Analyses suggest that when dust acts as CCN, cloud droplet nucleation and conversion to rain tend to limit the amount of dust that is transported above the freezing level for activation as IN by efficiently removing the dust via nucleation scavenging and precipitation scavenging. In this case, a relatively high concentration of dust acts to suppress the conversion of cloud droplet to rain, leads to production of fewer, but larger rain drops, reduces the magnitude and intensity of rainfall, and produces weaker cold pools. The weaker cold pools allow the leading edge of the outflow boundary to stay closely coupled with the main updraft, thus leading to longer lived storms. When dust behaves solely as IN a large fraction of the dust is transported aloft where it enhances ice nucleation and leads to higher concentrations of smaller cloud ice particles.
These results suggest that dust has the potential to indirectly influence the radiation budget by increasing the longevity of deep convective storms when behaving as CCN or by modifying the cloud ice spectra and cloud top albedo when acting as IN.