Mass-Independent Sulfur Isotopic Compositions in Stratospheric Volcanic Eruptions
Abstract
The observed mass-independent sulfur isotopic composition (33S) of volcanic sulfate from the Agung (March 1963) and Pinatubo (June 1991) eruptions recorded in the Antarctic snow provides a mechanism for documenting stratospheric events. The sign of 33S changes over time from an initial positive component to a negative value. 33S is created during photochemical oxidation of sulfur dioxide to sulfuric acid on a monthly time scale, which indicates a fast process. The reproducibility of the results reveals that 33S is a reliable tracer to chemically identify atmospheric processes involved during stratospheric volcanism.