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Ice-sheet models

Welsh Ice Cap

A high-resolution 3D thermomechanical model was used to simulate the Welsh Ice Cap independently over the last glacial cycle. The model was forced using climate curves derived from the GISP2 ice core record (see figure). After running a suite of >400 simulations, two ‘optimum’ experiments were found that best represented the available empirical evidence for glaciation of the Welsh landscape.

The first, E397, was driven by a 2-phase climate whereby temperature suppression over the glacial-maximum period was enhanced (max. ~2°C) relative to the preceding and proceeding climate:

The second, E426, is a slight modification on the experiment above, whereby temperatures were suppressed (max. 0.2ºC) prior to the glacial maximum as well. The modelled Welsh Ice Cap subsequently experiences two major advances over the glacial cycle (~30 and 23.5 ka):

Download E397 | Download E426

3 comments to “Ice-sheet models”

  • The Welsh Ice Cap | henrypatton.org, April 14, 2014 at 12:16

    […] Ice-sheet models […]

  • Brian John, August 12, 2011 at 07:17

    Henry, these are fascinating. The second simulation, with two expansion phases, should be testable by reference to stratigraphy in the field. How much evidence is there for two layers of Devensian till with something periglacial in between them?

    • Henry, August 12, 2011 at 15:09

      Offshore drilling in Tremadoc Bay (Garrard & Dobson, 1974) revealed a tripartite sequence of Welsh – Irish sea – Welsh till…no dating though. There are tripartite sequences on the Lleyn too, but these have a multitude of interpretations.
      I don’t claim that either simulation is more ‘correct’ than the other…of course with the Irish Sea Ice Stream things would have been a bit different.