Editing Rossby wave (section)

== Amplification of Rossby waves ==
{{Anchor|Planetary wave resonance|Planetary wave quasiresonance|Quasiresonant amplification}}
It has been proposed that a number of regional weather extremes in the Northern Hemisphere associated with blocked atmospheric circulation patterns may have been caused by '''quasiresonant amplification of Rossby waves'''. Examples include the [[2013 European floods]], the [[2012 China floods]], the [[2010 Russian heat wave]], the [[2010 Pakistan floods]] and the [[2003 European heat wave]]. Even taking [[global warming]] into account, the 2003 heat wave would have been highly unlikely without such a mechanism.

Normally freely travelling [[synoptic scale meteorology|synoptic]]-scale Rossby waves and [[quasistationary]] planetary-scale Rossby waves exist in the [[mid-latitudes]] with only weak interactions. The hypothesis, proposed by [[Vladimir Petoukhov]], [[Stefan Rahmstorf]], [[Stefan Petri]], and [[Hans Joachim Schellnhuber]], is that under some circumstances these waves interact to produce the static pattern. For this to happen, they suggest, the [[zonal (Earth sciences)|zonal]] (east-west) [[wave number]] of both types of wave should be in the range 6–8, the synoptic waves should be arrested within the [[troposphere]] (so that energy does not escape to the [[stratosphere]]) and mid-latitude [[waveguides]] should trap the quasistationary components of the synoptic waves. In this case the planetary-scale waves may respond unusually strongly to [[orography]] and thermal sources and sinks because of "quasiresonance".<ref>{{cite journal |last1=Petoukhov |first1=Vladimir |last2=Rahmstorf |first2=Stefan |last3=Petri |first3=Stefan |last4=Schellnhuber |first4=Hans Joachim |title=Quasiresonant amplification of planetary waves and recent Northern Hemisphere weather extremes |journal=Proceedings of the National Academy of Sciences of the United States of America |date=2 April 2013 |volume=110 |issue=14 |pages=5336–5341 |doi=10.1073/pnas.1222000110 |pmid=23457264 |pmc=3619331 |bibcode=2013PNAS..110.5336P |doi-access=free }}</ref>

A 2017 study by [[Michael E. Mann|Mann]], Rahmstorf, et al. connected the phenomenon of anthropogenic [[Arctic amplification]] to planetary wave resonance and [[extreme weather]] events.<ref>{{cite journal |last1=Mann |first1=Michael E. |last2=Rahmstorf |first2=Stefan |last3=Kornhuber |first3=Kai |last4=Steinman |first4=Byron A. |last5=Miller |first5=Sonya K. |last6=Coumou |first6=Dim |title=Influence of Anthropogenic Climate Change on Planetary Wave Resonance and Extreme Weather Events |journal=Scientific Reports |date=30 May 2017 |volume=7 |issue=1 |pages=45242 |doi=10.1038/srep45242 |pmid=28345645 |pmc=5366916 |bibcode=2017NatSR...745242M }}</ref>