Stratospheric Aerosol and Gas Experiment (SAGE) II data at multiple wavelengths were analyzed to show how aerosol extinction decays with time following major volcanic eruptions. Comparisons were made between the lowest background level in 1999 and the past data record of the stratospheric aerosol layer. The time variation of the extinction coefficients was compared with the ¿ngstr¿m parameter, which is a good indicator of particle size. A clear anti-correlation was found between the extinction and the ¿ngstr¿m parameter after the eruption of Mr. Pinatubo. Comparison of the extinction coefficients and ¿ngstr¿m parameters in 1989 and 1999 made it clear that the aerosol layer was affected by volcanic eruptions in 1989. The distinguishing negative correlation is a characteristic feature of decay periods following volcanic eruptions. ¿ 2001 American Geophysical Union