Seesaw terrestrial wetting and drying between eastern and western Australia
Ajiao Chen, Huade Guan, Okke Batelaan
Received Date: 18th February 20
Australia, the driest inhabited continent, is prone to natural disasters, such as droughts, floods, bushfires and heatwaves. Strong climate variability causes regular threats to water supply, agriculture and the environment. Improving our insight into changes in hydroclimatic patterns is required to understand the cycles of wetting and drying in Australia and consequently contribute to predicting and managing future natural disasters. 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 GRACE satellite derived terrestrial water storage (TWS) analyses, that there are four continuous 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. The TWS seesaw phenomenon is substantiated by a similar pattern in the normalized difference vegetation index between eastern and western Australia. It appears that the seesaw phase is dependent on vegetation cover anomaly prior to the strong La Niña event. If the periodic seesaw pattern persists into the future, it will provide society with valuable opportunities for multi-year ahead-of-drought/flood planning for managing water, agriculture, and disaster risks in Australia.
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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.