Local and Remote Drivers of Southeast Australian Drought

C.M. Holgate*, A.I.J.M. Van Dijk, J.P. Evans, A.J. Pitman

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

13 Citations (Scopus)

Abstract

Droughts are associated with large-scale modes of variability, synoptic-scale systems, and terrestrial processes. Quantifying their relative roles in influencing drought guides process understanding, helps identify weaknesses in climate models, and focuses model improvements. Using a Lagrangian back-trajectory approach we provide the first quantification of the change in moisture supply during major droughts in southeast Australia, including the causes of the changes. Drought onset and intensification were driven by reduced moisture supply from the ocean, as moisture was circulated away from the region, combined with an absence of precipitation-generating mechanisms over land. During termination, strengthened moist easterly flows from the Tasman and Coral Seas promoted anomalously high rainfall. Our approach reveals terrestrial moisture sources played a secondary role, amplifying rainfall anomalies by less than 6%. Simulating droughts therefore requires deeper understanding of the relationship between moisture advection and synoptic-scale circulation and how large-scale climate variability and terrestrial processes modify these relationships.
Original languageEnglish
Article numbere2020GL090238
JournalGeophysical Research Letters
Volume47
Issue number18
DOIs
Publication statusPublished - 28 Sep 2020
Externally publishedYes

Keywords

  • Australia
  • drought
  • land-atmosphere feedback
  • moisture advection
  • moisture transport

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