Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes
Understanding the effect warming has on ice sheets is vital for accurate projections of climate change. A better understanding of how the Antarctic ice sheets have changed size and shape in the past would allow us to improve our predictions of how they may adapt in the future; this is of particular...
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ftwhiterose:oai:etheses.whiterose.ac.uk:28246 2023-05-15T13:50:32+02:00 Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes Turner, Fiona 2020-08 text https://etheses.whiterose.ac.uk/28246/ https://etheses.whiterose.ac.uk/28246/1/Thesis-Turner-160136687-FINAL.pdf en eng https://etheses.whiterose.ac.uk/28246/1/Thesis-Turner-160136687-FINAL.pdf Turner, Fiona (2020) Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes. PhD thesis, University of Sheffield. cc_by_nc_nd_4 CC-BY-NC-ND Thesis NonPeerReviewed 2020 ftwhiterose 2023-01-30T21:28:23Z Understanding the effect warming has on ice sheets is vital for accurate projections of climate change. A better understanding of how the Antarctic ice sheets have changed size and shape in the past would allow us to improve our predictions of how they may adapt in the future; this is of particular relevance in predicting future global sea level changes. This research makes use of previous reconstructions of the ice sheets, ice core data and Bayesian methods to create a model of the Antarctic ice sheet at the Last Glacial Maximum (LGM). We do this by finding the relationship between the ice sheet shape and water isotope values. We developed a prior model which describes the variation between a set of ice sheet reconstructions at the LGM. A set of ice sheet shapes formed using this model was determined by a consultation with experts and run through the general circulation model HadCM3, providing us with paired data sets of ice sheet shapes and water isotope estimates. The relationship between ice sheet shape and water isotopes is explored using a Gaussian process emulator of HadCM3, building a statistical distribution describing the shape of the ice sheets given the isotope values outputted by the climate model. We then use MCMC to sample from the posterior distribution of the ice sheet shape and attempt to find a shape that creates isotopic values matching as closely as possible to the observations collected from ice cores. This allows us to quantify the uncertainty in the shape and incorporate expert beliefs about the Antarctic ice sheet during this time period. Our results suggests that the AIS may have been thicker at the LGM that previous reconstructions predict. Thesis Antarc* Antarctic ice core Ice Sheet White Rose eTheses Online (Universities Leeds, Sheffield, York) Antarctic The Antarctic |
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White Rose eTheses Online (Universities Leeds, Sheffield, York) |
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English |
description |
Understanding the effect warming has on ice sheets is vital for accurate projections of climate change. A better understanding of how the Antarctic ice sheets have changed size and shape in the past would allow us to improve our predictions of how they may adapt in the future; this is of particular relevance in predicting future global sea level changes. This research makes use of previous reconstructions of the ice sheets, ice core data and Bayesian methods to create a model of the Antarctic ice sheet at the Last Glacial Maximum (LGM). We do this by finding the relationship between the ice sheet shape and water isotope values. We developed a prior model which describes the variation between a set of ice sheet reconstructions at the LGM. A set of ice sheet shapes formed using this model was determined by a consultation with experts and run through the general circulation model HadCM3, providing us with paired data sets of ice sheet shapes and water isotope estimates. The relationship between ice sheet shape and water isotopes is explored using a Gaussian process emulator of HadCM3, building a statistical distribution describing the shape of the ice sheets given the isotope values outputted by the climate model. We then use MCMC to sample from the posterior distribution of the ice sheet shape and attempt to find a shape that creates isotopic values matching as closely as possible to the observations collected from ice cores. This allows us to quantify the uncertainty in the shape and incorporate expert beliefs about the Antarctic ice sheet during this time period. Our results suggests that the AIS may have been thicker at the LGM that previous reconstructions predict. |
format |
Thesis |
author |
Turner, Fiona |
spellingShingle |
Turner, Fiona Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes |
author_facet |
Turner, Fiona |
author_sort |
Turner, Fiona |
title |
Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes |
title_short |
Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes |
title_full |
Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes |
title_fullStr |
Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes |
title_full_unstemmed |
Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes |
title_sort |
ice cores and emulation: learning more about past ice sheet shapes |
publishDate |
2020 |
url |
https://etheses.whiterose.ac.uk/28246/ https://etheses.whiterose.ac.uk/28246/1/Thesis-Turner-160136687-FINAL.pdf |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic ice core Ice Sheet |
genre_facet |
Antarc* Antarctic ice core Ice Sheet |
op_relation |
https://etheses.whiterose.ac.uk/28246/1/Thesis-Turner-160136687-FINAL.pdf Turner, Fiona (2020) Ice Cores and Emulation: Learning More About Past Ice Sheet Shapes. PhD thesis, University of Sheffield. |
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cc_by_nc_nd_4 |
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CC-BY-NC-ND |
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