HR: 0800h
AN: A21E-0789    [Abstracts]
TI: Effects of volcanic eruptions on temperatures near the tropical tropopause: A model-data comparison
AU: * Free, M
EM: melissa.free@noaa.gov
AF: NOAA Air Resources Laboratory, 1315 East West Highway, Silver Spring, MD 20910,
AB: Although the volcanic eruption of El Chichon produced a clear warming at the tropical tropopause, there is a surprising lack of warming after the Pinatubo eruption in both radiosonde and reanalysis data. Here we compare the response at 100 mb in the tropics in radiosonde data to the response in 20th century runs from six models in the AR4 model archive. The models all show substantial warming after Pinatubo, similar to that shown in models and data after El Chichon. Most models also overestimate the stratospheric warming after Pinatubo, but even those that underestimate the response at 50 mb show significant warming at 100 mb. In the mid-troposphere, the models appear to underestimate the extent of amplification of surface cooling after the eruptions. Possible causes of these differences include changes in ozone and water vapor following the eruption, which were not included in the AR4 model runs, as well as interannual variability from the QBO or ENSO. We investigate the effects of these differences on temperature trends.
DE: 0370 Volcanic effects (8409)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 3337 Global climate models (1626, 4928)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting