Sökning: "ice-sheet dynamics"

Visar resultat 1 - 5 av 24 avhandlingar innehållade orden ice-sheet dynamics.

1. 1. Computational Ice Sheet Dynamics : Error control and efficiency

   Författare :Josefin Ahlkrona; Per Lötstedt; Jesse Johnson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ice sheet modelling; stokes equations; shallow ice approximation; finite element method; perturbation expansions; non-newtonian fluids; free surface flow; Scientific Computing; Beräkningsvetenskap;

   Sammanfattning : Ice sheets, such as the Greenland Ice Sheet or Antarctic Ice Sheet, have a fundamental impact on landscape formation, the global climate system, and on sea level rise. The slow, creeping flow of ice can be represented by a non-linear version of the Stokes equations, which treat ice as a non-Newtonian, viscous fluid. LÄS MER

3. 2. Palaeo-ice streams in the north-eastern Laurentide Ice Sheet

   Författare :Hernán De Angelis; Johan Kleman; Krister Jansson; Colm O'Cofaigh; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ice sheet; ice stream; palaeo-ice sheet; palaeo-ice stream; glaciology; palaeoglaciology; Laurentide Ice Sheet; Physical geography; Naturgeografi; geografi med naturgeografisk inriktning; Physical Geography;

   Sammanfattning : 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. LÄS MER

4. 3. Numerical ice sheet modeling : Forward and inverse problems

   Författare :Gong Cheng; Lina von Sydow; Per Lötstedt; Nina Kirchner; Irina Tezaur; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; ice sheet modeling; finite element method; grounding line migration; inverse problems; adjoint method; Scientific Computing; Beräkningsvetenskap;

   Sammanfattning : Ice sheets have strong influence on the climate system. Numerical simulation provides a mathematical tool to study the ice dynamics in the past and to predict their contribution to climate change in the future. Large scale ice sheets behave as incompressible non-Newtonian fluid. LÄS MER

5. 4. Late Quaternary ice sheet history and dynamics in central and southern Scandinavia

   Författare :Timothy Johnsen; Helena Alexanderson; James T. Teller; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Scandinavian ice sheet; ice sheet dynamics; luminescence dating; cosmogenic exposure dating; geochronology; moraine; interstadial; deglaciation; nunatak; Quaternary geology; Kvartärgeologi; kvartärgeologi; Quarternary Geology;

   Sammanfattning : Recent work suggests an emerging new paradigm for the Scandinavian ice sheet (SIS); one of a dynamically fluctuating ice sheet. This doctoral research project explicitly examines the history and dynamics of the SIS at four sites within Sweden and Norway, and provides results covering different time periods of glacial history. LÄS MER

7. 5. Stability of the free-surface problem arising in ice-sheet- and glacier modeling : Numerical investigation and stabilization

   Författare :André Löfgren; Josefin Ahlkrona; Fabien Gillet-Chaulet; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Ice-sheet modeling; glacier modeling; ice-sheet dynamics; free-surface flow; stability; stabilization; free-surface stabilization algorithm; Numerical Analysis; numerisk analys;

   Sammanfattning : This thesis consists of two papers dealing with a stabilization method for free-surface flows. The method was initially developed to stabilize mantle-convection simulations, but is in this work extended to ice-sheet- and glacier modeling. LÄS MER