Understanding Observed Stratocumulus Variability and Implications for Aerosol Indirect Effects

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Understanding Observed Stratocumulus Variability
and Implications for Aerosol Indirect Effects

• Nathan Johnson

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Outline

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

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Introduction

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

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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)

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MASE
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Data Description
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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
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Principle Components Analysis N0
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EOF N0
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Principle Components Analysis N
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EOF N
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Principle Components Analysis NR2
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EOF NR2
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North Test
Weight Color
N0 Black
N Red
NR2 Green
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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