White Rose University Consortium logo
University of Leeds logo University of Sheffield logo York University logo

Modelling the early-Holocene Laurentide Ice Sheet collapse and abrupt climate change: implications for the 8.2 ka event

Matero, Ilkka Seppo Olavi (2018) Modelling the early-Holocene Laurentide Ice Sheet collapse and abrupt climate change: implications for the 8.2 ka event. PhD thesis, University of Leeds.

[img] Text (PhD Thesis of Ilkka Seppo Olavi Matero)
Matero_ISO_EarthandEnvironment_PhD_2018.pdf - Final eThesis - complete (pdf)
Restricted until 1 February 2020.

Request a copy

Abstract

Recent research suggested that the deglaciation of an ice saddle connecting three ice domes around Hudson Bay ˜8.5 ka produced a large meltwater pulse. The resulting freshwater input to the North Atlantic was proposed as having caused the most pronounced climate change event of the Holocene, the 8.2 ka event. However, modelling experiments focussing on this saddle collapse meltwater and its climatic impact have not yet been carried out. This thesis aims to establish whether such a meltwater pulse could have forced the 8.2 ka event, and if so, to better constrain the pulse through climate and ice sheet modelling. A series of HadCM3 general circulation model -simulations was performed using idealised freshwater forcing scenarios designed to represent the centennial-length saddle collapse meltwater flux. The simulations demonstrated that the saddle collapse meltwaterwas likely the primary cause of the 8.2 ka event. An appropriate model setup for simulating early-Holocene Laurentide Ice Sheet evolution was then developed using the BISICLES ice sheet model, and an ensemble of simulations of the period 10–7.5 ka was run. An ice saddle collapse is simulated as part of the deglaciation, and the resulting meltwater pulse is in agreement with the timing of North Atlantic surface freshening signals, but is longer and less pronounced than the forcing used in the HadCM3 scenarios that best matched the climate-proxy data. The findings suggest that the BISICLES model setup simulates a dynamically realistic meltwater pulse, but there is a mismatch between the simulated pulse and the forcing necessary for reproducing the 8.2 ka event with HadCM3. Future work should further develop the BISICLES model setup as outlined in the thesis in order to refine the constraints of the meltwater pulse. This could allow for using the 8.2 ka event for assessing the sensitivity of general circulation models to ocean circulation perturbations.

Item Type: Thesis (PhD)
Related URLs:
Keywords: Ice sheet modelling, Climate modelling, Ice sheet modelling, Laurentide ice sheet, 8.2 ka event, AMOC, BISICLES, HadCM3
Academic Units: The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds)
The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Earth Sciences (Leeds)
The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Institute for Atmospheric Science (Leeds)
Depositing User: Dr ISO Matero
Date Deposited: 17 Jan 2019 12:21
Last Modified: 17 Jan 2019 12:21
URI: http://etheses.whiterose.ac.uk/id/eprint/22575

Please use the 'Request a copy' link(s) above to request this thesis. This will be sent directly to someone who may authorise access.
You can contact us about this thesis. If you need to make a general enquiry, please see the Contact us page.

Actions (repository staff only: login required)