THE POLEWARD DISPERSAL OF MOUNT-PINATUBO VOLCANIC AEROSOL

Using the SAGE II 1-mum stratospheric aerosol extinction ratio observations. the dispersal of Mount Pinatubo aerosol within two transport regimes during the first 10 months after the eruption is displayed in meridional cross sections. Maximum aerosol extinction ratio values were contained in a tropical reservoir bounded by strong gradients in the subtropics. The detainment of aerosol from the equatorial reservoir occurred in episodic synoptic scale events and two examples are presented: (1) transport into the boreal summer hemisphere in a lower regime just 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 activity in the southern subtropics.