Australia suffered a long‐lasting extensive drought in 2019 with catastrophic wildfires creating about $4.4 billion damages, the worst record in the recent four decades. Concurrent with this extreme drought, the tropical Indo‐Pacific oceans exhibited an extraordinary combination of sea surface temperature (SST) anomalies, characterized by a Central‐Pacific (CP) El Niño event with westernmost location and the third strongest positive Indian Ocean Dipole (IOD) event. We here show evidence that this unique combination was responsible for the pan‐Australian drought as a westward located CP El Niño event and a strong positive IOD event can exacerbate precipitation reduction in northeastern and southern Australia, respectively. These continent‐wide extreme droughts could become more frequent over Australia in a warming world, considering projected increases in both CP El Niño and extreme positive IOD events superimposed on secular warming and drying trends.

中文翻译：

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热带印度太平洋太平洋复合热条件驱使2019年澳大利亚极端干旱

澳大利亚在2019年遭受了长期广泛的干旱，灾难性的野火造成了约44亿澳元的损失，这是最近四十年来最糟糕的记录。与这种极端干旱同时发生的是，印度洋-太平洋热带地区表现出异常的海面温度（SST）异常组合，其特征是中太平洋（CP）的厄尔尼诺事件（CPN）位于最西端，印度洋偶极子（IOD）位居第三）事件。我们在这里显示的证据表明，这种独特的组合是造成泛澳大利亚干旱的原因，因为位于西偏的CP ElNiño事件和强烈的IOD事件可以分别加剧澳大利亚东北部和南部的降水减少。在全球变暖的情况下，这些遍及整个非洲大陆的极端干旱可能在澳大利亚变得更加普遍，