Ventilation of the deep Gulf of Mexico and potential insights to the Atlantic Meridional Overturning Circulation

Ventilation in the deep Gulf of Mexico (GoM), its connection to the North Atlantic, and its susceptibility to changes of the Atlantic Meridional Overturning Circulation are investigated by combining observations of raculation Model (GCM) ensemble output. Radiocarbon data and multiannual volume transport through the Yucatan Channel suggest deep water residence times similar to 100 years for the GoM. Comparisons to previous radiocarbon observations suggest that the deep GoM has aged in the recent past, consistent with observed raising temperatures and the CMIP6 GCM simulations. The distribution of radiocarbon indicates a time frame of similar to 160 years between North Atlantic convection and complete ventilation of the deep GoM. This suggests that aging and warming of GoM deep waters were initiated in the North Atlantic before similar to 1890 consistent with reported rapid and persistent AMOC weakening since the Little Ice Age.

Automated summary

This study investigates the ventilation in the deep Gulf of Mexico, its connection to the North Atlantic, and its sensitivity to changes in Atlantic Meridional Overturning Circulation (AMOC). Using radiocarbon data and transport measurements, it is found that the residence time of deep water in the Gulf of Mexico is approximately 100 years. Comparisons with previous radiocarbon observations suggest that the deep Gulf of Mexico has aged in recent years, which is consistent with temperature increases and CMIP6 global circulation model simulations. The distribution of radiocarbon indicates that there is a time lag of around 160 years between North Atlantic convection and complete ventilation of the deep Gulf of Mexico, suggesting that the aging and warming of deep waters in the Gulf of Mexico were initiated in the North Atlantic before approximately 1890, which aligns with the reported rapid and persistent weakening of AMOC since the Little Ice Age.