In:
Climate of the Past, Copernicus GmbH, Vol. 17, No. 3 ( 2021-05-20), p. 1065-1089
Abstract:
Abstract. The Last Glacial Maximum (LGM, ∼ 21 000 years ago)
has been a major focus for evaluating how well state-of-the-art climate
models simulate climate changes as large as those expected in the future
using paleoclimate reconstructions. A new generation of climate models has
been used to generate LGM simulations as part of the Paleoclimate Modelling
Intercomparison Project (PMIP) contribution to the Coupled Model
Intercomparison Project (CMIP). Here, we provide a preliminary analysis and
evaluation of the results of these LGM experiments (PMIP4, most of which are PMIP4-CMIP6) and compare them with the previous generation of simulations
(PMIP3, most of which are PMIP3-CMIP5). We show that the global averages of the
PMIP4 simulations span a larger range in terms of mean annual surface air
temperature and mean annual precipitation compared to the PMIP3-CMIP5
simulations, with some PMIP4 simulations reaching a globally colder and
drier state. However, the multi-model global cooling average is similar for
the PMIP4 and PMIP3 ensembles, while the multi-model PMIP4 mean annual
precipitation average is drier than the PMIP3 one. There are important
differences in both atmospheric and oceanic circulations between the two
sets of experiments, with the northern and southern jet streams being more
poleward and the changes in the Atlantic Meridional Overturning Circulation
being less pronounced in the PMIP4-CMIP6 simulations than in the PMIP3-CMIP5
simulations. Changes in simulated precipitation patterns are influenced by
both temperature and circulation changes. Differences in simulated climate
between individual models remain large. Therefore, although there are
differences in the average behaviour across the two ensembles, the new
simulation results are not fundamentally different from the PMIP3-CMIP5
results. Evaluation of large-scale climate features, such as land–sea
contrast and polar amplification, confirms that the models capture these
well and within the uncertainty of the paleoclimate reconstructions.
Nevertheless, regional climate changes are less well simulated: the models
underestimate extratropical cooling, particularly in winter, and
precipitation changes. These results point to the utility of using
paleoclimate simulations to understand the mechanisms of climate change and
evaluate model performance.
Type of Medium:
Online Resource
ISSN:
1814-9332
DOI:
10.5194/cp-17-1065-2021
DOI:
10.5194/cp-17-1065-2021-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2217985-9
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