The Influence of Atmosphere-Ocean Phenomenon on Water Availability Across Temperate Australia

Links between climate variability modes, rainfall, and streamflow are important for understanding the trajectories of change and dynamics in water availability. In this study, we examined the influence of the El Nino Southern Oscillation, Indian Ocean Dipole, Southern Annular Mode, and Interdecadal Pacific Oscillation modes on interannual variations in rainfall and streamflow in four hydroclimate regions. We also explored the link between climate variability modes and extreme rainfall and streamflow years. Climate mode indices, rainfall, and streamflow data from 1975 to 2018 were analyzed for 92 predominately forested catchments located across temperate Australia. Climate modes had divergent influences on streamflow and rainfall between and within regions. Across temperate Australia, a higher proportion of interannual variation in rainfall was explained by climate modes than for streamflow, indicating factors other than atmosphere-ocean phenomena are important in determining interannual streamflow variability. Extremes in rainfall and streamflow across regions were related to the co-occurrence of climate modes, with a stronger relationship between teleconnections and low rainfall/streamflow years than high rainfall/streamflow years. The study provides new insights into the regional drivers of hydrological extremes and consolidates our understanding of the role of teleconnections on water availability in the temperate zone of Australia.

Automated summary

This study examined the influence of climate variability modes on rainfall and streamflow in temperate Australia, finding divergent impacts of climate modes on streamflow and rainfall between and within regions. It also highlighted the importance of factors other than atmosphere-ocean phenomena in determining interannual streamflow variability in the temperate zone of Australia. The study provides new insights into the regional drivers of hydrological extremes and the role of teleconnections on water availability.