Contrail cirrus radiative forcing for future air traffic
<p>The climate impact of air traffic is to a large degree caused by changes in cirrus cloudiness resulting from the formation of contrails. Contrail cirrus radiative forcing is expected to increase significantly over time due to the large projected increases in air traffic. We use ECHAM5-CCMod...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-06-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/19/8163/2019/acp-19-8163-2019.pdf |
| _version_ | 1819237989943869440 |
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| author | L. Bock U. Burkhardt |
| author_facet | L. Bock U. Burkhardt |
| author_sort | L. Bock |
| collection | DOAJ |
| description | <p>The climate impact of air traffic is to a large degree
caused by changes in cirrus cloudiness resulting from the formation of
contrails. Contrail cirrus radiative forcing is expected to increase
significantly over time due to the large projected increases in air traffic.
We use ECHAM5-CCMod, an atmospheric climate model with an online contrail
cirrus parameterization including a microphysical two-moment scheme, to
investigate the climate impact of contrail cirrus for the year 2050. We take
into account the predicted increase in air traffic volume, changes in
propulsion efficiency and emissions, in particular soot emissions, and the
modification of the contrail cirrus climate impact due to anthropogenic
climate change.</p>
<p>Global contrail cirrus radiative forcing increases by a factor of 3 from
2006 to 2050, reaching 160 or even 180 mW m<span class="inline-formula"><sup>−2</sup></span>, which is the result of the increase in air traffic volume and a slight shift in air traffic towards higher altitudes. Large increases in contrail cirrus radiative forcing are
expected over all of the main air traffic areas, but relative increases are
largest over main air traffic areas over eastern Asia. The projected upward
shift in air traffic attenuates contrail cirrus radiative forcing increases
in the midlatitudes but reinforces it in the tropical areas. Climate change
has an insignificant impact on global contrail cirrus radiative forcing,
while regional changes are significant. Of the emission reductions it is the
soot number emission reductions by 50 % that lead to a significant
decrease in contrail cirrus optical depth and coverage, leading to a
decrease in radiative forcing by approximately 15 %. The strong increase
in contrail cirrus radiative forcing due to the projected increase in air
traffic volume cannot be compensated for by the decrease in initial ice
crystal numbers due to reduced soot emissions and improvements in
propulsion efficiency.</p> |
| first_indexed | 2024-12-23T13:29:06Z |
| format | Article |
| id | doaj.art-583e82fc8ef848adb10ff6365dd8adf5 |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-23T13:29:06Z |
| publishDate | 2019-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-583e82fc8ef848adb10ff6365dd8adf52022-12-21T17:45:14ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242019-06-01198163817410.5194/acp-19-8163-2019Contrail cirrus radiative forcing for future air trafficL. BockU. Burkhardt<p>The climate impact of air traffic is to a large degree caused by changes in cirrus cloudiness resulting from the formation of contrails. Contrail cirrus radiative forcing is expected to increase significantly over time due to the large projected increases in air traffic. We use ECHAM5-CCMod, an atmospheric climate model with an online contrail cirrus parameterization including a microphysical two-moment scheme, to investigate the climate impact of contrail cirrus for the year 2050. We take into account the predicted increase in air traffic volume, changes in propulsion efficiency and emissions, in particular soot emissions, and the modification of the contrail cirrus climate impact due to anthropogenic climate change.</p> <p>Global contrail cirrus radiative forcing increases by a factor of 3 from 2006 to 2050, reaching 160 or even 180 mW m<span class="inline-formula"><sup>−2</sup></span>, which is the result of the increase in air traffic volume and a slight shift in air traffic towards higher altitudes. Large increases in contrail cirrus radiative forcing are expected over all of the main air traffic areas, but relative increases are largest over main air traffic areas over eastern Asia. The projected upward shift in air traffic attenuates contrail cirrus radiative forcing increases in the midlatitudes but reinforces it in the tropical areas. Climate change has an insignificant impact on global contrail cirrus radiative forcing, while regional changes are significant. Of the emission reductions it is the soot number emission reductions by 50 % that lead to a significant decrease in contrail cirrus optical depth and coverage, leading to a decrease in radiative forcing by approximately 15 %. The strong increase in contrail cirrus radiative forcing due to the projected increase in air traffic volume cannot be compensated for by the decrease in initial ice crystal numbers due to reduced soot emissions and improvements in propulsion efficiency.</p>https://www.atmos-chem-phys.net/19/8163/2019/acp-19-8163-2019.pdf |
| spellingShingle | L. Bock U. Burkhardt Contrail cirrus radiative forcing for future air traffic Atmospheric Chemistry and Physics |
| title | Contrail cirrus radiative forcing for future air traffic |
| title_full | Contrail cirrus radiative forcing for future air traffic |
| title_fullStr | Contrail cirrus radiative forcing for future air traffic |
| title_full_unstemmed | Contrail cirrus radiative forcing for future air traffic |
| title_short | Contrail cirrus radiative forcing for future air traffic |
| title_sort | contrail cirrus radiative forcing for future air traffic |
| url | https://www.atmos-chem-phys.net/19/8163/2019/acp-19-8163-2019.pdf |
| work_keys_str_mv | AT lbock contrailcirrusradiativeforcingforfutureairtraffic AT uburkhardt contrailcirrusradiativeforcingforfutureairtraffic |