Effects of solid aerosols on partially glaciated clouds

Research output: Contribution to journalArticle

Abstract

Sensitivity tests were conducted using a state-of-the-art aerosol–cloud to investigate the key microphysical and dynamical mechanisms by which solid aerosols affect glaciated clouds. The tests involved simulations of two contrasting cases of deep convection—a tropical maritime case and a midlatitude continental case, in which solid aerosol concentrations were increased from their pre-industrial (1850) to their present-day (2010) levels. In the midlatitude continental case, the boosting of the number concentrations of solid aerosols weakened the updrafts in deep convective clouds, resulting in reduced snow and graupel production. Consequently, the cloud fraction and the cloud optical thickness increased with increasing ice nuclei (IN), causing a negative radiative flux change at the top of the atmosphere (TOA), that is, a cooling effect of −1.96 ± 0.29 W/m2. On the other hand, in the tropical maritime case, increased ice nuclei invigorated upper-tropospheric updrafts in both deep convective and stratiform clouds, causing cloud tops to shift upwards. Snow production was also intensified, resulting in reduced cloud fraction and cloud optical thickness, hence a positive radiative flux change at the TOA—a warming effect of 1.02 ± 0.36 W/m2 was predicted.

Details

Authors
Organisations
External organisations
  • Finnish Meteorological Institute
  • University of Leeds
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Meteorology and Atmospheric Sciences

Keywords

  • aerosol–cloud interactions, cloud microphysics, cloud-resolving models, clouds, glaciated clouds, indirect effects
Original languageEnglish
Pages (from-to)2634-2649
Number of pages16
JournalQuarterly Journal of the Royal Meteorological Society
Volume144
Issue number717
Publication statusPublished - 2018
Publication categoryResearch
Peer-reviewedYes