Albrecht effect aka the second aerosol indirect effect

18 Pages·2015·2.67 MB·English

Albrecht effect 
a.k.a. the second aerosol indirect effect

Differences in 
precipitation 
“efficiency” between 
continental and marine 
clouds
Battan, L. J., and R. R. Braham, 1956: A Study of Convective Precipitation Based on Cloud and Radar Observations. J. Meteorol.,13, 587–91
Squires, P., 1958: The Microstructure and Colloidal Stability of Warm Clouds. Tellus, 10, 262–71.
Hudson, J. G., 1983: Effects of CCN Concentrations on Stratus Clouds. J. Atmos. Sci., 40, 480–86.
Hocking size 
limit
Later calculations 
for collision 
efficiency of small 
drops
• Sharp drop‐off in collision 
efficiency when small drop 
radius r < 8 m (the 
Hocking limit)
A Short Course in Cloud Physics, Third Edition (International Series in Natural Philosophy), M K Yau, R R Rogers
Albrecht “effect”
• Mentions effect of drizzle on stabilizing PBL
• Model: Albrecht trade‐Cu model, modified to include precip. Models cloud 
fractional cover using an RH‐based parameterization.
Key processes controlling PBL clouds
Radiative (left) and latent (right) heating rates
Informed by 
aircraft 
observations
From Brost, R. A., J. C. Wyngaard, and D. H. Lenschow, 1982: Marine Stratocumulus Layers. Part II: Turbulence Budgets.
J. Atmos. Sci., 39, 818–36.
Also…Nicholls, S., and J. Leighton., 1986: An Observational Study of the Structure of Stratiform Cloud Sheets: Part I.
Structure. Quart. J. Roy. Meteorol. Soc., 112, 431–60.