“…Many components of atmospheric IN have been identified, such as minerals of desert dust, bacteria, pollen and plant debris (Pruppacher and Klett, 1997;Szyrmer and Zawadsky, 1997) although for many of them the concentrations and relevance to cloud processes are still unclear (Möhler et al, 2007;DeMott et al, 2010). In addition to these surface-derived sources, volcanism is debated as a source of atmospheric ice nuclei, with conflicting evidence from field measurements (Isono et al, 1959;Price and Pales, 1963;Hobbs et al, 1971;Schnell and Delany, 1976;Radke et al, 1976). Recent satellite observations (Gasso, 2008) show that natural degassing or weakly explosive volcanoes in the South Atlantic and North Pacific affect low marine stratocumulus for up to 1300 km downwind by decreasing droplet effective radius and increasing visible brightness, and may add cloud cover in otherwise cloudless areas.…”