Cloud Chemistry

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Cloud Chemistry
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STERAO/Deep Convection 1996
NO, NO2, HNO3 HOx OH HO2 HOx
precursors H2O2, CH2O, CH3OOH Also SO2, SO4
July 10, 1996 Storm From Dye et al. (2000)
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Aqueous-Phase Chemical Reactions

• NO, NO2 insoluble
• Nitric Acid HNO3 highly soluble
• Aq. Rxns minimal
• Hydrogen Peroxide H2O2 highly soluble
• SO2 destroys H2O2 , but HO2 O2- produces H2O2
• Formaldehyde CH2O highly soluble
• Oxidation by OH destroys CH2O
• Frieds measurements often show a CH2O increase
  downwind of convection
• Methyl Hydrogen Peroxide CH3OOH moderately
  soluble
• Oxidation by OH destroys CH3OOH
• Sulfur Dioxide SO2 highly soluble
• Oxidation by H2O2 and O3 destroys SO2

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Transects across Anvil
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Processes in deep convection that affect chemical
species

• Phase of cloud particles
• cloud microphysics and chemical species

washout and rainout
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Needed Measurements
NO, HNO3, OH, HO2, H2O2, CH3OOH, CH2O, SO2 in
outflow
Hydrometeor structure of storm
Whats on/in the ice?
NO, HNO3, OH, HO2, H2O2, CH3OOH, CH2O, SO2 in
inflow
pH, ions, and liquid phase species in
precipitation