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

2. Laboratory Experiments A. Cloud types Layer upslope stratus Wave Cumulus warm base cold base

3. Laboratory Experiments B. Discussion Topics-AIDA desert dust PaulF summarized yesterday Sulfuric acid coated soot aerosols new JGR paper, in press

4. AIDA (Aerosol Interactions and Dynamics in the Atmosphere) 84 m 3

5. AIDA - Sulfuric acid coated soot aerosols ice 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), 611–614. Koop w. sat

6. Lab (& modeling) studies DescriptionMeasurementsVariables water cloud formation rh > 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 < 100% same, plus ice crystals artificial CCN properties (ammonium sulfate, sulfuric acid, sodium chloride,..) Heterog. freezing rh < 100% same, + IN activation spectra (T, rh) (1) Externally mixed aerosol: artificial CCN & IN; aerosol chemistry (2) Internally mixed aerosol Heterog. freezing rh > 100% samesame - (how important is the presence of the liquid phase?) laboratory-generated surrogates of naturally particles: sea-salt; mineral dust; soot natural air rh 100% samenatural air entrainment-mixingsameAerosol size, chem, elec charge,..

7. Measurement challenges Ice nucleation modes: deposition …………………………. X condensation-freezing …………..X contact-freezing …………………X 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)

8. 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

10. Fluid dynamics modeling of instruments

11. Computational mesh at inlet

12. Compare FLUENT vs approx. thermodynamic trajectories

13. Compare FLUENT vs approx. velocity profile