Further evidence for CCN aerosol concentrations determining the height of warm rain and ice initiation in convective clouds over the Amazon basin

Publikationstyp:
Zeitschriftenaufsatz
Metadaten:
Autoren
  • Ramon Campos Braga
  • Daniel Rosenfeld
  • Ralf Weigel
  • Tina Jurkat
  • Meinrat O Andreae
  • Manfred Wendisch
  • Ulrich Poeschl
  • Christiane Voigt
  • Christoph Mahnke
  • Stephan Borrmann
  • Rachel I Albrecht
  • Sergej Molleker
  • Daniel A Vila
  • Luiz AT Machado
  • Lucas Grulich
Autoren-URL
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=fis-test-1&SrcAuth=WosAPI&KeyUT=WOS:000417073800003&DestLinkType=FullRecord&DestApp=WOS_CPL
DOI
10.5194/acp-17-14433-2017
eISSN
1680-7324
Externe Identifier
  • Clarivate Analytics Document Solution ID: FO7RM
ISSN
1680-7316
Ausgabe der Veröffentlichung
23
Zeitschrift
ATMOSPHERIC CHEMISTRY AND PHYSICS
Paginierung
14433 - 14456
Datum der Veröffentlichung
2017
Status
Published
Titel
Further evidence for CCN aerosol concentrations determining the height of warm rain and ice initiation in convective clouds over the Amazon basin
Sub types
  • Article
Ausgabe der Zeitschrift
17

Datenquelle: Web of Science (Lite)

Andere Metadatenquellen:
Abstract
<jats:p>Abstract. We have investigated how aerosols affect the height above cloud base of rain and ice hydrometeor initiation and the subsequent vertical evolution of cloud droplet size and number concentrations in growing convective cumulus. For this purpose we used in situ data of hydrometeor size distributions measured with instruments mounted on HALO aircraft during the ACRIDICON–CHUVA campaign over the Amazon during September 2014. The results show that the height of rain initiation by collision and coalescence processes (Dr, in units of meters above cloud base) is linearly correlated with the number concentration of droplets (Nd in cm−3) nucleated at cloud base (Dr ≈ 5 ⋅ Nd). Additional cloud processes associated with Dr, such as GCCN, cloud, and mixing with ambient air and other processes, produce deviations of  ∼  21 % in the linear relationship, but it does not mask the clear relationship between Dr and Nd, which was also found at different regions around the globe (e.g., Israel and India). When Nd exceeded values of about 1000 cm−3, Dr became greater than 5000 m, and the first observed precipitation particles were ice hydrometeors. Therefore, no liquid water raindrops were observed within growing convective cumulus during polluted conditions. Furthermore, the formation of ice particles also took place at higher altitudes in the clouds in polluted conditions because the resulting smaller cloud droplets froze at colder temperatures compared to the larger drops in the unpolluted cases. The measured vertical profiles of droplet effective radius (re) were close to those estimated by assuming adiabatic conditions (rea), supporting the hypothesis that the entrainment and mixing of air into convective clouds is nearly inhomogeneous. Additional CCN activation on aerosol particles from biomass burning and air pollution reduced re below rea, which further inhibited the formation of raindrops and ice particles and resulted in even higher altitudes for rain and ice initiation. </jats:p>
Autoren
  • Ramon Campos Braga
  • Daniel Rosenfeld
  • Ralf Weigel
  • Tina Jurkat
  • Meinrat O Andreae
  • Manfred Wendisch
  • Ulrich Pöschl
  • Christiane Voigt
  • Christoph Mahnke
  • Stephan Borrmann
  • Rachel I Albrecht
  • Sergej Molleker
  • Daniel A Vila
  • Luiz AT Machado
  • Lucas Grulich
DOI
10.5194/acp-17-14433-2017
eISSN
1680-7324
Ausgabe der Veröffentlichung
23
Zeitschrift
Atmospheric Chemistry and Physics
Sprache
en
Online publication date
2017
Paginierung
14433 - 14456
Status
Published online
Herausgeber
Copernicus GmbH
Herausgeber URL
http://dx.doi.org/10.5194/acp-17-14433-2017
Datum der Datenerfassung
2020
Titel
Further evidence for CCN aerosol concentrations determining the height of warm rain and ice initiation in convective clouds over the Amazon basin
Ausgabe der Zeitschrift
17

Datenquelle: Crossref

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