Using OMPS-LP Color Ratio to Extract Stratospheric Aerosol Particle Size and Concentration with Application to Volcanic Eruptions

We develop an algorithm that uses the aerosol extinction at two wavelengths (color ratio, 510 nm/869 nm) to derive the size and number density for Ozone Mapping Profiler Suite Limb Profiler (OMPS-LP) stratospheric aerosols. We show uncertainties in size and concentration estimates due to uncertainties in the color ratio, the particle size distributions and the Mie scattering angles. The uncertainty can be quite large, reaching up to 50%, due to the combined systematic effects. Our results compare favorably to balloon borne particle size and concentration measurements between 18 and 24 km. They are also in good agreement with measurements made by the Stratospheric Aerosol and Gas Experiment on the International Space Station (SAGE III/ISS) over multiple scattering angle ranges. We show our estimates of the changes in aerosol size and concentration under ambient conditions and following the Raikoke and Hunga Tonga-Hunga Ha’apai volcanic eruptions.