Seesaw Terrestrial Wetting and Drying Between Eastern and Western Australia.

Australia, the driest inhabited continent, is prone to natural disasters, such as droughts, floods, bushfires, and heatwaves. Strong climate variability causes recurring threats to water supply, agriculture, and the environment. Improving our insight into changes in hydroclimatic patterns is required to provide useful information for society. Previous studies mainly focused on the causes of extreme wet or dry events in specific periods and their impacts on agriculture and ecosystems. An understanding of long‐term spatio‐temporal patterns of wetting and drying in Australia is still lacking. Here we show, based on analyses of Gravity Recovery and Climate Experiment satellite derived terrestrial water storage and extended datasets, that there are four consecutive periods of seesaw wetting and drying between eastern and western Australia in the past five decades. The seesaw phenomenon is characterized by eastern Australia gaining water, while western Australia is losing water, and vice versa. Strong La Niña induced continent‐wide wetting, resets this pattern, leaving each seesaw to last for 11 ± 5 years. We provide one possible mechanism related to vegetation response to climate variability and its feedback on hydrological processes to explain the seesaw pattern. The identified recurring seesaw pattern indicates that society would need to become more adaptive in managing forest, water, and disaster risks in the wake of a next strong La Niña induced continent‐wide wetting in Australia. Plain Language Summary: Here, we report for the first time a vegetation mediated seesaw wetting/drying phenomenon between eastern and western Australia. The seesaw phenomenon is characterized by eastern Australia gaining water, while western Australia is losing water, and vice versa. It is reset by strong La Niña induced continent‐wide wetting. The seesaw phase seems to depend on vegetation cover anomaly prior to the strong La Niña event, and can be explained by subsequent vegetation and soil moisture interactions. This finding provides society with valuable reference for managing forest, water, and disaster risks in the wake of a next strong La Niña induced continent‐wide wetting in Australia. Key Points: A seesaw wetting/drying phenomenon between eastern and western Australia is revealed for the first timeThis terrestrial water storage (TWS) seesaw pattern is reset by strong La Niña induced continent‐wide wettingThe TWS seesaws appear to be resulting from vegetation mediated hydrological responses to decadal precipitation variability [ABSTRACT FROM AUTHOR]