How oceanic oscillation drives soil moisture variations over mainland Australia: An analysis of 32 years of satellite observations*

Bernhard Bauer-Marschallinger*, Wouter A. Dorigo, Wolfgang Wagner, Albert I.J.M. Van Dijk

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

27 Citations (Scopus)

Abstract

Australia is frequently subject to droughts and floods. Its hydrology is strongly connected to oceanic and atmospheric oscillations (climate modes) such as the El Niño-Southern Oscillation (ENSO), Indian Ocean dipole (IOD), and southern annular mode (SAM). A global 32-yr dataset of remotely sensed surface soil moisture (SSM) was used to examine hydrological variations in mainland Australia for the period 1978-2010. Complex empirical orthogonal function (CEOF) analysis was applied to extract independent signals and to investigate their relationships to climate modes. The annual cycle signal represented 46.3% of the total variance and a low but highly significant connection with SAM was found. Two multiannual signals with a lesser share in total variance (6.3%and 4.2%) were identified. The first one had an unstable period of 2-5 yr and reflected an east-west pattern that can be associated with ENSO and SAMbut not with IOD. The second one, a 1-to 5-yr oscillation, formed a dipole pattern between the west and north and can be linked to ENSO and IOD. As expected, relationships with ENSO were found throughout the year and are especially strong during southern spring and summer in the east and north. Somewhat unexpectedly, SAM impacts strongest in the north and east during summer and is proposed as the key driver of the annual SSM signal. The IOD explains SSMvariations in the north, east, and southeast during spring and also in the west during winter.

Original languageEnglish
Pages (from-to)10159-10173
Number of pages15
JournalJournal of Climate
Volume26
Issue number24
DOIs
Publication statusPublished - Dec 2013
Externally publishedYes

Keywords

  • Australia
  • Hydrology
  • Oceanic variability
  • Remote sensing
  • Satellite observations
  • Soil moisture

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