Role of quasiresonant planetary wave dynamics in recent boreal spring-to-autumn extreme events.
In boreal spring-to-autumn (May-to-September) 2012 and 2013, the Northern Hemisphere (NH) has experienced a large number of severe midlatitude regional weather extremes. Here we show that a considerable part of these extremes were accompanied by highly magnified quasistationary midlatitude planetary waves with zonal wave numbers m = 6, 7, and 8. We further show that resonance conditions for these planetary waves were, in many cases, present before the onset of high-amplitude wave events, with a lead time up to 2 wk, suggesting that quasiresonant amplification (QRA) of these waves had occurred. Our results support earlier findings of an important role of the QRA mechanism in amplifying planetary waves, favoring recent NH weather extremes.
Potsdam Institute for Climate Impact Research, D-14412 Potsdam, Germany; john@pik-potsdam.de petukhov@pik-potsdam.de.
Vladimir
V
Petoukhov
Potsdam Institute for Climate Impact Research, D-14412 Potsdam, Germany;
Stefan
S
Petri
Potsdam Institute for Climate Impact Research, D-14412 Potsdam, Germany;
Stefan
S
Rahmstorf
Potsdam Institute for Climate Impact Research, D-14412 Potsdam, Germany;
Dim
D
Coumou
Potsdam Institute for Climate Impact Research, D-14412 Potsdam, Germany;
Kai
K
Kornhuber
Potsdam Institute for Climate Impact Research, D-14412 Potsdam, Germany; Santa Fe Institute, Santa Fe, NM 87501 john@pik-potsdam.de petukhov@pik-potsdam.de.
Hans Joachim
HJ
Schellnhuber
atmospheric dynamics; heat waves; planetary waves; waveguides; weather extremes