Repository logo

Infoscience

  • English
  • French
Log In
Logo EPFL, École polytechnique fédérale de Lausanne

Infoscience

  • English
  • French
Log In
  1. Home
  2. Academic and Research Output
  3. Journal articles
  4. Global impact of mineral dust on cloud droplet number concentration
 
research article

Global impact of mineral dust on cloud droplet number concentration

Karydis, V. A.
•
Tsimpidi, A. P.
•
Bacer, S.
Show more
2017
Atmospheric Chemistry And Physics

The importance of wind-blown mineral dust for cloud droplet formation is studied by considering (i) the adsorption of water on the surface of insoluble particles, (ii) particle coating by soluble material (atmospheric aging) which augments cloud condensation nuclei (CCN) activity, and (iii) the effect of dust on inorganic aerosol concentrations through thermodynamic interactions with mineral cations. The ECHAM5/MESSy Atmospheric Chemistry (EMAC) model is used to simulate the composition of global atmospheric aerosol, while the ISORROPIA-II thermodynamic equilibrium model treats the interactions of K+-Ca2+-Mg2+-NH+ 4 -Na+-SO2- 4 -NO- 3 -Cl--H2O aerosol with gas-phase inorganic constituents. Dust is considered a mixture of inert material with reactive minerals and its emissions are calculated online by taking into account the soil particle size distribution and chemical composition of different deserts worldwide. The impact of dust on droplet formation is treated through the "unified dust activation parameterization" that considers the inherent hydrophilicity from adsorption and acquired hygroscopicity from soluble salts during aging. Our simulations suggest that the presence of dust increases cloud droplet number concentration (CDNC) over major deserts (e.g., up to 20% over the Sahara and the Taklimakan desert) and decreases CDNC over polluted areas (e.g., up to 10% over southern Europe and 20% over northeastern Asia). This leads to a global net decrease in CDNC by 11 %. The adsorption activation of insoluble aerosols and the mineral dust chemistry are shown to be equally important for the cloud droplet formation over the main deserts; for example, these effects increase CDNC by 20% over the Sahara. Remote from deserts the application of adsorption theory is critically important since the increased water uptake by the large aged dust particles (i.e., due to the added hydrophilicity by the soluble coating) reduce the maximum supersaturation and thus cloud droplet formation from the relatively smaller anthropogenic particles (e.g., CDNC decreases by 10% over southern Europe and 20% over northeastern Asia by applying adsorption theory). The global average CDNC decreases by 10% by considering adsorption activation, while changes are negligible when accounting for the mineral dust chemistry. Sensitivity simulations indicate that CDNC is also sensitive to the mineral dust mass and inherent hydrophilicity, and not to the chemical composition of the emitted dust. © Author(s) 2017.

  • Files
  • Details
  • Metrics
Loading...
Thumbnail Image
Name

17-5601-2017-acp-17-5601-2017.pdf

Type

Publisher's Version

Version

http://purl.org/coar/version/c_970fb48d4fbd8a85

Access type

openaccess

License Condition

CC BY

Size

7.69 MB

Format

Adobe PDF

Checksum (MD5)

d2218bf0298fc7ac59b791bd73cd7020

Logo EPFL, École polytechnique fédérale de Lausanne
  • Contact
  • infoscience@epfl.ch

  • Follow us on Facebook
  • Follow us on Instagram
  • Follow us on LinkedIn
  • Follow us on X
  • Follow us on Youtube
AccessibilityLegal noticePrivacy policyCookie settingsEnd User AgreementGet helpFeedback

Infoscience is a service managed and provided by the Library and IT Services of EPFL. © EPFL, tous droits réservés