ANNUALLY RESOLVED SOUTHERN-HEMISPHERE VOLCANIC HISTORY FROM 2 ANTARCTIC ICE CORES

The continuous sulfate analysis of two Antarctic ice cores, one from t he Antarctic Peninsula region and one from West Antarctica, provides a n annually resolved proxy history of southern semisphere volcanism sin ce early in the 15th century. The dating is accurate within +/-3 years due to the high rate of snow accumulation at both core sites and the small sample sizes used for analysis. The two sulfate records are cons istent with each other. A systematic and objective method of separatin g outstanding sulfate events from the background sulfate flux is propo sed and used to identify all volcanic signals. The resulting volcanic chronology covering 1417-1989 A.D. resolves temporal ambiguities about several recently discovered events. A number of previously unknown, m oderate eruptions during late 1600s are uncovered in this chronology. The eruption of Tambora (1815) and the recently discovered eruption of Kuwae (1453) in the tropical South Pacific injected the greatest amou nt of sulfur dioxide into the southern hemisphere stratosphere during the last half millennium. A technique for comparing the magnitude of v olcanic events preserved within different ice cores is developed using normalized sulfate flux. For the same eruptions the variability of th e volcanic sulfate flux between the cores is within +/- 20% of the sul fate flux from the Tambora eruption.