1116 / 2024-09-20 13:37:03

Coupled Glacier-Climate simulation of the Third Pole during LGM and beyond

glacier,third pole,simulation,paleocliamte

The Third Pole comprises the largest global inventory of frozen water after the polar regions. Glaciers on the Third Pole were much more extensive than present during the Last Glacial Maximum when the global mean temperature was approximately 4-8 K lower than today. The exact extent is still debated due to the uncertainties and scarcity in reconstruction data. Accurate reconstruction of these glaciers remains vital towards understanding glaciers' sensitivity against climate change, and the response of our climate system's key components toward changes in glaciers.

Recognizing the difficulty in constraining all of the Third Pole's glaciers through field-studies, we attempt to achieve this goal through means of numerical simulation. Previous studies commonly neglect the feedbacks of the glaciers toward the climate system. We address this issue by building a coupler that couples a climate model/earth system model to an ice-sheet model, with the option of using Positive Degree Day method or Energy Balance Method to calculate surface mass balance. This was the first time, to the best of our knowledge, that a LGM simulation was done for the Third Pole with two-way coupled ice-sheet and climate model.

Our results show ~20% difference in glacier volume and marked changes in distribution, providing better agreement with reconstructions, indicating the interaction between Tibetan Plateau glaciers and climate was significant and should not be neglected. The coupling framework in this study is being applied to other glaciation events.