How will dust variability change the effect of dust as ice nuclei?

Observation suggest a doubling of dust over much of the globe during the 20th century (Mahowald et al., 2010). Dust emission rate in North Africa in the 1950s was 9 times lower than during 1980-84 (Mukhopadhyay and Kreycik, 2008). We also know that dust is an important ice nuclei. Therefore, it is important to know how the variability of dust could affect the climate through acting as ice nuclei. A state-of-art GCM with double moment cloud microphysics scheme and ice nucleation treatment for dust and black carbon (BC) was employed. We focus on mixed-phase clouds for the simplicity of the study. The effect of BC as ice nuclei is also investigated.