Presented by Ulrike Neimeier and Stefan Lorenz from the Max-Planck Institute for Meteorology in Hamburg, Germany.
Wednesday, April 21, 4:00 pm
Room 1200, IPAM (Portola Plaza Building)
The current eruption of the Eyafjallajoekull in Iceland has caused enormous chaos at European airports as sharp glass particles of varying diameter contained in volcanic ash plumes can be very dangerous for airplane jet engines. Ash plumes are emitted by volcanoes into the upper troposphere and the stratosphere. They are transported and distributed through strong jet streams around the globe. Volcanoes do not only emit ash, but also large amounts of SO2 which converts to sulfate aerosol. The lifetime of the emitted volcanic aerosol varies between a few weeks for fine ash and several years for sulfate in the stratosphere. Stratospheric sulfate can influence earth climate severely via radiative processes.
In this talk, we will present a two step modeling approach. The interactive simulation of formation, dispersal and temporal development of a very large volcanic cloud is performed with the middle atmosphere general circulation model including a global aerosol module, based on ECHAM5. The first part of the talk focuses on the evolution of a volcanic aerosol cloud originating from assumed Mt. Pinatubo and Yellowstone eruptions. The second part is concerned with long-term climatic effects of large eruptions during the last Millennium. Changes of temperature and dynamics of the carbon cycle, simulated with the earth system model version of ECHAM5, will be discussed.