Long-term trends and climate-mode controls on offshore wind power density off Australia

A national, multi-decadal assessment of Australia’s offshore wind power density (WPD) is presented using reanalysis winds at 10 m and 100 m for 1980–2019. Seasonal cycles, linear trends, interannual–decadal variability, return levels, and a variability index are evaluated. Operational relevance is enhanced by adding power-producing time fraction and run-length persistence from hourly winds. Variability and stability are further characterized using daily-to-annual mean winds and their standard deviations. Teleconnection controls from the El Niño–Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Antarctic Oscillation (AAO) are diagnosed. Maximum 10 m monthly WPD reaches 918.9 W/m² along the northeast coast and 1200.0 W/m² along the west coast over the 40-year record. In most regions, 100 m WPD exceeds 10 m WPD; near parts of the coast the difference is small and local exceptions occur. Time series at four representative sites show clear seasonal and interannual variability. Spatially, a meridional contrast is evident: WPD strengthens across the Southern Ocean, while parts of 30–40° S show weaker or opposite tendencies; the zonal increase south of ∼45° S is consistent with intensifying westerlies. ENSO modulates winds along the southern margin (El Niño weaker, La Niña stronger) and positive AAO shifts and intensifies the westerly jet poleward, enhancing WPD in higher southern latitudes. These results provide teleconnection-aware climatology to support site selection, long-term yield estimation, and design for seasonal and extreme conditions, and to reduce investment risk in Australia’s emerging offshore wind sector.