Abstract: The overturning circulation of the Southern Ocean (SO) drives the exchange of water masses between high and low latitudes in the Southern Hemisphere (SH). Concurrently, the tropical Pacific serves as a crucial source of global water vapor and heat, influencing key processes such as the Hadley and Walker circulations and the El Ni?o-Southern Oscillation (ENSO). These processes effectively transport heat from tropical regions to higher latitudes and foster interactions between atmospheric circulations across the SH on interannual to decadal timescales. During glacial cycles, complex interactions between oceanic and atmospheric circulations are evident between the tropical Pacific and the SO, involving significant exchanges of matter and energy that impact global climate change. High-latitude ice and sediment cores’ records have extensively documented the evolution of sea surface temperatures and sea ice of SO, as well as Antarctic precipitation influenced by ENSO-like processes during glacial cycles. Meanwhile, tropical sediment core records indicate that subsurface warming of the Indo-Pacific Warm Pool during these cycles results from excess heat from the SO being transported northwards via shallow overturning cell and subtropical circulations. These records not only support the notion that enhanced SO circulation affects biogeochemical cycles and material exchanges in low-latitude oceans but also suggest that glacial cycle-induced warming of the Indo-Pacific Warm Pool could trigger ENSO-like changes, dominating tropical Pacific atmospheric circulation patterns and impacting SO atmospheric circulation. However, due to the limited paleoceanographic records of tropical teleconnections across multiple timescales, significant uncertainties remain in understanding and assessing the interaction processes and mechanisms between the SO and the tropical Pacific. Therefore, ongoing investigations and analyses of multi-proxy circum-Antarctic sediment cores are essential to provide more accurate environmental change parameters for tropical teleconnection climate models, thereby reducing these uncertainties.

Key words: ENSO/SAM-like, atmospheric bridge, oceanic tunnel, tropical teleconnections, paleoceanographic records, Southern Ocean, tropical Pacific Ocean