Variability of soil moisture proxies and hot days across the climate regimes of Australia

A. Holmes, C. Rudiger, Brigitte Mueller, Martin Hirschi, N. Tapper

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7 Citations (Scopus)


The frequency of extreme events such as heat waves are expected to increase due to the effect of climate change, particularly in semiarid regions of Australia. Recent studies have indicated a link between soil moisture deficits and heat extremes, focusing on the coupling between the two. This study investigates the relationship between the number of hot days (Tx90) and four soil moisture proxies (Standardized Precipitation Index, Antecedent Precipitation Index, Mount's Soil Dryness Index, and Keetch-Byram Drought Index), and how the strength of this relationship changes across various climate regimes within Australia. A strong anticorrelation between Tx90 and each moisture index is found, particularly for tropical savannas and temperate regions. However, the magnitude of the increase in Tx90 with decreasing moisture is strongest in semiarid and arid regions. It is also shown that the Tx90-soil moisture relationship strengthens during the El Niño phases of El Niño–Southern Oscillation in regions which are more sensitive to changes in soil moisture.

Original languageEnglish
Pages (from-to)7265-7275
Number of pages11
JournalGeophysical Research Letters
Issue number14
Publication statusPublished - 28 Jul 2017


  • Land/atmosphere interactions, Drought, Extreme events, Evapotranspiration, Soil moisture, soil moisture, hot days

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