Uncertainty quantification of ocean driven melting under the Pine Island ice shelf
Along the Antarctic coastline, ice shelves extend over the ocean, forming where glacial ice streams flow from the land to the sea. Ice shelves are important structures for the climate system, as they hold back land ice from reaching the ocean and contributing to sea level rise. In the Amundsen Sea r...
Main Author: | |
---|---|
Other Authors: | , , , , |
Format: | Thesis |
Language: | English |
Published: |
2021
|
Subjects: | |
Online Access: | https://hdl.handle.net/2152/115129 https://doi.org/10.26153/tsw/42030 |
id |
ftunivtexas:oai:repositories.lib.utexas.edu:2152/115129 |
---|---|
record_format |
openpolar |
spelling |
ftunivtexas:oai:repositories.lib.utexas.edu:2152/115129 2023-05-15T13:23:52+02:00 Uncertainty quantification of ocean driven melting under the Pine Island ice shelf Smith, Timothy Andrew, Ph. D. Heimbach, Patrick Ghattas, Omar Bui-Thanh, Tan Dawson, Clint Blankenship, Donald 2021-12 application/pdf https://hdl.handle.net/2152/115129 https://doi.org/10.26153/tsw/42030 en eng https://hdl.handle.net/2152/115129 http://dx.doi.org/10.26153/tsw/42030 Oceanography Uncertainty quantification Data assimilation Ocean modelling Ice-ocean interactions Amundsen Sea Antarctica Thesis text 2021 ftunivtexas https://doi.org/10.26153/tsw/42030 2022-08-04T17:27:16Z Along the Antarctic coastline, ice shelves extend over the ocean, forming where glacial ice streams flow from the land to the sea. Ice shelves are important structures for the climate system, as they hold back land ice from reaching the ocean and contributing to sea level rise. In the Amundsen Sea region of Antarctica, ice shelves are in contact with warm, subsurface ocean waters, which is likely a key driver of high meltrates, thinning, and glacial mass loss. Numerical models of the ocean circulation in the Amundsen Sea have been essential for building our understanding of the mechanisms responsible for heat delivery and meltrate response. However, these computational models are subject to a host of uncertainties stemming from the representation of external forcing and unresolved physical processes. The primary goal of this work is to address this issue. We develop a numerical model of the ocean circulation in the cavity formed by the Pine Island ice shelf, which is fed by one of the fastest flowing glaciers in Antarctica. We then formulate a two-stage Bayesian inverse problem in which we constrain the open boundary conditions of the model to the sparsely available observations of the ocean state in Pine Island Bay. In the inference problem we specify our prior uncertainty according to Gaussian statistics. We build off of previous work to develop a general covariance model that is appropriate for applications with complex boundaries, multivariate control parameters, and highly anisotropic length scales - a common scenario in oceanography. In the first stage of the inference problem we solve an optimal interpolation problem to inform an initial estimate of the mean and posterior uncertainty of the open boundary conditions. We use this initial estimate to refine the nonlinear forward model configuration. We evaluate the sub ice shelf cavity circulation and meltrate response to parameterizations of (1) subgrid-scale ocean turbulence and (2) ice-ocean interactions. We find that a recently developed parameterization ... Thesis Amundsen Sea Antarc* Antarctic Antarctica Ice Shelf Ice Shelves Pine Island Pine Island Bay Sea ice The University of Texas at Austin: Texas ScholarWorks Antarctic The Antarctic Amundsen Sea Island Bay ENVELOPE(-109.085,-109.085,59.534,59.534) Pine Island Bay ENVELOPE(-102.000,-102.000,-74.750,-74.750) |
institution |
Open Polar |
collection |
The University of Texas at Austin: Texas ScholarWorks |
op_collection_id |
ftunivtexas |
language |
English |
topic |
Oceanography Uncertainty quantification Data assimilation Ocean modelling Ice-ocean interactions Amundsen Sea Antarctica |
spellingShingle |
