Arctic low-level boundary layer clouds: in situ measurements and simulations of mono- and bimodal supercooled droplet size distributions at the top layer of liquid phase clouds

Publication type:
Journal article
Metadata:
Autoren
  • M Klingebiel
  • A de Lozar
  • S Molleker
  • R Weigel
  • A Roth
  • L Schmidt
  • J Meyer
  • A Ehrlich
  • R Neuber
  • M Wendisch
  • S Borrmann
Autoren-URL
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=fis-test-1&SrcAuth=WosAPI&KeyUT=WOS:000347958500004&DestLinkType=FullRecord&DestApp=WOS_CPL
DOI
10.5194/acp-15-617-2015
eISSN
1680-7324
Externe Identifier
  • Clarivate Analytics Document Solution ID: AZ0TT
ISSN
1680-7316
Ausgabe der Veröffentlichung
2
Zeitschrift
ATMOSPHERIC CHEMISTRY AND PHYSICS
Paginierung
617 - 631
Datum der Veröffentlichung
2015
Status
Published
Titel
Arctic low-level boundary layer clouds: in situ measurements and simulations of mono- and bimodal supercooled droplet size distributions at the top layer of liquid phase clouds
Sub types
  • Article
Ausgabe der Zeitschrift
15

Data source: Web of Science (Lite)

Other metadata sources:
Abstract
<jats:p>Abstract. Aircraft borne optical in situ size distribution measurements were performed within Arctic boundary layer clouds with a special emphasis on the cloud top layer during the VERtical Distribution of Ice in Arctic clouds (VERDI) campaign in April and May 2012. An instrumented Basler BT-67 research aircraft operated out of Inuvik over the Mackenzie River delta and the Beaufort Sea in the Northwest Territories of Canada. Besides the cloud particle and hydrometeor size spectrometers the aircraft was equipped with instrumentation for aerosol, radiation and other parameters. Inside the cloud, droplet size distributions with monomodal shapes were observed for predominantly liquid-phase Arctic stratocumulus. With increasing altitude inside the cloud the droplet mean diameters grew from 10 to 20 μm. In the upper transition zone (i.e., adjacent to the cloud-free air aloft) changes from monomodal to bimodal droplet size distributions (Mode 1 with 20 μm and Mode 2 with 10 μm diameter) were observed. It is shown that droplets of both modes co-exist in the same (small) air volume and the bimodal shape of the measured size distributions cannot be explained as an observational artifact caused by accumulating data point populations from different air volumes. The formation of the second size mode can be explained by (a) entrainment and activation/condensation of fresh aerosol particles, or (b) by differential evaporation processes occurring with cloud droplets engulfed in different eddies. Activation of entrained particles seemed a viable possibility as a layer of dry Arctic enhanced background aerosol (which was detected directly above the stratus cloud) might form a second mode of small cloud droplets. However, theoretical considerations and model calculations (adopting direct numerical simulation, DNS) revealed that, instead, turbulent mixing and evaporation of larger droplets are the most likely reasons for the formation of the second droplet size mode in the uppermost region of the clouds. </jats:p>
Autoren
  • M Klingebiel
  • A de Lozar
  • S Molleker
  • R Weigel
  • A Roth
  • L Schmidt
  • J Meyer
  • A Ehrlich
  • R Neuber
  • M Wendisch
  • S Borrmann
DOI
10.5194/acp-15-617-2015
eISSN
1680-7324
Ausgabe der Veröffentlichung
2
Zeitschrift
Atmospheric Chemistry and Physics
Sprache
en
Online publication date
2015
Paginierung
617 - 631
Status
Published online
Herausgeber
Copernicus GmbH
Herausgeber URL
http://dx.doi.org/10.5194/acp-15-617-2015
Datum der Datenerfassung
2021
Titel
Arctic low-level boundary layer clouds: in situ measurements and simulations of mono- and bimodal supercooled droplet size distributions at the top layer of liquid phase clouds
Ausgabe der Zeitschrift
15

Data source: Crossref

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