The Indian Ocean Dipole (IOD) is one of the major climate modes in the tropical Indian Ocean (TIO), influencing the surrounding climate and society. Under anthropogenic warming, the IOD is modulated by the changes in the ocean–atmosphere coupling in the TIO. This study focuses on the IOD seasonal phase locking, which means that the IOD usually peaks in boreal autumn. Based on high-emission scenario future projections, we found that the IOD phase locking changes substantially under anthropogenic warming. The early onset positive IOD that peaks in boreal summer occurs more frequently in the future climate. Our further investigation reveals that this robust change in IOD phase locking is related to the mean state responses to global warming. The shallower thermocline in the eastern equatorial IO is more suitable for IOD developing, helping IOD strengthen in boreal summer. When the basin-wide IOD pattern has fully developed, by contrast, the weakened atmospheric feedback is not conducive to maintaining zonal sea surface temperature gradient, leading to IOD weakened in boreal autumn. Therefore, the IOD peaks earlier under global warming. The change in IOD phase locking shows a potential impact on the surrounding climate, such as Indian summer monsoon variability.

印度洋偶极子（IOD）是热带印度洋（TIO）的主要气候模式之一，影响着周围的气候和社会。在人为变暖下，IOD 受 TIO 中海洋-大气耦合变化的调节。本研究侧重于 IOD 季节性锁相，这意味着 IOD 通常在北方秋季达到峰值。基于高排放情景的未来预测，我们发现在人为变暖下IOD锁相发生显着变化。在北方夏季达到峰值的早发正 IOD 在未来气候中更频繁地出现。我们的进一步调查表明，IOD 锁相的这种强劲变化与对全球变暖的平均状态响应有关。东赤道IO较浅的温跃层更适合IOD发育，帮助 IOD 在北方夏季加强。相比之下，当全流域IOD模式完全发展时，减弱的大气反馈不利于维持纬向海面温度梯度，导致北方秋季IOD减弱。因此，在全球变暖的情况下，IOD 会更早达到峰值。IOD 锁相的变化显示了对周围气候的潜在影响，例如印度夏季风变率。