Perturbation in atmospheric charged species after the eruption of Mount Pinatubo

This paper presents the results of coupled neutral-ion photochemical model to demonstrate that gets-phase sulfur chemistry played a vital role in pert urbations of the stratospheric ion composition following the Pinatubo erupt ion. Model calculations indicate that immediately after the eruption, the l arge amount of SO2 injected directly into the tropical stratosphere produce d additional sulfuric acid vapor which increased the abundance of heavy neg ative ion family (called HSO4- core) by several orders of magnitude over th e ambient. After 2 to 3 months, most of the sulfuric acid vapor gets conden sed and converted to HSO4 / H2O droplets (aerosols) and the density of ultr afine charged aerosol (which are driven by aerosol) also increases several folds (similar to 1500%) in the tropics for 20-30 km. The perturbation in i onic species was evident even after one year of eruption (which attains a g lobal coverage) but it finally settled down to its background level after a bout 2 years.