Investigating multi-decadal scale changes in ENSO variability using a coupled A/OGCM
Abstract
We simulate multi-decadal and multi-centennial ENSO variability using GENMOM, a non flux-corrected A/OGCM comprised of the GENESIS V3.0 atmospheric model and the MOM2 ocean model. The model produces realistic ENSO variability comparable with similar models used in the 2007 IPCC assessment. Long integrations of the model yield significant changes in the frequency and amplitude of ENSO on decadal and centennial time scales. A suite of equilibrium simulations in which atmospheric CO2 levels were prescribed at LGM (180 ppmV), 6Ka (280 ppmV with 6Ka solar forcing), present (355 ppmV), doubled and quadrupled values display differing characteristics of ENSO variability. Wavelet analysis of the present simulation shows significances at both 12 - 30 years multi-decadal range and 70 - 100 year centennial scale range. Initial results show that only slight changes in ENSO variability and amplitude exist between simulations calculated over the entire length of the runs. However, subsampling at decadal and centennial scales shows large changes, indicating a low frequency pattern in the ENSO signal.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMPP43B1519A
- Keywords:
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- 1626 Global climate models (3337;
- 4928);
- 4522 ENSO (4922);
- 4922 El Nino (4522)