What do we need to know to model the microphysical evolution of volcanic clouds and how can we make these measurements?

Jason M English, NOAA GSL, Boulder, CO, United States; University of Colorado at Boulder, Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, Owen B Toon, LASP/ATOC, Boulder, CO, United States; University of Colorado at Boulder, Boulder, CO, United States and Michael J Mills, National Center for Atmospheric Research, Atmospheric Chemistry, Observations, and Modeling Laboratory, Boulder, CO, United States