The ENSO Response to Climate Change in CMIP5
Abstract
Changes to the El Nino/Southern Oscillation (ENSO) and its atmospheric teleconnections under climate change are investigated using simulations conducted for the Coupled Model Intercomparison Project (CMIP5). The overall response to CO2 increases is determined using 27 models, and the ENSO amplitude change based on the multi-model mean is indistinguishable from zero. However, changes between ensembles run with a given model are sometimes significant: for four of the eleven models having ensemble sizes larger than three, the 21st century change to ENSO amplitude is statistically significant. In these four models, ocean vertical stratification is less (more) sensitive to CO2 in models where ENSO strengthens (weakens), likely due to a regulation of the subsurface temperature structure by ENSO-related poleward heat transport. Atmospheric teleconnections also show differences between models where ENSO amplitude does and does not respond to climate change; in the former case El Nino/La Nina-related sea level pressure anomalies strengthen with CO2, and in the latter they weaken and shift polewards and eastwards. Implications for future multi-model studies of the ENSO response to climate change are discussed.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMOS53B1977S
- Keywords:
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- 1616 GLOBAL CHANGE / Climate variability;
- 1626 GLOBAL CHANGE / Global climate models;
- 1635 GLOBAL CHANGE / Oceans;
- 4522 OCEANOGRAPHY: PHYSICAL / ENSO