Observations of boreal forest fire smoke in the stratosphere by POAM III, SAGE II, and lidar in 1998

A substantial increase in stratospheric aerosol was recorded between May and October 1998 between 55 degrees and 70 degrees N. This phenomenon was recorded in the absence of reported volcanic eruptions with stratospheric impact potential. The FOAM III and SAGE II instruments made numerous measurements of layers of enhanced aerosol extinction substantially higher than typical values 3 to 5 km above the tropopause. A comparison of these observations with lidar profiles, TOMS aerosol index data, and forest fire statistics reveals a strong link between stratospheric aerosol and forest fire smoke. Our analysis strongly suggests that smoke from boreal forest fires was lofted across the tropopause in substantial amounts in several episodes occurring in Canada and eastern Russia. Observations reveal a broad zonal increase in stratospheric aerosol that persisted for at least three months.