During the last deglaciation abrupt millennial-scale perturbations of the Atlantic Meridional Overturning Circulation massively altered the interhemispheric heat distribution affecting, for example, continental ice volume and hydroclimate. If and how the related cross-equatorial heat transport was controlled by the interplay between the southward-flowing Brazil Current (BC) and northward-flowing North Brazil Current (NBC) remains controversial. To assess the role of tropical heat transport during the last deglaciation, we obtained a high-resolution foraminiferal Mg/Ca-based sea surface temperature (SST) record from the BC domain at 21.5°S. The data reveal a yet undocumented warming of at least 4.6°C of the BC during Heinrich Stadial 1 at ∼16 ka indicating massive oceanic heat accumulation in the tropical South Atlantic. Simultaneously, a strongly diminished NBC prevented the release of this excess heat into the northern tropics. The observed magnitude of heat accumulation substantially exceeds numerical model simulations, stressing the need to further scrutinize atmospheric and oceanic heat transport during extreme climatic events.

中文翻译：

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在最后一次冰消期间，热带大西洋在半球间热传输中的作用

在最后一次冰消作用期间，大西洋子午翻转环流的千年尺度突然扰动极大地改变了半球间的热分布，从而影响了例如大陆的冰量和水文气候。是否以及如何通过向南流动的巴西洋流（BC）和向北流动的北巴西洋流（NBC）之间的相互作用来控制相关的跨赤道热传输仍然存在争议。为了评估热带热传输在最后一次冰消作用中的作用，我们从21.5°S的BC域获得了高分辨率的有孔虫以Mg / Ca为基础的海面温度（SST）记录。数据显示，在Heinrich Stadial 1期间，大约16 ka时，BC至少有4.6°C的变暖，目前尚无记录，表明热带南大西洋有大量海洋热量积聚。同时地，NBC的急剧减少阻止了多余的热量释放到北热带。观察到的热量累积量大大超过了数值模型模拟，从而强调了在极端气候事件期间需要进一步审查大气和海洋热量传输的需求。