Please enable JavaScript.
Coggle requires JavaScript to display documents.
Focussed Melt (Likely Cause Thwaites Ice Shelf Rifting (Goldberg theorises…
Focussed Melt
Likely Cause Thwaites Ice Shelf Rifting
Goldberg theorises
Rifting roughly coincident w/lake drainage
Cold freshwater input - adds buoyancy
∴ Mobilises warm water & generates turbulence
Fast water flow - catalysed melt?
High melt rates thinned ice shelf
∴ increased susceptibility to weakening
Channelised
Melt Obvs
Gourmelen 2017
Thinning along margin Dotson ice shelf
Cause: channelised ocean melt
(evinced by Goldberg et al 2012 model)
Warm water = self organised
∴ focussed melt along one margin
Cuts channels along ice shelf margin
Melt/channel reinforced by preferential water flow through channel
--> Positive feedback
Is Dotson Unstable?
Gourmelen 2017
Does channelised melt make it unstable?
Channel may melt through ice shelf
-->
on one side in 25 years
n.b. forward in time projection (maintaining current rates) ∴ no ice dynamics considered
∴ 170 years for whole ice shelf to melt
(if spatially averaged melt rates uniform)
Dotson
Ice Shelf
Warm ice shelf in middle of Amundsen Sea
exposed to Circumpolar deepwater
Fast melt rates ~8 m/yr
Melting Location Importance
Thwaites Ice Tongue has sped up
since separated from slower E ice shelf
Rifting occured btwn
Thwaites ice tongue
Thwaites E ice shelf
What caused rift / weakening?
Melting ?
Buoyancy from lake drainage?
= rougly coincident with speedup
Melt rate
pattern
under Dotson
Previously
= crude pattern inferred from radar
Cryosat observations elucidated pattern
high resolution 2011-2016 thining obv
showed thinning along margins
Focussed Melt Importance
Can make ice shelfs unstable
∴ Susceptible to complete collapse