Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling

Amplification of Waveguide Teleconnections in the Boreal Summer

TitleAmplification of Waveguide Teleconnections in the Boreal Summer
Publication TypeJournal Article
Year of Publication2019
JournalCurrent Climate Change Reports
Volume5
Number4
Pages421-432
Abstract / Summary

Purpose of Review: While the influence of climate change on mid-latitude atmospheric circulation remains uncertain, hypotheses based on linear waveguide dynamics have been proposed suggesting amplification of circumglobal quasi-stationary Rossby wave events, which may have led to persistent and high-impact extremes in recent boreal summers. It is thus useful to synthesize these hypotheses and to discuss limitations of this simplified dynamical framework for explaining observed features.

Recent Findings: The hypothesis that climate change can alter the basic circulation state and thereby enhance circumglobal waveguide teleconnections by increasing their resonance has been proposed but has not yet been verified with models. Furthermore, there is no convincing evidence that the variability of disturbances within the waveguide will increase in future climates projected by the CMIP5 models. On the other hand, recent research indicates that enhanced diabatic heating, particularly that associated with increasing aridity in the mid-latitude, can stimulate the jet stream waveguides, thus suggesting an alternative mechanism which, if properly modeled, could lead to more high-amplitude circumglobal planetary wave events.

Summary: There could be circumstances that lead to resonant amplification of waveguide Rossby waves in the boreal summer, but an alternative mechanism that involves changes in the forcing rather than the mean state deserves closer attention.

URLhttp://dx.doi.org/10.1007/s40641-019-00150-x
DOI10.1007/s40641-019-00150-x
Journal: Current Climate Change Reports
Year of Publication: 2019
Volume: 5
Number: 4
Pages: 421-432
Publication Date: 12/2019

Purpose of Review: While the influence of climate change on mid-latitude atmospheric circulation remains uncertain, hypotheses based on linear waveguide dynamics have been proposed suggesting amplification of circumglobal quasi-stationary Rossby wave events, which may have led to persistent and high-impact extremes in recent boreal summers. It is thus useful to synthesize these hypotheses and to discuss limitations of this simplified dynamical framework for explaining observed features.

Recent Findings: The hypothesis that climate change can alter the basic circulation state and thereby enhance circumglobal waveguide teleconnections by increasing their resonance has been proposed but has not yet been verified with models. Furthermore, there is no convincing evidence that the variability of disturbances within the waveguide will increase in future climates projected by the CMIP5 models. On the other hand, recent research indicates that enhanced diabatic heating, particularly that associated with increasing aridity in the mid-latitude, can stimulate the jet stream waveguides, thus suggesting an alternative mechanism which, if properly modeled, could lead to more high-amplitude circumglobal planetary wave events.

Summary: There could be circumstances that lead to resonant amplification of waveguide Rossby waves in the boreal summer, but an alternative mechanism that involves changes in the forcing rather than the mean state deserves closer attention.

DOI: 10.1007/s40641-019-00150-x
Citation:
Teng, H, and G Branstator.  2019.  "Amplification of Waveguide Teleconnections in the Boreal Summer."  Current Climate Change Reports 5(4): 421-432.  https://doi.org/10.1007/s40641-019-00150-x.