Heatwave Location Changes in Relation to Rossby Wave Phase Speed

Wolfgang Wicker, Nili Harnik, Maria Pyrina, Daniela I.V. Domeisen

Research output: Contribution to journalArticlepeer-review

Abstract

Surface anticyclones connected to the ridge of an upper-tropospheric Rossby wave are the main dynamical drivers of mid-latitude summer heatwaves. It is, however, unclear to what extent an anomalously low zonal phase speed of the wave in the upper troposphere is necessary for persistent temperature extremes at the surface. Here, we use spectral decomposition to separate fast and slow synoptic-scale waves. A composite analysis of ERA5 reanalysis data reveals that, while in some regions heatwaves become more frequent during episodes of weak or no phase propagation, temperature extremes in other regions are commonly associated with more rapidly eastward propagating Rossby waves. Reflected in the mean heatwave duration as well, this relationship is possibly linked to a longitudinal phase preference of slow and fast waves or a meridional storm track shift. These findings open up new questions about the influence of mid-latitude dynamics on temperature extremes.

Original languageEnglish
Article numbere2024GL108159
JournalGeophysical Research Letters
Volume51
Issue number14
DOIs
StatePublished - 28 Jul 2024

Keywords

  • heatwaves
  • phase speed
  • Rossby waves
  • synoptic-scale

All Science Journal Classification (ASJC) codes

  • Geophysics
  • General Earth and Planetary Sciences

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