Radiatively forced dispersion of the Mt. Pinatubo volcanic cloud and induced temperature perturbations in the stratosphere during the first few months following the eruption

Abstract

A combined 3‐dimensional circulation model and aerosol microphysical/transport model is used to simulate the dispersion of the Mt. Pinatubo volcanic cloud in the stratosphere for the first few months following the eruption. Radiative heating of the cloud due to upwelling infrared radiation from the troposphere is shown to be an important factor affecting the transport. Without cloud heating, cloud material stays mostly north of the equator, whereas with cloud heating, the cloud is transported southward across the equator within the first two weeks following the eruption. Generally the simulations agree with TOMS, AVHRR, and SAGE satellite observations showing the latitude distribution of cloud material to be between about 20°S and 30°N within the first few months. Temperature perturbations in the stratosphere induced by the aerosol heating are generally 1–4 K, in the range of those observed.