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Influence of soot number emissions on contrail cirrus properties, life cycle and climate impact

Bier, Andreas and Burkhardt, Ulrike (2016) Influence of soot number emissions on contrail cirrus properties, life cycle and climate impact. In: International Conference on clouds and precipitation. International Conference on Clouds and Precipitation 2016, 25-29 July 2016, Manchester, UK. (Unpublished)

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Contrail cirrus modify upper tropospheric cloudiness significantly. Aircraft soot emissions have a large impact on microphysical process rates of contrail cirrus. Our objective is to analyze the influence of reduced soot particle emissions, as expected from biofuels or lean combustion, on contrail cirrus properties, life cycle and climate impact. Our study is based on a contrail cirrus parameterization, using a double moment microphysics scheme, within the ECHAM5 climate model. We perform idealized process studies prescribing constant initial ice crystal number concentrations and investigate life cycles of contrail cirrus clusters in different synoptic situations and flight levels. In long-lived and large-scale ice supersaturated areas, sedimentation of ice crystals into subsaturated areas accounts for 25 to 45% of the overall ice crystal loss limiting the lifetime of contrail cirrus. At low ice crystal number concentrations, ice crystals grow initially faster, sedimentation is increased and, later in the life cycle, ice crystal number concentrations are earlier so low that deposition on ice crystals is limited by diffusional growth time scales. The influence of soot emission reductions is largest in large-scale ice supersaturated areas: A reduction in initial ice crystal number concentration by 80 % leads to an increase in ice particle loss due to sedimentation by about 15%. This means that on average, contrail cirrus lifetimes appear to be shorter by 3 to 4 hours, the mean optical depth is significantly reduced and the maxima of total extinction of short wave radiation are decreased by a factor of 2 to 2.5.

Item URL in elib:https://elib.dlr.de/109732/
Document Type:Conference or Workshop Item (Poster)
Title:Influence of soot number emissions on contrail cirrus properties, life cycle and climate impact
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Date:28 July 2016
Journal or Publication Title:International Conference on clouds and precipitation
Refereed publication:No
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Keywords:aircraft emissions, ice microphysics, climate impact
Event Title:International Conference on Clouds and Precipitation 2016
Event Location:Manchester, UK
Event Type:international Conference
Event Dates:25-29 July 2016
Organizer:University of Manchester
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:air traffic management and operations
DLR - Research area:Aeronautics
DLR - Program:L AO - Air Traffic Management and Operation
DLR - Research theme (Project):L - Climate, Weather and Environment (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics
Deposited By: Bier, Andreas
Deposited On:09 Jan 2017 13:19
Last Modified:09 Jan 2017 13:19

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