A revised Earth system model-based analysis of glacial-interglacial changes in ocean δ13C
Differences in fw are found to be central for distinguishing our best representations of HOL and LGM δ13C patterns. These simulations reproduce well the deglacial weakening of the surface-to-deep ocean δ13C gradient. For both time slices, good fits to the proxy data are however achieved for several combinations of br and fw. To account for uncertainty in the ensemble simulations, we correct the ensemble for model-data bias and weight them by model skill. From this, we compute an ensemble average difference in whole-ocean δ13C between LGM and HOL of 0.22 – 0.34‰. This translates to an addition of 340 – 520 Pg C with a terrestrial δ13C signature to the LGM ocean. In the next step, we expand the study by exploring the effect of interactive sediments on these results.