We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Aerosol-cloud interactions in mixed-phase convective clouds. Part 2: Meteorological ensemble.
- Authors
Miltenberger, Annette K.; Field, Paul R.; Hill, Adrian A.; Shipway, Ben J.; Wilkinson, Jonathan M.
- Abstract
The relative contribution of variations in meteorological and aerosol initial and boundary conditions to the variability in modelled cloud properties are investigated with a high-resolution ensemble (30 members). In the investigated case, moderately deep convection develops along sea-breeze convergence zones over the southwestern peninsula of the UK. A detailed analysis of the mechanism of aerosol cloud interactions in this case has been presented in the first part of this study (Miltenberger et al., 2017). The meteorological ensemble (10 members) varies by about a factor 2 in boundary layer moisture convergence, surface precipitation, and cloud fraction, while aerosol number concentrations are varied by a factor 100 between the three considered aerosol scenarios. If ensemble members are paired according to the meteorological initial and boundary conditions, aerosol-induced changes are consistent across the ensemble. Aerosol-induced changes in CDNC, cloud fraction, cell number and size, outgoing shortwave radiation, instantaneous and mean precipitation rates, and precipitation efficiency are statistically significant at the 5 % level, but changes in cloud top height or condensate gain are not. In contrast, if ensemble members are not paired according to meteorological conditions, aerosol-induced changes are statistically significant only for CDNC, cell number and size, outgoing shortwave radiation, and precipitation efficiency. The significance of aerosol-induced changes depends on the aerosol scenarios compared, i.e. for an increase or decrease relative to the standard scenario. A simple statistical analysis of the results suggests that a large number of realisations (typically > 100) of meteorological conditions within the uncertainty of a single day needs to be consider for retrieving robust aerosol signals in most cloud properties. Only for CDNC and shortwave radiation small samples are sufficient. While the results are strictly only valid for the investigated case, the presented evidence combined with previous studies highlights the necessity for careful consideration of intrinsic predictability, detailed meteorological conditions, and co-variability between aerosol and meteorological conditions for observational or modelling studies of aerosol indirect effects.
- Subjects
CONVECTIVE clouds; ATMOSPHERIC aerosols; ATMOSPHERIC boundary layer; METEOROLOGICAL precipitation; RADIATION
- Publication
Atmospheric Chemistry & Physics Discussions, 2018, p1
- ISSN
1680-7367
- Publication type
Article
- DOI
10.5194/acp-2018-167