The Antarctic icesheet : an analog for Northern hemisphere paleo-icesheets? in Models in geomorphology.
How glaciological processes can interact to control global ice-sheet fluctuations during a glacial cycle and where analogies with the Arctic can be drawn.
Calculating basal temperatures in icesheets : an excel spreadsheet method
Antarctica ; Glaciology ; Ice ; Icesheet ; Model ; Numerical model ; Quaternary ; Scotland ; Temperature ; Thermal regime ; United Kingdom
The flow of icesheets and their geomorphological impact is greatly influenced by their basal thermal regime. In this paper the AA. introduce an Excel spreadsheet method for calculating basal ice temperature along a one-dimensional flowline
of an icesheet. The first example provides a calculation of basal thermal regime beneath the north eastern part of the Scottish icesheet during the last glacial maximum, the second shows how basal ice temperatures can be calculated beneath the modern
Continental icesheets and the planetary radiation budget
The interaction between continental icesheets and the planetary radiation budget is potentially important in climate-sensitivity studies. A simple ice-sheet model incorporated in an energy-balance climate model provides a tool for studying
this interaction in a quantitative way. Experiments in which the ice-sheet model is coupled step by step to the climate model show that icesheets hardly affect the zonal mean radiation balance because the albedo feedback due to sea ice and snow cover is dominating
. The model requires a 5% drop in the solar constant to create icesheets of ice-age size. If the feedback between surface elevation and ice-mass balance is included (in very crude way), the ice-sheet size (L, mesured southward from 70N) becomes much more
sensitive to insolation. For a range of normalized solar constants, roughly from 0.98 to 1.02, two stable solutions exist: L0 and L2000 km. This result demonstrates that the response of icesheets to insolation variations is far from linear. It also stresses
the need for explicit modeling of the ice-mass balance of icesheets, particularly its dependence on surface elevation.
The case for a stable East Antarctic IceSheet: the background
The case for a stable East Antarctic IceSheet
Antarctica ; Climatic variation ; Glacial features ; Global change ; Icesheet ; Sea level ; Tectonics ; Volcanism
There are two primary views concerning the stability of the East Antarctic IceSheet. After summarising the status of the two hypotheses, the AA. explain the rationale for this volume. Building on the Vega Symposium of April 1993, it presents
the case for the stability of the East Antarctic IceSheet and includes new work on terrestrial geomorphology and geology, marine cores and ice-sheet modelling.
Climatic variation ; Forecast;Prediction ; Glacial features ; Glacier mass balance ; Icesheets;Ice cap;Inlandsis ; Model ; Scotland ; Topography ; United Kingdom
This paper uses a numerical icesheet model to investigate the role of topography in influencing ice sheat growth. The model is applied to the maritime, mid-latitutde uplands of Scotland and relies on a series of assumptions about mass balance
, topography, and ice flow. It is driven by an imposed pattern of temperature change. The model is able to predict effectively the extent and thickness of the Loch Lomond icesheet, using a palaeotemperature curve based on Coleoptera assemblages.
In this article, the nature, origin and uses of internal Antarctic ice-sheet layering, observed on 60 MHz RES data, are investigated. In doing so an insight into several aspects of modern Antarctic glaciological research is provided : correlating
ice cores; boundary conditions for numerical models to help determine the direction of ice flow; and means of identifying the three-dimensional ice-sheet geometry and architecture.
East Antarctic IceSheet sensitivity to Pliocene climatic change from a dry valleys perspective
The case for a stable East Antarctic IceSheet
Antarctica ; Cenozoic ; Deglaciation ; Glacial features ; Global change ; Icesheet ; Palaeoclimate ; Pliocene ; Tectonics
The AA. examine the proposition that the East Antartic IceSheet collapsed during intervals of excess Pliocene warmth. They start by reviewing the hypothesis of Pliocene deglaciation. This hypothesis yields certain prediction concerning Pliocene
paleoclimate and icesheet history. Then they test these predictions from an examination of landscape development and surficial sediments in the Dry Valleys sector of the Transantarctic Mountains.
