This award is for support for a study to sample surface snow in pits and to drill shallow cores in the vicinity of South Pole to look for evidence of the June, 1991, eruption of Mt. Pinatubo in the Philippines. Extensive measurements and observations by satellite, ground-based and airborne atmospheric instruments are available regarding the amount of sulfur dioxide emitted from the eruption, as well as the global distribution and decay of the stratospheric aerosols derived from the volcanic sulfur dioxide. Ground-based and airborne measurements in Antarctica clearly indicate that the stratospheric sulfate aerosols from this eruption reached high southern latitudes in late 1991 and persisted in the Antarctic atmosphere through 1993. Preliminary results from snow pit samples recently taken in the South Pole area indicate that the Pinatubo signal exists and can be separated from the signal of another volcanic eruption (Cerro Hudson) which occurred in mid-August, 1991. Combined with the known total sulfate aerosol production from Pinatubo, the proposed sampling and analyses will yield the quantitative information necessary to establish empirical relationships between the explosivity of a low-latitude eruption and the amplitude of its corresponding signals in Antarctic snow.
