Modes of climate variability and heat waves in Victoria, southeastern Australia

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Abstract

Summertime heat waves in the southeastern state of Victoria, Australia, are associated with broad anticyclonic upper level potential vorticity (PV) anomalies. The current research establishes the relationship between heat waves, precipitation, and three modes of climate variability of importance for rainfall in Australia: the El Niño-Southern Oscillation (ENSO), Madden-Julian Oscillation (MJO), and Southern Annular Mode (SAM). Heat waves in Victoria in summer are more common during phases 3-6 of the MJO (when convection is enhanced over the eastern Indian Ocean, Maritime Continent, and western Pacific Ocean) and La Niña phases of ENSO. The PV-Theta (Θ) structure of the heat wave and pattern of convection varies with the phase of each mode of variability. Enhanced tropical convection results in a heat wave characterized by a monopole of anticyclonic PV, whereas suppressed convection is associated with a dipole of anticyclonic and cyclonic PV. Key Points Heat waves are more common in La Niña phases of ENSO and phases 3-6 of the MJOThe PV-Theta and convection patterns vary with the phase of each mode

Original languageEnglish
Pages (from-to)6926-6934
Number of pages9
JournalGeophysical Research Letters
Volume41
Issue number19
DOIs
Publication statusPublished - 16 Oct 2014

Keywords

  • ENSO
  • heat waves
  • MJO
  • SAM

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