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| Titel |
How Will Aerosol-Cloud Interactions Change in an Ice-Free Arctic Summer? |
| VerfasserIn |
Anina Gilgen, Wan Ting Katty Huang, Luisa Ickes, Ulrike Lohmann |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127704
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| Publikation (Nr.) |
 EGU/EGU2016-7608.pdf |
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| Zusammenfassung |
| Future temperatures in the Arctic are expected to increase more than the global mean
temperature, which will lead to a pronounced retreat in Arctic sea ice. Before mid-century,
most sea ice will likely have vanished in late Arctic summers. This will allow ships to cruise
in the Arctic Ocean, e.g. to shorten their transport passage or to extract oil. Since both ships
and open water emit aerosol particles and precursors, Arctic clouds and radiation may be
affected via aerosol-cloud and cloud-radiation interactions. The change in radiation feeds
back on temperature and sea ice retreat. In addition to aerosol particles, also the
temperature and the open ocean as a humidity source should have a strong effect on
clouds.
The main goal of this study is to assess the impact of sea ice retreat on the Arctic climate with
focus on aerosol emissions and cloud properties. To this purpose, we conducted ensemble
runs with the global climate model ECHAM6-HAM2 under present-day and future (2050)
conditions. ECHAM6-HAM2 was coupled with a mixed layer ocean model, which includes a
sea ice model. To estimate Arctic aerosol emissions from ships, we used an elaborated ship
emission inventory (Peters et al. 2011); changes in aerosol emissions from the ocean are
calculated online.
Preliminary results show that the sea salt aerosol and the dimethyl sulfide burdens over the
Arctic Ocean significantly increase. While the ice water path decreases, the total water path
increases. Due to the decrease in surface albedo, the cooling effect of the Arctic clouds
becomes more important in 2050. Enhanced Arctic shipping has only a very small
impact. The increase in the aersol burden due to shipping is less pronounced than the
increase due to natural emissions even if the ship emissions are increased by a
factor of ten. Hence, there is hardly an effect on clouds and radiation caused by
shipping.
References
Peters et al. (2011), Atmos. Chem. Phys., 11, 5305-5320 |
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