High Depolarization Ratios of Naturally Occurring Cirrus Clouds Near Air Traffic Regions Over Europe

Abstract Cirrus clouds have a large influence on the Earth's climate and anthropogenic activities such as aviation can alter their properties. Besides the formation of contrails, indirect effects on naturally occurring cirrus like increased heterogeneous freezing due to exhaust soot particles a...

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Main Authors: Benedikt Urbanek, Silke Groß, Martin Wirth, Christian Rolf, Martina Krämer, Christiane Voigt
Format: Article
Language:English
Published: Wiley 2018-12-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2018GL079345
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author Benedikt Urbanek
Silke Groß
Martin Wirth
Christian Rolf
Martina Krämer
Christiane Voigt
author_facet Benedikt Urbanek
Silke Groß
Martin Wirth
Christian Rolf
Martina Krämer
Christiane Voigt
author_sort Benedikt Urbanek
collection DOAJ
description Abstract Cirrus clouds have a large influence on the Earth's climate and anthropogenic activities such as aviation can alter their properties. Besides the formation of contrails, indirect effects on naturally occurring cirrus like increased heterogeneous freezing due to exhaust soot particles are discussed in the literature. However, hardly any observational study exists. In this work we present cirrus optical properties measured by an airborne lidar over Europe during the Midlatitude Cirrus experiment (ML‐CIRRUS). One half of the cloud cases showed elevated depolarization ratios with a mode difference of 10 percentage points indicating differences in the clouds microphysical properties. Their origin can be traced back to highly frequented air traffic regions, and they show lower in‐cloud ice supersaturations. Our analysis reveals no influence of embedded contrails and temperature. These results could be explained by an indirect aerosol effect where heterogeneous freezing is caused by aviation exhaust particles.
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institution DOAJ
issn 0094-8276
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language English
publishDate 2018-12-01
publisher Wiley
record_format Article
series Geophysical Research Letters
spelling doaj-art-cd0abb1ea7c843a0b60daba037194e2d2025-08-20T03:09:42ZengWileyGeophysical Research Letters0094-82761944-80072018-12-01452313,16613,17210.1029/2018GL079345High Depolarization Ratios of Naturally Occurring Cirrus Clouds Near Air Traffic Regions Over EuropeBenedikt Urbanek0Silke Groß1Martin Wirth2Christian Rolf3Martina Krämer4Christiane Voigt5Institut für Physik der Atmosphäre Deutsches Zentrum für Luft‐ und Raumfahrt e.V Oberpfaffenhofen GermanyInstitut für Physik der Atmosphäre Deutsches Zentrum für Luft‐ und Raumfahrt e.V Oberpfaffenhofen GermanyInstitut für Physik der Atmosphäre Deutsches Zentrum für Luft‐ und Raumfahrt e.V Oberpfaffenhofen GermanyInstitut für Energie‐ und Klimaforschung (IEK‐7) Forschungszentrum Jülich GmbH Jülich GermanyInstitut für Energie‐ und Klimaforschung (IEK‐7) Forschungszentrum Jülich GmbH Jülich GermanyInstitut für Physik der Atmosphäre Deutsches Zentrum für Luft‐ und Raumfahrt e.V Oberpfaffenhofen GermanyAbstract Cirrus clouds have a large influence on the Earth's climate and anthropogenic activities such as aviation can alter their properties. Besides the formation of contrails, indirect effects on naturally occurring cirrus like increased heterogeneous freezing due to exhaust soot particles are discussed in the literature. However, hardly any observational study exists. In this work we present cirrus optical properties measured by an airborne lidar over Europe during the Midlatitude Cirrus experiment (ML‐CIRRUS). One half of the cloud cases showed elevated depolarization ratios with a mode difference of 10 percentage points indicating differences in the clouds microphysical properties. Their origin can be traced back to highly frequented air traffic regions, and they show lower in‐cloud ice supersaturations. Our analysis reveals no influence of embedded contrails and temperature. These results could be explained by an indirect aerosol effect where heterogeneous freezing is caused by aviation exhaust particles.https://doi.org/10.1029/2018GL079345aerosol indirect effect on ice clouds
spellingShingle Benedikt Urbanek
Silke Groß
Martin Wirth
Christian Rolf
Martina Krämer
Christiane Voigt
High Depolarization Ratios of Naturally Occurring Cirrus Clouds Near Air Traffic Regions Over Europe
Geophysical Research Letters
aerosol indirect effect on ice clouds
title High Depolarization Ratios of Naturally Occurring Cirrus Clouds Near Air Traffic Regions Over Europe
title_full High Depolarization Ratios of Naturally Occurring Cirrus Clouds Near Air Traffic Regions Over Europe
title_fullStr High Depolarization Ratios of Naturally Occurring Cirrus Clouds Near Air Traffic Regions Over Europe
title_full_unstemmed High Depolarization Ratios of Naturally Occurring Cirrus Clouds Near Air Traffic Regions Over Europe
title_short High Depolarization Ratios of Naturally Occurring Cirrus Clouds Near Air Traffic Regions Over Europe
title_sort high depolarization ratios of naturally occurring cirrus clouds near air traffic regions over europe
topic aerosol indirect effect on ice clouds
url https://doi.org/10.1029/2018GL079345
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AT martinwirth highdepolarizationratiosofnaturallyoccurringcirruscloudsnearairtrafficregionsovereurope
AT christianrolf highdepolarizationratiosofnaturallyoccurringcirruscloudsnearairtrafficregionsovereurope
AT martinakramer highdepolarizationratiosofnaturallyoccurringcirruscloudsnearairtrafficregionsovereurope
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