HR: 15:10h
AN: A43D-08 INVITED     [Abstracts]
TI: Interactions Between Volcanic Eruptions and El Nino Studies with a Coupled Atmosphere- Ocean Model
AU: * Timmreck, C
EM: claudia.timmreck@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Thomas, M
EM: manu.thomas@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Esch, M
EM: monika.esch@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Giorgtta, M
EM: marco.giogetta@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Graf, H
EM: hfg21@cam.ac.uk
AF: Centre of Atmospheric Sciences University Cambridge, Downing Place, Cambridge, CB2 3EN, United Kingdom
AU: Haak, H
EM: helmuth.haak@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Jungclaus, J
EM: johann.jungclaus@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Mueller, W
EM: wolfgang.mueller@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Roeckner, E
EM: erich.roeckner@zmaw.de
AF: Max Planck Institute for Meteorology, Bundesstr. 53, Hamburg, D-20146, Germany
AU: Stenchikov, G
EM: gera@envsci.rutgers.edu
AF: Rutgers-The State University of NJ, 14 College Farm Rd, New Brunswick, NJ 08901-8551, United States
AB: Major volcanic eruptions have a significant impact on stratospheric and tropospheric climate, atmospheric composition and circulation. After large tropical eruptions observations and subsequent years model simulations show abnormally warm winters over the Northern Hemisphere continents in years following the eruption. During the winters following the three biggest eruptions in the last decades (Agung, El Chichon and Pinatubo) El Ninos took place. It is currently uncertain to what degree ENSO influences the atmospheric response to volcanic forcing and or in which way a volcanic eruption influences the strength and the timing of an El Nino event. Fully coupled Atmosphere-Ocean GCMs are therefore an important tool to improve our current understanding of the atmosphere and ocean response to the combined effects of El Nino and large tropical volcanic eruptions. We have carried out a series of Pinatubo experiments with the coupled atmosphere ocean circulation model, the ECHAM5/MPIOM . The volcanic radiative forcing is calculated online in the model using a realistic spatial- temporal distribution of aerosol optical parameters derived from satellite observations. We present results of at least five ensembles of simulations when the volcanic eruption appears for different states of ENSO: before the onset and during an El Nino event, during a La Nina episode and for a climatological mean. Each ensemble run has been performed for two years. The discussion includes the changes in atmospheric and ocean circulation and in planetary wave propagation. Special emphasis will be placed on the circulation changes in Northern Hemisphere winter.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 4522 ENSO (4922)
DE: 8408 Volcano/climate interactions (1605, 3309)
DE: 8409 Atmospheric effects (0370)
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly