Journal article
Australian hot and dry extremes induced by weakenings of the stratospheric polar vortex
EP Lim, HH Hendon, G Boschat, D Hudson, DWJ Thompson, AJ Dowdy, JM Arblaster
Nature Geoscience | Published : 2019
Abstract
The occurrence of extreme hot and dry conditions in warm seasons can have large impacts on human health, energy and water supplies, agriculture and wildfires. Australian hot and dry extremes have been known to be associated with the occurrence of El Niño and other variations of tropospheric circulation. Here we identify an additional driver: variability of the stratospheric Antarctic polar vortex. On the basis of statistical analyses using observational data covering the past 40 yr, we show that weakenings and warmings of the stratospheric polar vortex, which episodically occur during austral spring, substantially increase the chances of hot and dry extremes and of associated fire-conducive ..
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Grants
Awarded by Department of Agriculture, Australian Government
Funding Acknowledgements
This study is part of the Forewarned is Forearmed project, which is supported by funding from the Australian Government Department of Agriculture as part of its Rural R&D for Profit programme. G.B. and J.M.A. were supported by the Australian Research Council Centre of Excellence for Climate Extremes (grant CE170100023). J.M.A. was also supported by the Regional and Global Model Analysis component of the Earth and Environmental System Modeling Program of the US Department of Energy's Office of Biological & Environmental Research via National Science Foundation IA 1947282. A.J.D. was supported by funding from the Australian Government's National Environmental Science Program. D.W.J.T. was supported by the NSF Climate and Large-Scale Dynamics Program. We thank T. Cowan and B. Trewin at the Bureau of Meteorology for their constructive feedback on the manuscript. We also thank M. Griffiths at the Bureau of Meteorology for processing AWAP data for the analysis of the study. This research was undertaken at the NCI National Facility in Canberra, Australia, which is supported by the Australian Commonwealth Government. The NCAR Command Language (NCL; http://www.ncl.ucar.edu) version 6.4.0 was used for data analysis and visualization of the results. We also acknowledge NCAR/UCAR, NOAA, ECMWF and the Japanese Met Agent for producing and providing the Hurrell et al. (2008) SST analysis, the Reynolds OI v2 SST analysis, the ERA-Interim reanalysis and the JRA-55 reanalysis, respectively.