Understanding Observed Stratocumulus Variability and Implications for Aerosol Indirect Effects Nathan Johnson

Outline Effects of aerosols on Climate Susceptibility Observations of Microphysical Quantities MArine Stratocumulus Experiment Principle Components Analysis

Introduction Indirect Effects of Aerosols on Climate Twomey / Albrecht / Dispersion

Observational effect of N on k k increases with increasing N Pruppacher and Klett (1997) Miles et al. (2000) ??? Yum and Hudson (1997) Lu and Seinfeld (2006) (Modeling) Feingold et al. (1997) (Modeling) Lu et al. (2007) k decreases with increasing N Martin et al. (1994) Ackerman et al. (2000) McFarquhar and Heymsfield (2001) ??? Liu and Daum (2000, 2002) Peng and Lohmann (2003) (Sensitivity)

MASE N L k

Data Description

Principle Components Analysis % Variance Explained by Mode: 1 2 3 CDNC 0.746 0.226 0.028 LWC 0.879 0.001 0.120 k 0.767 0.191 0.042

Principle Components Analysis: N0

EOF: N0

Principle Components Analysis: N

EOF: N

Principle Components Analysis: NR2

EOF: NR2

North Test Weight Color N0 Black N Red NR2 Green

Summary Weighting of the data can influence the result obtained from PCA Scattering - QNR2 Uncertain which method will yield most interesting results Important implications for aerosol indirect effects