Thermal coupling of the Indo-Pacific warm pool and Southern Ocean over the past 30,000 years

Abstract

The role of the tropical Pacific Ocean and its linkages to the southern hemisphere during the last deglacial warming remain highly controversial. Here we explore the evolution of Pacific horizontal and vertical thermal gradients over the past 30 kyr by compiling 340 sea surface and 7 subsurface temperature records, as well as one new ocean heat content record. Our records reveal that La Niña-like conditions dominated during the deglaciation as a result of the more intense warming in the western Pacific warm pool. Both the subsurface temperature and ocean heat content in the warm pool rose earlier than the sea surface temperature, and in phase with South Pacific subsurface temperature and orbital precession, implying that heat exchange between the tropical upper water column and the extratropical Southern Ocean facilitated faster warming in the western Pacific. Our study underscores the key role of the thermal coupling between the warm pool and the Southern Ocean and its relevance for future global warming.

Middle Pleistocene re-organization of Australian Monsoon

“…In this context, strengthening of the Walker circulation and the suppression of El Niño events in the early Holocene have been related to increased upper ocean heat storage in the IPWP during the precessional minimum at 11.5 ka 82 , 88 , 89 . Recent compilations of upper ocean heat content records in the IPWP for the last glacial–interglacial cycles and transient climate simulations further highlighted the importance of precessional insolation as a driver of variability for the Austral–Asian Monsoon system 90 , 91 . These studies suggested, in particular, that precession-modulated variations in IPWP upper ocean heat content controlled the convergence of moisture and latent heat over the past 360 kyr, thus regulating the ocean-continent hydrological cycle within the Austral–Asian Monsoon domain 90 .…”