Oceanography Uncertainty quantification Data assimilation Ocean modelling Ice-ocean interactions Amundsen Sea Antarctica Smith, Timothy Andrew, Ph. D. Uncertainty quantification of ocean driven melting under the Pine Island ice shelf |
topic_facet |
Oceanography Uncertainty quantification Data assimilation Ocean modelling Ice-ocean interactions Amundsen Sea Antarctica |
description |
Along the Antarctic coastline, ice shelves extend over the ocean, forming where glacial ice streams flow from the land to the sea. Ice shelves are important structures for the climate system, as they hold back land ice from reaching the ocean and contributing to sea level rise. In the Amundsen Sea region of Antarctica, ice shelves are in contact with warm, subsurface ocean waters, which is likely a key driver of high meltrates, thinning, and glacial mass loss. Numerical models of the ocean circulation in the Amundsen Sea have been essential for building our understanding of the mechanisms responsible for heat delivery and meltrate response. However, these computational models are subject to a host of uncertainties stemming from the representation of external forcing and unresolved physical processes. The primary goal of this work is to address this issue. We develop a numerical model of the ocean circulation in the cavity formed by the Pine Island ice shelf, which is fed by one of the fastest flowing glaciers in Antarctica. We then formulate a two-stage Bayesian inverse problem in which we constrain the open boundary conditions of the model to the sparsely available observations of the ocean state in Pine Island Bay. In the inference problem we specify our prior uncertainty according to Gaussian statistics. We build off of previous work to develop a general covariance model that is appropriate for applications with complex boundaries, multivariate control parameters, and highly anisotropic length scales - a common scenario in oceanography. In the first stage of the inference problem we solve an optimal interpolation problem to inform an initial estimate of the mean and posterior uncertainty of the open boundary conditions. We use this initial estimate to refine the nonlinear forward model configuration. We evaluate the sub ice shelf cavity circulation and meltrate response to parameterizations of (1) subgrid-scale ocean turbulence and (2) ice-ocean interactions. We find that a recently developed parameterization ... |
author2 |
Heimbach, Patrick Ghattas, Omar Bui-Thanh, Tan Dawson, Clint Blankenship, Donald |
format |
Thesis |
author |
Smith, Timothy Andrew, Ph. D. |
author_facet |
Smith, Timothy Andrew, Ph. D. |
author_sort |
Smith, Timothy Andrew, Ph. D. |
title |
Uncertainty quantification of ocean driven melting under the Pine Island ice shelf |
title_short |
Uncertainty quantification of ocean driven melting under the Pine Island ice shelf |
title_full |
Uncertainty quantification of ocean driven melting under the Pine Island ice shelf |
title_fullStr |
Uncertainty quantification of ocean driven melting under the Pine Island ice shelf |
title_full_unstemmed |
Uncertainty quantification of ocean driven melting under the Pine Island ice shelf |
title_sort |
uncertainty quantification of ocean driven melting under the pine island ice shelf |
publishDate |
2021 |
url |
https://hdl.handle.net/2152/115129 https://doi.org/10.26153/tsw/42030 |
long_lat |
ENVELOPE(-109.085,-109.085,59.534,59.534) ENVELOPE(-102.000,-102.000,-74.750,-74.750) |
geographic |
Antarctic The Antarctic Amundsen Sea Island Bay Pine Island Bay |
geographic_facet |
Antarctic The Antarctic Amundsen Sea Island Bay Pine Island Bay |
genre |
Amundsen Sea Antarc* Antarctic Antarctica Ice Shelf Ice Shelves Pine Island Pine Island Bay Sea ice |
genre_facet |
Amundsen Sea Antarc* Antarctic Antarctica Ice Shelf Ice Shelves Pine Island Pine Island Bay Sea ice |
op_relation |
https://hdl.handle.net/2152/115129 http://dx.doi.org/10.26153/tsw/42030 |
op_doi |
https://doi.org/10.26153/tsw/42030 |
_version_ |
1766376003438903296 |