North Atlantic decadal variability: climatic impacts, mechanisms, and predictability
Abstract
The North Atlantic Ocean is characterized by a large-scale pattern of sea surface temperature anomalies that varies on multidecadal time scales, oftentimes called the Atlantic Multidecadal Oscillation (AMO) or Atlantic Multidecadal Variability (AMV). Numerous studies have shown that this observed pattern of decadal variations has a large impact on many aspects of climate, including Atlantic hurricane activity, European and North American summer climate, African monsoon rainfall, and Arctic sea ice. There has been considerable debate on the mechanisms responsible for the AMO, and the relative roles of ocean dynamics, surface flux forcing, and anthropogenic radiative forcing. Here we review recent work in this area, and attempt to provide some synthesis. There appears to be compelling evidence for a major role for ocean dynamics in generating the extratropical part of the AMO. The relatively long time scales associated with ocean dynamics appear to provide some of the basis for skillful decadal predictions of the North Atlantic. However, in the subtropical North Atlantic it appears that surface fluxes play a very significant role in directly driving SST variability through mixed layer processes, with the potential for a significant impact from radiative forcing changes. We discuss potential future work and associated challenges that could help to sharpen our understanding of the mechanisms of Atlantic decadal variability that may improve both our predictive skill on multi-annual to decadal scales and our ability to project future changes in the Atlantic in response to increasing greenhouse gases and changing aerosols.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A31C..01D
- Keywords:
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- 0399 General or miscellaneous;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3399 General or miscellaneous;
- ATMOSPHERIC PROCESSES