Loading…

Impacts of Cloud Droplet–Nucleating Aerosols on Shallow Tropical Convection

Low-level warm-phase clouds cover a substantial portion of Earth's oceans and play an important role in the global water and energy budgets. The characteristics of these clouds are controlled by the large-scale environment, boundary layer conditions, and cloud microphysics. Variability in the c...

Full description

Saved in:
Bibliographic Details
Published in:Journal of the atmospheric sciences 2015-04, Vol.72 (4), p.1369-1385
Main Authors: Saleeby, Stephen M, Herbener, Stephen R, van den Heever, Susan C, L'Ecuyer, Tristan
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Low-level warm-phase clouds cover a substantial portion of Earth's oceans and play an important role in the global water and energy budgets. The characteristics of these clouds are controlled by the large-scale environment, boundary layer conditions, and cloud microphysics. Variability in the concentration of aerosols can alter cloud microphysical and precipitation processes that subsequently impact the system dynamics and thermodynamics and thereby create aerosol-cloud dynamic-thermodynamic feedback effects. In this study, three distinct cloud regimes were simulated, including stratocumulus, low-level cumulus (cumulus under stratocumulus), and deeper cumulus clouds. The simulations were conducted without environmental large-scale forcing, thereby allowing all three cloud types to freely interact with the environmental state in an undamped fashion. Increases in aerosol concentration in these unforced, warm-phase, tropical cloud simulations lead to the production of fewer low-level cumuli; thinning and erosion of the widespread stratocumulus layer; and the development of deeper, inversion-penetrating cumuli. The mechanisms for these changes are explored. Despite the development of deeper, more heavily precipitating cumuli, the reduction of the widespread moderately precipitating stratocumulus clouds leads to an overall reduction in domainwide accumulated precipitation when aerosol concentrations are enhanced.
ISSN:0022-4928
1520-0469
DOI:10.1175/JAS-D-14-0153.1