Model-data comparison of Antarctic winter sea-ice extent and Southern
Ocean sea-surface temperatures during Marine Isotope Stage 5e
Marine Isotope Stage (MIS) 5e (130-116 ka) represents a ‘process
analogue’ for future anthropogenic warming. Climate model simulations
for MIS 5e have previously failed to produce Southern Ocean sea-surface
temperatures (SST) and sea-ice extent reconstructed from marine sediment
core proxy records. Here we compare state of the art HadGEM3 and HadCM3
simulations of Peak MIS 5e Southern Ocean summer SST and September
sea-ice concentrations with the latest marine sediment core proxy data.
The model outputs and proxy records show the least consistency in the
regions located near the present-day Southern Ocean gyre boundaries,
implying that model simulations are currently unable to fully realise
changes in gyre extent and position during MIS 5e. Including Heinrich 11
meltwater forcing in Peak MIS 5e climate simulations improves the
likeness to proxy data but it is clear that longer (3-4 ka) run times
are required to fully test the consistency between models and data.