Anti-correlation between stratospheric aerosol extinction and the Angstromparameter from multiple wavelength measurements with SAGE II - a characteristic of the decay period following major volcanic eruptions

Stratospheric Aerosol and Gas Experiment (SAGE) II data at multiple wavelen gths were analyzed to show how aerosol extinction decays with time followin g major volcanic eruptions. Comparisons were made between the lowest backgr ound level in 1999 and the past data record of the stratospheric aerosol la yer. The time variation of the extinction coefficients was compared with th e Angstrom parameter, which is a good indicator of particle size. A clear a nti- correlation was found between the extinction and the Angstrom. paramet er after the eruption of Mt. Pinatubo. Comparison of the extinction coeffic ients and Angstrom parameters in 1989 and 1999 made it clear that the aeros ol layer was affected by volcanic eruptions in 1989. The distinguishing neg ative correlation is a characteristic feature of decay periods following vo lcanic eruptions.