Investigating the Vertical Structure of Volcanic Clouds Using NPP/OMPS Limb Aerosol Observations and the GEOS-5/GOCART Model

Abstract:

The explosive eruption of Chile’s Calbuco volcano on April 22nd-23rd produced large volcanic ash and sulfur dioxide clouds that were observed by satellites for over a week. The volcanic clouds were reported to have spanned a large range of altitudes, from 12 km to greater than 20 km. This is confirmed by the vertical profiles of aerosols observed by the NPP/OMPS Limb Profiler, which have a frequency and sensitivity allowing for a thorough look into the evolving vertical structure of the volcanic clouds. The volcanic cloud aerosol signature in the OMPS Limb profiles can be better understood by comparing them to simulations of the volcanic sulfate aerosols, and volcanic ash of various particle sizes.

 UV and IR satellite observations from the first few days of the eruption are used to constrain the initial source parameters that describe the volcanic eruption (eruption time, duration, mass emitted, injection altitude). The GEOS-5/GOCART model uses these initial source parameters to simulate the transport, deposition, and chemical conversion processes within the volcanic clouds. OMPS limb observations taken during the first days after the eruption provide numerous detailed vertical profiles of the volcanic clouds. The OMPS Limb Aerosol Scattering Index profiles are compared to the GEOS-5/GOCART simulations of sulfate aerosols and volcanic ash to show: the complex vertical structure of the volcanic plumes, the extended presence of aerosols in the volcanic clouds well after the eruption, and how OMPS Limb profiles can be used to constrain different volcanic aerosols in the GEOS-5/GOCART model simulations.