agua potable. En este capítulo se describen sus características glaciológicas principales y la de los elementos que la integran de acuerdo a los estudios y compilaciones más recientes. Se ha puesto énfasis en los aspectos dinámicos de cada uno de los componentes y en sus interrelaciones dentro del manto de hielo en su conjunto. Por último, se presenta el paradigma de la inestabilidad del Manto de Hielo Antártico Occidental y se discute la potencial evolución futura a la luz de los últimos hallazgos en la materia.
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| 2. |
- De Angelis, Hernán, 1974-
(författare)
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Hypsometry and sensitivity of the mass balance to changes in equilibrium-line altitude : the case of the Southern Patagonia Icefield
- 2014
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Ingår i: Journal of Glaciology. - 0022-1430 .- 1727-5652. ; 60:219, s. 14-28
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Tidskriftsartikel (refereegranskat)abstract
- We study the relation between glacier hypsometry and sensitivity of mass-balance rate to changes in equilibrium line altitude (ELA). Our aim is to assess whether hypsometry can be reliably used as an estimator of the sensitivity of unmeasured glaciers to changes in ELA. We express the sensitivity of mass-balance rate to ELA, \(d\dot{B}/dELA\), as a function of accumulation-area ratio (AAR), its derivative against altitude, \(dAAR/dELA\), and mass-balance functions of ELA. We then apply the concept to 139 glaciers in the Southern Patagonia Icefield for which we derive hypsometry and AAR, and analyze the influence of hypsometry on their mass-balance rate sensitivity. We confirm that glaciers where the bulk of area is located above the ELA are the least sensitive, whereas those where the bulk of area is located below the ELA are the most sensitive. Glaciers with unimodal hypsometric curves where the peak of area fraction is around the present ELA, and glaciers with bi- or multimodal area distributions, with the ELA located approximately between the bulges, have intermediate sensitivities. We conclude that hypsometry can be used as a first order estimator of the mass-balance rate sensitivity to ELA change.
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| 3. |
- De Angelis, Hernán, 1974-
(författare)
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Palaeo-ice streams in the north-eastern Laurentide Ice Sheet
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents a palaeoglaciological study aimed to determine the location, geometry and temporal evolution of palaeo-ice streams of the north-easternmost Laurentide Ice Sheet. The work was accomplished through the geomorphological interpretation of satellite imagery over 3.19 x 106 km2 of the Canadian Arctic, using a glaciological inversion scheme. Ice streams were active in this region during most of the time between the Last Glacial Maximum and the last deglaciation. A web of ice streams and inter-ice stream areas existed. Three major ice stream networks are identified: the M'Clintock Channel, Gulf of Boothia – Lancaster Sound and Hudson Strait. The M'Clintock Channel bears the most complex landform record, comprising three generations of palaeo-ice streams. Their location was weakly controlled by the subglacial topography and their geometry was determined by frozen-bed portions of the ice sheet, thus providing evidence for pure ice streams in the Laurentide Ice Sheet. In contrast, the more pronounced relief of the Gulf of Boothia – Lancaster Sound corridor supported topographically controlled ice streams. The landform record on emerged land along Hudson Strait is insufficient to support the existence of ice streams. It is therefore proposed that ice streams were constrained within the deep parts of the strait while flanked by cold-based zones on the margins. Small transient ice streams on Baffin and Prince of Wales islands drained local remnant ice caps during the collapse of the ice sheet. Analysis of the controls on the location and flow of palaeo-ice streams suggests that the interaction between the subglacial topography and thermal state of the substrate plays a more fundamental role than the geology. It is concluded that the behaviour of ice streams cannot be explained in terms of environmental controls alone, but the complex dynamics of ice stream shear margins and onset zones must be considered.
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