Testing methods for reconstructing glacial Antarctic circumpolar current transport in an isotope-enabled climate model

A robust method to reconstruct the ACC baroclinic transport is helpful to assess the ACC's sensitivity to a changed climate. Here we test the reconstruction methods at the Last Glacial Maximum (LGM; similar to 20 ka) using end-member water masses in a fully coupled, isotope-enabled Community Earth System Model.

Model results suggest that the density profile at the northern side of ocean margins across the ACC can be reconstructed well from end-member water masses of Subtropical Surface Water (STSW), Antarctic Intermediate Water (AAIW), and Lower Circumpolar Deep Water. One additional pore fluid observation at 1,000 m can substantially improve transport reconstruction and is essential to constrain the sign of change in ACC transport during the LGM.