Rossby waves, extreme fronts, and wildfires in southeastern Australia

TitleRossby waves, extreme fronts, and wildfires in southeastern Australia
Publication TypeJournal Article
Year of Publication2015
AuthorsReeder M.J, Spengler T., Musgrave R.
JournalGeophysical Research Letters
Date Published2015/03
Type of ArticleArticle
ISBN Number0094-8276
Accession NumberWOS:000353170000051
Keywords2d model; baroclinic instability; black saturday; bushfire; cold fronts; continental boundary-layer; dynamics; fire weather; front; heat; meteorology; Rossby wave; surface; victoria; waves; wildfire

The most catastrophic fires in recent history in southern Australia have been associated with extreme cold fronts. Here an extreme cold front is defined as one for which the maximum temperature at 2m is at least 17 degrees C lower on the day following the front. An anticyclone, which precedes the cold front, directs very dry northerlies or northwesterlies from the interior of the continent across the region. The passage of the cold front is followed by strong southerlies or southwesterlies. European Centre for Medium-Range Weather Forecasts ERA-Interim Reanalyses show that this regional synoptic pattern common to all strong cold fronts, and hence severe fire conditions, is a consequence of propagating Rossby waves, which grow to large amplitude and eventually irreversibly overturn. The process of overturning produces the low-level anticyclone and dry conditions over southern Australia, while simultaneously producing an upper level trough and often precipitation in northeastern Australia.

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