THE POLEWARD DISPERSAL OF MOUNT-PINATUBO VOLCANIC AEROSOL

Using the SAGE II 1-mum stratospheric aerosol extinction ratio observa tions. the dispersal of Mount Pinatubo aerosol within two transport re gimes during the first 10 months after the eruption is displayed in me ridional cross sections. Maximum aerosol extinction ratio values were contained in a tropical reservoir bounded by strong gradients in the s ubtropics. The detainment of aerosol from the equatorial reservoir occ urred in episodic synoptic scale events and two examples are presented : (1) transport into the boreal summer hemisphere in a lower regime ju st above the tropopause associated with upwardly decaying tropospheric disturbances and (2) dispersal into the austral winter hemisphere in an upper transport regime near 30 hPa associated with planetary wave a ctivity in the southern subtropics.