Evidence of transport, sedimentation and coagulation mechanisms in the relaxation of post-volcanic stratospheric aerosols

Spatio-temporal distributions of stratospheric aerosols, measured by the ORA instrument from August 1992 until May 1993, are presented in the latitude range (40◦ S–40◦ N). Particle total number density, mode radius and distribution width are derived and interpreted. The respective roles of advection, sedimentation and coagulation are discussed. We also identify clear transport/sedimentation patterns and we show the enhancement of coagulation in stagnation regions. Efficient transport of aerosol particles up to 50 km is suggested.