M-PACE Measurements of IN are consistent with long-lived nature of clouds Binned data from 60 s averages over entire project

[IN] variability and dependence on supersaturation in mixed-phase regime measured at altitude for different locales Relevance: Mixed phase clouds

Ice nucleation by coated dusts amenable to parameteric/threotical treatments Classical theory applied to iron oxide/H 2 SO 4 /H 2 O freezing  a w(het) <  a w(hom) Exploited for parameterization by Kärcher and Lohmann (2003, JGR) Water activity based freezing theory applied to heterogeneous freezing Archuleta et al. (2005) Adapted from Zuberi et al. (2002, GRL) Archuleta et al. (2005)

Nucleation rate for iron oxide particles (sizes to 200 nm)

Laboratory natural dust sample comparisions – size and generation method matter Note similarity of behavior to large mineral particles studied by Roberts and Hallett (1968, QJRMS)