A conceptual model for growth and decay of the Cordilleran IceSheet
British Columbia ; Canada ; Climatic variation ; Glacial features ; Glacier fluctuation ; Icesheet;Ice cap;Inlandsis ; Model ; Quaternary
The objective of this paper is to present the general concepts that have been developed and used to explain the general pattern of growth and decay of the Cordilleran IceSheet.
On the use of glacial striae for reconstruction of paleo-icesheet flow patterns - with application to the Scandinavian icesheet
The methods used to extract ice flow directions from striae data are discussed. The present paper is an attempt to highlight some crucial points and propose a practicable terminology. A stepwise analysis procedure for large-scale striae patterns
Glaciological modelling of the Late Cenozoic East Antarctic icesheet: stability or dynamism?
The case for a stable East Antarctic IceSheet
Antarctica ; Cenozoic ; Climatic variation ; Glacial features ; Glacier mass balance ; Icesheet ; Model
Two widely different hypotheses have been proposed for the late Tertiary glacial history of East Antarctica. These invoke icesheet reconstructions ranging from severe glaciation completely burying the Transantarctic Mountains to a situation
, in which an unstable East Antarctic IceSheet repeatedly collapses to produce ice-free conditions over interior basins. Experiments were performed with a 3-D model of the Antarctic IceSheet to determine the icesheet geometries to be expected under various
Modelling the effect of topography on icesheet erosion, Scotland
Glacial erosion ; Ice ; Inland ice ; Model ; Quaternary ; Scotland ; Temperature ; Topography ; United Kingdom
The aim of this paper is to use the spatial variation in icesheet erosion under former Scottish icesheets to test the hypothesis that basal thermal regime is the crucial factor determining the ability of an icesheet to erode its bed. The study
Late Devensian ice-sheet in the western Grampians, Scotland
A radial pattern of ice flow of the last ice-sheet in the largest source area of ice in the British Isles is demonstrated by the dispersal of indicator erratics and by patterns of striae, friction cracks and ice-moulded landforms.
Changes in ice-margin processes and sediment routing during ice-sheet advance across a marginal moraine
Glacial features ; Glacier fluctuation ; Greenland ; Icesheet ; Model ; Moraine ; Palaeogeography ; Quaternary ; Sediment budget
Advance of part of the margin of the Greenland icesheet across a proglacial moraine ridge between 1968 and 2002 caused progressive changes in moraine morphology, basal ice formation, debris release, ice-marginal sediment storage, and sediment
Antarctica ; Cold area ; Glacier dynamics ; Glaciology ; Global change ; Icesheet ; Model ; Sea level ; Temperature
Although the mechanics and qualitative dynamics of grounded icesheets and ice shelves are fairly well understood, this is not true for the transition between the two. In consequence, the existence and nature of any grounding line instability have
yet to be established. Further problems are understanding how uncertainties in input parameters affect results, and obtaining optimal techniques for parameter inference using ice-sheet models.
Glacial features ; Icesheet;Ice cap;Inlandsis ; Quaternary ; Salt tectonics ; United States
of the salt-bearing bed has been overridden by massive icesheets. From central New York through northeastern Ohio, southwestern Ohio, and the southern peninsula of Michigan, up-dip edges of salt basins are in areas covered by successive Pleistocene icesheets.
A paleoclimate model of Northern Hemisphere icesheets
A model for predicting the growth and decay of icesheets based on the astronomical theory of climate change is presented. The purpose of the study in part is to isolate the role of the ice-sheet physics and earth response under varying ice load
by simplifying to the extreme the role of the hydrosphere-atmosphere... The model prediction lends support to the hypothesis that the nonlinearity of the ice-sheet physics is responsible for the 100,000-yr periodicity in the geological record of the late