Constraints on Southern Australian Rainfall Change Based on Atmospheric Circulation in CMIP5 Simulations

• DOI: 10.1175/jcli-d-16-0142.1
• Publication Date: 2016-09-29T20:48:20Z
• Authors: Michael R. Grose; James S. Risbey; Aurel F. Moise; Stacey Osbrough; Craig Heady; Louise Wilson; Tim Erwin
• Keywords: Storm track; Polar front; Atmospheric Circulation; Longitude; Middle latitudes

Atmospheric circulation change is likely to be the dominant driver of multidecadal rainfall trends in midlatitudes with climate this century. This study examines features relevant southern Australian January and July explores emergent constraints suggested by intermodel spread their impact on resulting projection CMIP5 ensemble. The authors find relationships between models’ bias projected for four July, each suggestions constraining forced change. are strength subtropical jet over Australia, frequency blocked days eastern longitude peak blocking east latitude storm track within polar front branch split jet. Rejecting models where suggests either direction or magnitude implausible produces a constraint reduction Australia. For RCP8.5 end century constrained projections at least 5% (with showing increase little being rejected). these projections, assumption affects entire simulation, leads rejection wet dry outliers.