Quasi-Resonant Amplification, Arctic De-amplification, and Projected Changes in Persistent Extreme Warm-Season Weather Events
Abstract
Persistent episodes of extreme weather in the Northern Hemisphere summer have been associated with high-amplitude quasi-stationary atmospheric Rossby waves with zonal wavenumbers 6-8 resulting from the phenomenon of Quasi-Resonant Amplification (QRA).A fingerprint for the occurrence of QRA can be defined in terms of the zonally-averaged surface temperature field. Examining state-of-the-art (CMIP5) climate model projections we find that QRA events are likely to increase by 50% this century under business-as-usual carbon emissions, but there is considerable variation among climate models. Some predict a near tripling of QRA events by the end of the century, while others predict a potential decrease. Models with amplified Arctic warming yield the most pronounced increase in QRA events. The projections are strongly dependent on assumptions regarding the nature of changes in radiative forcing associated with anthropogenic aerosols over the next century. One implication of our findings is that a reduction in mid-latitude aerosol loading could actually lead to Arctic de-amplification this century, ameliorating potential increases in persistent extreme weather events.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMGC11B..03M
- Keywords:
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- 1616 Climate variability;
- GLOBAL CHANGEDE: 1620 Climate dynamics;
- GLOBAL CHANGEDE: 1630 Impacts of global change;
- GLOBAL CHANGEDE: 4313 Extreme events;
- NATURAL HAZARDS