Negative Indian Ocean Dipole drives groundwater recharge in southeast Australia

Abstract

Abstract Understanding how Australian groundwater recharge is affected by the Pacific and Indian Ocean climate drivers is crucial for water resource planning and management, especially in semi-arid environments. This will allow for assessment of the impact of climate change on the occurrence and timing of groundwater recharge and the sustainable management of this resource into the future. Measuring groundwater recharge is difficult as it occurs in the subsurface. However, caves situated in the unsaturated zone give us the opportunity to observe these subsurface processes. Here we show good agreement between the recharge events measured in a cave system and groundwater bores at a nearby site. We also show that the most significant recharge event during a decade of observations occurred during a particularly strong negative Indian Ocean Dipole period. Through further analysis of recharge events dating back 1900 we show for the first time a significant link with negative Indian Ocean Dipole events.