Publication Date:
2017-11-20
Description:
Two interglacial epochs are included in the suite
of Paleoclimate Modeling Intercomparison Project (PMIP4)
simulations in the Coupled Model Intercomparison Project
(CMIP6). The experimental protocols for simulations of the
mid-Holocene (midHolocene, 6000 years before present) and
the Last Interglacial (lig127k, 127 000 years before present)
are described here. These equilibrium simulations are designed
to examine the impact of changes in orbital forcing
at times when atmospheric greenhouse gas levels were similar
to those of the preindustrial period and the continental
configurations were almost identical to modern ones. These
simulations test our understanding of the interplay between
radiative forcing and atmospheric circulation, and the connections
among large-scale and regional climate changes giving
rise to phenomena such as land–sea contrast and highlatitude
amplification in temperature changes, and responses
of the monsoons, as compared to today. They also provide an
opportunity, through carefully designed additional sensitivity
experiments, to quantify the strength of atmosphere, ocean,
cryosphere, and land-surface feedbacks. Sensitivity experiments
are proposed to investigate the role of freshwater forcing
in triggering abrupt climate changes within interglacial
epochs. These feedback experiments naturally lead to a focus
on climate evolution during interglacial periods, which
will be examined through transient experiments. Analyses
of the sensitivity simulations will also focus on interactions
between extratropical and tropical circulation, and the relationship
between changes in mean climate state and climate
variability on annual to multi-decadal timescales. The comparative
abundance of paleoenvironmental data and of quantitative
climate reconstructions for the Holocene and Last Interglacial
make these two epochs ideal candidates for systematic
evaluation of model performance, and such comparisons
will shed new light on the importance of external feedbacks
(e.g., vegetation, dust) and the ability of state-of-the-art models
to simulate climate changes realistically.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
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isiRev
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