caa a22 4500 60547348X CHVBK 20210128100343.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s00382-014-2214-5 doi (NATIONALLICENCE)springer-10.1007/s00382-014-2214-5 Large scale and sub-regional connections in the lead up to summer heat wave and extreme rainfall events in eastern Australia [Elektronische Daten] [Ghyslaine Boschat, Alexandre Pezza, Ian Simmonds, Sarah Perkins, Tim Cowan, Ariaan Purich] Australia has been exposed to a vast array of extreme weather regimes over the past few years, and the frequency and intensity of these events are expected to increase as a result of anthropogenic climate change. However, the predictability of extreme droughts, heat waves (HWs), bushfires and floods, is still hampered by our inability to fully understand how these weather systems interact with each other and with the climate system. This study brings new insight into the regional and large scale dynamics of some extreme events in Australia, by describing and comparing the climate signature of summer HWs and extreme rainfall events which have occurred in the states of Victoria and Queensland respectively, during 1979-2013. Our analyses highlight the importance of mid-latitude dynamics operating during HWs, in contrast with more tropical interactions at play during extreme rainfall events. A ‘common' blocking high pressure system is observed over the Tasman Sea during the two types of extreme events, and may explain why some southeastern HWs (only about 25%) occur in close succession with floods in Queensland. However, our results suggest that there is no dynamical link between these two types of events, since the HW-related anticyclone evolves as part of a baroclinic wave train, whereas in the case of rainfall events, this structure emerges as an equivalent barotropic response to tropical convection. Sub-regional surface temperatures and air-sea fluxes also suggest that distinct processes may be operating in the lead up to these two events. Indeed, HWs tend to occur when the wave train propagates from the south Indian to the Pacific Ocean, inducing a quasi-stationary blocking high system over the Tasman Sea. This anticyclonic anomaly can then advect hot dry air towards the southern Victorian coast, where it produces HW conditions. On the other hand, extreme rainfall events mostly occur when the background conditions correspond to a La Niña state. The convection induced in the western Pacific can trigger a tropical-extratropical teleconnection over Queensland. This may generate an anticyclonic anomaly over the Tasman Sea, able to divert air parcels over a warm and humid area where conditions are, this time, favorable for more extreme rainfall along the Queensland coast. Springer-Verlag Berlin Heidelberg, 2014 Heat wave nationallicence Extreme rainfall nationallicence Sea surface temperature nationallicence Synoptic climatology nationallicence Blocking nationallicence Australian climate nationallicence Boschat Ghyslaine School of Earth Sciences, University of Melbourne, 3010, Melbourne, VIC, Australia aut Pezza Alexandre School of Earth Sciences, University of Melbourne, 3010, Melbourne, VIC, Australia aut Simmonds Ian School of Earth Sciences, University of Melbourne, 3010, Melbourne, VIC, Australia aut Perkins Sarah ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, NSW, Australia aut Cowan Tim CSIRO Marine and Atmospheric Research, Aspendale, VIC, Australia aut Purich Ariaan CSIRO Marine and Atmospheric Research, Aspendale, VIC, Australia aut Climate Dynamics Springer Berlin Heidelberg 44/7-8(2015-04-01), 1823-1840 0930-7575 44:7-8<1823 2015 44 382 https://doi.org/10.1007/s00382-014-2214-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-014-2214-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Boschat Ghyslaine School of Earth Sciences, University of Melbourne, 3010, Melbourne, VIC, Australia aut NATIONALLICENCE 700 1- Pezza Alexandre School of Earth Sciences, University of Melbourne, 3010, Melbourne, VIC, Australia aut NATIONALLICENCE 700 1- Simmonds Ian School of Earth Sciences, University of Melbourne, 3010, Melbourne, VIC, Australia aut NATIONALLICENCE 700 1- Perkins Sarah ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, NSW, Australia aut NATIONALLICENCE 700 1- Cowan Tim CSIRO Marine and Atmospheric Research, Aspendale, VIC, Australia aut NATIONALLICENCE 700 1- Purich Ariaan CSIRO Marine and Atmospheric Research, Aspendale, VIC, Australia aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 44/7-8(2015-04-01), 1823-1840 0930-7575 44:7-8<1823 2015 44 382