The Indian Ocean Dipole (IOD) and Tripole (IOT) represent primary modes of interannual variability in the Indian Ocean, impacting both regional and global climate. Unlike the IOD, which is closely related to the El Niño-Southern Oscillation (ENSO), our findings unveil a substantial influence of the Australian Monsoon on the IOT. An anomalously strong Monsoon induces local sea surface temperature (SST) variations via the wind-evaporation-SST mechanism, triggering atmospheric circulation anomalies in the eastern Indian Ocean. These circulation changes lead to changes in oceanic heat transport, facilitating the formation of the IOT. Our analysis reveals a strengthening connection between the Australian Monsoon and the IOT in recent decades, with a projected further strengthening under global warming. This contrasts with the diminished coupling between ENSO and IOD in recent decades from observations and model projections, illustrating evolving Indian Ocean dynamics under the warming climate.

印度洋偶极子 （IOD） 和三极子 （IOT） 代表了印度洋年际变率的主要模式，影响区域和全球气候。与与厄尔尼诺-南方涛动 （ENSO） 密切相关的 IOD 不同，我们的研究结果揭示了澳大利亚季风对物联网的重大影响。异常强的季风通过风-蒸发-SST 机制引起局部海面温度 （SST） 变化，引发东印度洋的大气环流异常。这些环流变化导致海洋热传输发生变化，从而促进了 IOT 的形成。我们的分析揭示了近几十年来澳大利亚季风与 IOT 之间的联系加强，预计在全球变暖的情况下会进一步加强。这与近几十年来观测和模式预测中 ENSO 和 IOD 之间的耦合减弱形成鲜明对比，这说明了气候变暖下印度洋动力学的演变。