 |
| Titel |
Dehydration effects from contrails in a coupled contrail–climate model |
| VerfasserIn |
U. Schumann, J. E. Penner, Yibin Chen, Cheng Zhou, K. Graf |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 19 ; Nr. 15, no. 19 (2015-10-08), S.11179-11199 |
| Datensatznummer |
250120084
|
| Publikation (Nr.) |
 copernicus.org/acp-15-11179-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| The uptake of water by contrails in ice-supersaturated air and the release of
water after ice particle advection and sedimentation dehydrates the
atmosphere at flight levels and redistributes humidity mainly to lower
levels. The dehydration is investigated by coupling a plume-scale
contrail model with a global aerosol–climate model. The contrail model
simulates all the individual contrails forming from global air traffic
for meteorological conditions as defined by the climate model. The
computed contrail cirrus properties compare reasonably with
theoretical concepts and observations. The mass of water in aged
contrails may exceed 106 times the mass of water emitted from
aircraft. Many of the ice particles sediment and release water in the
troposphere, on average 700 m below the mean flight
levels. Simulations with and without coupling are compared. The drying
at contrail levels causes thinner and longer-lived contrails with
about 15 % reduced contrail radiative forcing (RF). The reduced RF
from contrails is on the order of 0.06 W m−2, slightly larger
than estimated earlier because of higher soot emissions. For normal
traffic, the RF from dehydration is small compared to interannual
variability. A case with emissions increased by 100 times is used to
overcome statistical uncertainty. The contrails impact the entire
hydrological cycle in the atmosphere by reducing the total water
column and the cover by high- and low-level clouds. For normal traffic,
the dehydration changes contrail RF by positive shortwave and negative
longwave contributions on the order of 0.04 W m−2, with a small
negative net RF. The total net RF from contrails and dehydration
remains within the range of previous estimates. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|