Perturbation in atmospheric charged species after the eruption of Mount Pinatubo

Abstract

This paper presents the results of coupled neutral-ion photochemical model to demonstrate that gas-phase sulfur chemistry played a vital role in perturbations of the stratospheric ion composition following the Pinatubo eruption. Model calculations indicate that immediately after the eruption, the large amount of SO₂ injected directly into the tropical stratosphere produced additional sulfuric acid vapor which increased the abundance of heavy negative ion family (called HSO₄ - core) by several orders of magnitude over the ambient. After 2 to 3 months, most of the sulfuric acid vapor gets condensed and converted to HSO₄ / H₂O droplets (aerosols) and the density of ultrafine charged aerosol (which are driven by aerosol) also increases several folds (~1500%) in the tropics for 20-30 km. The perturbation in ionic species was evident even after one year of eruption (which attains a global coverage) but it finally settled down to its background level after about 2 years.