Glacial Climate Variability

Funding programm: Bundesministerium für Bildung und Forschung
Funding identification number (FZK): 01LP2303A
Cost (Kostenstelle): DM 87011018
Project duration: January 01 2024 - December 31 2026
Applicants: Dr. Gregor Knorr | Prof. Dr. Gerrit Lohmann
PostDoc:     Dr. Lu Niu

 

In this Project we will simulate the spectrum of abrupt millennial-scale climate variability during MIS3 comprising both DO-oscillations and H-DO events. Including experiments with interactive ice sheet dynamics, we will examine essential differences between the two with the comprehensive model systems developed in PalMod. Focus of our investigations will be the analysis of basic dynamics and feedbacks of abrupt climate changes in response to changes in Earth orbital parameter and atmospheric greenhouse gas concentrations to provide characteristic transient MIS3 simulations. Besides these targets we aim to shed light on the cause and effect relationship of ice sheet and AMOC changes. Selected runs will be extended several millennia into the deglaciation period and complemented by the representation of stable oxygen isotopes. The results will be compared to proxy data to provide critical constraints for the evaluation of the transient simulations and to decipher mechanisms that are most consistent with the available data.

Figure: Characteristic pattern of surface mass balance (SMB) towards the establishment of full glacial ice sheet conditions. Accumulation (positive SMB) is most pronounced close to the central margin of the ice sheet, which is linked to moisture transport from the low latitude Atlantic and summer snowfall.

References

Niu, L., Lohmann, G., Gierz, P., Gowan, E. J. and Knorr, G. (2021): Coupled climate-ice sheet modeling of MIS-13 reveals a sensitive Cordilleran Ice Sheet. Global and Planetary Change, 200. Art.Nr. 103474. DOI 10.1016/j.gloplacha.2021.103474

Zhang, X., Barker, S., Knorr, G., Lohmann, G., Sun, Y, Drysdale, R. and D. Hodell (2021): Direct astronomical influence on abrupt climate variability. Nature Geosci. 14, 819–826. https://doi.org/10.1038/s41561-021-00846-6

Niu, L., Lohmann, G., & Gowan, E. J.(2019): Climate noise influences icesheet mean state. Geophysical ResearchLetters,46, 9690–9699. https://doi.org/10.1029/2019GL083717

Gowan, E.J., Zhang, X., Khosravi, S. et al. A new global ice sheet reconstruction for the past 80 000 years. Nat Commun 12, 1199 (2021). https://doi.org/10.1038/s41467-021-21469-w