Fast responses on pre-industrial climate from present-day aerosols in a CMIP6 multi-model study
<p>In this work, we use Coupled Model Intercomparison Project Phase 6 (CMIP6) simulations from 10 Earth system models (ESMs) and general circulation models (GCMs) to study the fast climate responses on pre-industrial climate, due to present-day aerosols. All models carried out two sets of simu...
| Main Authors: | , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-07-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/20/8381/2020/acp-20-8381-2020.pdf |
| Summary: | <p>In this work, we use Coupled Model Intercomparison
Project Phase 6 (CMIP6) simulations from 10 Earth system models (ESMs) and
general circulation models (GCMs) to study the fast climate responses on
pre-industrial climate, due to present-day aerosols. All models carried out
two sets of simulations: a control experiment with all forcings set to the
year 1850 and a perturbation experiment with all forcings identical to the
control, except for aerosols with precursor emissions set to the year 2014.
In response to the pattern of all aerosols effective radiative forcing
(ERF), the fast temperature responses are characterized by cooling over the
continental areas, especially in the Northern Hemisphere, with the largest
cooling over East Asia and India, sulfate being the dominant aerosol surface
temperature driver for present-day emissions. In the Arctic there is a
warming signal for winter in the ensemble mean of fast temperature
responses, but the model-to-model variability is large, and it is presumably
linked to aerosol-induced circulation changes. The largest fast
precipitation responses are seen in the tropical belt regions, generally
characterized by a reduction over continental regions and presumably a
southward shift of the tropical rain belt. This is a characteristic and
robust feature among most models in this study, associated with weakening of
the monsoon systems around the globe (Asia, Africa and America) in response
to hemispherically asymmetric cooling from a Northern Hemisphere aerosol
perturbation, forcing possibly the Intertropical Convergence Zone (ITCZ) and
tropical precipitation to shift away from the cooled hemisphere despite that
aerosols' effects on temperature and precipitation are only partly realized
in these simulations as the sea surface temperatures are kept fixed. An
interesting feature in aerosol-induced circulation changes is a
characteristic dipole pattern with intensification of the Icelandic Low and
an<span id="page8382"/> anticyclonic anomaly over southeastern Europe, inducing warm air
advection towards the northern polar latitudes in winter.</p> |
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| ISSN: | 1680-7316 1680-7324 |