Sea-level fingerprints, the spatial patterns of sea level change resulting from rapid
melting of glaciers and ice sheets, play an important role in understanding past and
projecting future changes in relative sea level (RSL). Over century timescales, the
viscous flow of Earth’s interior is a small component of the total deformation due to
ice loading in most regions, so fingerprints computed using elastic Earth models are
accurate. However, in regions where the viscosity is orders of magnitude lower than
the global average, the viscous component of deformation can be significant, in which
case it is important to consider models of viscoelastic deformation.
There is evidence that the glaciated regions of Alaska, Western Canada and USA,
and the Southern Andes are situated on top of mantle regions in which the local
viscosity is several orders of magnitude lower than typical global mean values. The
goal of this work is to determine the importance of viscous flow in computing RSL
fingerprints associated with future ice mass loss from these regions. Version 5.0 of
the Randolph Glacier Inventory is used to estimate the ice load distribution required
for calculating sea-level fingerprints. For the glaciated regions that have lower than
average viscosity, fingerprints were calculated using an elastic Earth model and a 3D
viscoelastic model to quantify the influence of viscous flow on the predicted sea level
changes. Using glacier mass loss values for the intermediate future climate scenario
Representative Concentration Pathway (RCP) 4.5, the global sea level response was
computed at 2100 CE relative to 2010 CE due to melting from all glacier regions. On
comparing the results of the two models it was found that ice-load-induced viscous
flow contributes significantly (more than a few cm) to the RSL fingerprints only in
near-field regions. However, in these regions, the non-elastic contribution can be 10s
of cm. For example, at Juneau, USA the elastic calculation gave relative sea level
changes of ∼ −45 cm, compared to ∼ −120 cm based on the viscoelastic calculation.
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/40403 |
| Date | 20 April 2020 |
| Creators | Bartholet, Alan |
| Contributors | Milne, Glenn Antony |
| Publisher | Université d'Ottawa / University of Ottawa |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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