Atmospheric and oceanic conditions associated with Southern Australian heat waves: A CMIP5 analysis

Ariaan Purich, Tim Cowan, Wenju Cai, Peter van Rensch, Petteri Uotila, Alexandre Pezza, Ghyslaine Boschat, Sarah Perkins

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25 Citations (Scopus)

Abstract

Atmospheric and oceanic conditions associated with southern Australian heat waves are examined using phase 5 of the Coupled Model Intercomparison Project (CMIP5) models. Accompanying work analyzing modeled heat wave statistics for Australia finds substantial increases in the frequency, duration, and temperature of heat waves by the end of the twenty-first century. This study assesses the ability of CMIP5 models to simulate the synoptic and oceanic conditions associated with southern Australian heat waves, and examines how the classical atmospheric setup associated with heat waves is projected to change in response to mean-state warming. To achieve this, near-surface temperature, mean sea level pressure, and sea surface temperature (SST) from the historical and high-emission simulations are analyzed. CMIP5 models are found to represent the synoptic setup associated with heat waves well, despite showing greater variation in simulating SST anomalies. The models project a weakening of the pressure couplet associated with future outhernAustralian heat waves, suggesting that even a non-classical synoptic setup is able to generatemore frequent heat waves in a warmer world. A future poleward shift and strengthening of heat wave-inducing anticyclones is confirmed using a tracking scheme applied to model projections. Model consensus implies that while anticyclones associated with the hottest future southern Australian heat waves will be more intense and originate farther poleward, a greater proportion of heat waves occur in association with a weaker synoptic setup that, when combined with warmer mean-state temperatures, gives rise to more future heat waves.

Original languageEnglish
Pages (from-to)7807-7829
Number of pages23
JournalJournal of Climate
Volume27
Issue number20
DOIs
Publication statusPublished - 1 Jan 2014
Externally publishedYes

Cite this

Purich, A., Cowan, T., Cai, W., van Rensch, P., Uotila, P., Pezza, A., Boschat, G., & Perkins, S. (2014). Atmospheric and oceanic conditions associated with Southern Australian heat waves: A CMIP5 analysis. Journal of Climate, 27(20), 7807-7829. https://doi.org/10.1175/JCLI-D-14-00098.1