- 1University of Bern, Physics Institute, Climate and Environmental Physics, Bern, Switzerland
- 2Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
- 3Australian Antarctic Division, Kingston, Australia
The ocean is the largest heat reservoir of the planet active on millennial to orbital time scales. By observing and reconstructing its temperature changes – together with the evolution of ice sheet volume – insights on the distribution of Earth’s energy balance may be traced though time (Baggenstos et al., 2019).
MOT is reconstructed in our studies from noble gases trapped within ice cores. Noble gases are inert: as a result, they partition in a simple two reservoirs system: the atmosphere and the ocean and are not affected by biological cycles in the ocean. As the atmospheric concentration of noble gases is tied to their solubility in the ocean, and the latter is in turn mostly temperature dependent, the concentration recorded within ice cores gas bubbles or clathrates creates a continuous atmospheric record through time. As heat and noble gases are conservatively entrained into the interior of the ocean, we stress that with our MOT approach we obtain the integrated ocean heat content at a given point in time, integrating over all water parcels of the ocean which have different ventilation ages, hence which have equilibrated at the ocean surface at different points back in time. Accordingly, MOT is a convoluted signal of past sea surface temperatures biased towards regions of deep and intermediate water formation.
The majority of MOT analyses carried out thus far have focused on glacial terminations. Here, we build upon the already existing TIV & TIII data to present early results focused on the glacial cycle in-between. The EPICA Dome C ice core is used to reconstruct MOT fluctuation during Marine Isotope Stage 8 (MIS 8: 255 – 330 ka) with a millennia-scale resolution. This allows to look in the detail of a glacial inception and investigate the mechanisms triggering the onset of glaciation.
Baggenstos, D., Häberli, M., Schmitt, J., Shackleton, S. A., Birner, B., Severinghaus, J. P., Kellerhals, T., & Fischer, H. (2019). Earth’s radiative imbalance from the Last Glacial Maximum to the present. Proceedings of the National Academy of Sciences of the United States of America, 116(30), 14881–14886. https://doi.org/10.1073/pnas.1905447116
How to cite: Traeger, H., Grimmer, M., Schmitt, J., Baggenstos, D., and Fischer, H.: Reconstructing Mean Ocean Temperature over a full glacial cycle using noble-gas ratios from the EDC ice core, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14884, https://doi.org/10.5194/egusphere-egu25-14884, 2025.
