Statistically analyzing indirect effects of increased SO2 Low Level Maritime Clouds using A-Train Satellite Observations

Wednesday, 17 December 2014
Adam C Abernathy, University of Utah, Salt Lake City, UT, United States and Gerald G Mace, Univ Utah, Salt Lake City, UT, United States
Mt. Kilauea, located in the Hawaiian Islands, has been actively emitting substantial quantities of SO2 for the past several years. This event provides an excellent experimental case for investigating indirect aerosol effects. This project examines CloudSat reflectivity and MODIS reflectance at the 0.55 and 2.1 micron channels using data from 2006 until 2013. Validation of the volcano’s plume activity and SO2 emissions were conducted using Aura’s OMI retrieval. If the aerosol indirect effects are operable, We expect to find that as SO2 aerosols increase the integrated column radar reflectivity will decrease. It can also be assumed that there will be an increase in 2.1 micron reflectance returns. This signal should be stronger at the plume’s location and is expected to dissipate as the tropical circulation carries the aerosol-loaded clouds westward. While large-scale meteorology events could be a factor in the cloud's aerosol optical depth (AOD), a stronger reflectance would indicate a thicker AOD, which could be attributed to increased SO2 aerosol content. However, this increase in SO2 would limit the liquid water content of these low level clouds thus resulting in reduced precipitation events. However it will be interesting to determine whether as the perturbed air masses reach some sort of equilibrium with the large scale dynamics downstream of the volcanoes if the indirect effects will be distinguishable from the background cloud conditions.