ICE - Laboratory experiment goals

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ICE - Laboratory experiment goals

• Basic scientific understanding
• Check performance of airborne instruments
• Develop new measurement techniques combining
  methods (CVI -gt CFDC)
• STRENGTHS
• Environment control
• Repeatability
• Mechanistic studies
• Test specific aerosol types (dust, bacteria, ..)
• Crystal growth habits rates
• Effects of organic coatings, electric charge, ..

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Laboratory Experiments A. Cloud types

• Layer
• upslope
• stratus
• Wave
• Cumulus
• warm base
• cold base

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Laboratory Experiments B. Discussion Topics-AIDA

• desert dustPaulF summarized yesterday
• Sulfuric acid coated soot aerosolsnew JGR paper,
  in press

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AIDA (Aerosol Interactions and Dynamics in the
Atmosphere)
84 m3
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AIDA - Sulfuric acid coated soot aerosolsice
nucleating threshold
Koop, T., B. P. Luo, A. Tsias, and T. Peter
(2000), Water activity as the determinant for
homogeneous ice nucleation in aqueous solutions,
Nature, 406 (6796), 611614.
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Lab ( modeling) studies
Description Measurements Variables
water cloud formation rh gt 100 CCN spectra, haze cloud drop conc, particle sizes (1) CCN chemistry, sizes conc, LCL, updraft (2) internally mixed or externally mixed aerosol organic films
Homog. freezing rh lt 100 same, plus ice crystals artificial CCN properties (ammonium sulfate, sulfuric acid, sodium chloride, ..)
Heterog. freezing rh lt 100 same, IN activation spectra (T, rh) (1) Externally mixed aerosol artificial CCN IN aerosol chemistry (2) Internally mixed aerosol
Heterog. freezing rh gt 100 same same - (how important is the presence of the liquid phase?) laboratory-generated surrogates of naturally particles sea-salt mineral dust soot
natural airrh lt 100 rh gt 100 same natural air
entrainment-mixing same Aerosol size, chem, elec charge, ..
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Measurement challenges

• Ice nucleation modes
• deposition .X
• condensation-freezing..X
• contact-freezingX
• evaporation-freezing ?
• electro-freezing?
• Discriminating liquid from ice at small sizes (1
  µm)
• Development of new techniques to measure ice
  nuclei
• Aerosol concentrator (to improve statistics)

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Lab studies possible participants

• NCAR
• EOL, ACD
• NOAA
• Aeronomy Lab, ..
• International collaborations
• Germany, Japan, UK, Switzerland

• U.S. universities
• CSU
• DRI
• Michigan Tech.
• South Dakota SMT
• PennState
• Washington
• Colorado
• Wyoming

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Fluid dynamics modeling of instruments
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Computational mesh at inlet
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Compare FLUENT vs approx.thermodynamic
trajectories
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Compare FLUENT vs approx.velocity profile