Details

Autor(en) / Beteiligte

• Kapsch, Marie‐Luise
• Mikolajewicz, Uwe
• Ziemen, Florian
• Schannwell, Clemens

Titel

Ocean Response in Transient Simulations of the Last Deglaciation Dominated by Underlying Ice‐Sheet Reconstruction and Method of Meltwater Distribution

Ist Teil von

• Geophysical research letters, 2022-02, Vol.49 (3), p.n/a

Ort / Verlag

Washington: John Wiley & Sons, Inc

Erscheinungsjahr

2022

Link zum Volltext

Quelle

Wiley Online Library

Beschreibungen/Notizen

• The last deglaciation was characterized by drastic climate changes, most prominently melting ice sheets. Melting ice sheets have a significant impact on the atmospheric and oceanic circulation, due to changes in the topography and meltwater release into the ocean. In a set of transient simulations of the last deglaciation with the Max Planck Institute for Meteorology Earth System Model we explore differences in the climate response that arise from different boundary conditions and implementations suggested within the Paleoclimate Modeling Intercomparison Project ‐ Phase 4 (PMIP4) deglaciation protocol. The underlying ice‐sheet reconstruction dominates the simulated deglacial millennial‐scale climate variability in terms of timing and occurrence of observed climate events. Sensitivity experiments indicate that the location and timing of meltwater release from the ice sheets into the ocean are crucial for the ocean response. The results will allow a better interpretation of inter‐model differences that arise from different implementations proposed within the PMIP4 protocol. Plain Language Summary The last deglaciation marked the transition between the last glacial maximum (LGM; about 21,000 years ago) and present. It was characterized by the disappearance of most northern hemispheric ice sheets (e.g., over North America and Eurasia) and a series of abrupt climate events. To investigate the ability of climate models to simulate the last deglaciation and to better understand the physical processes behind the changes, the Paleoclimate Modeling Intercomparison Project ‐ Phase 4 (PMIP4) has designed a common protocol for model simulations of the last deglaciation. This protocol comprises several choices on how to set up the model systems participating in this exercise. With a state‐of‐the‐art climate model, we explore how model simulations of the last deglaciation differ if different boundary data and methods proposed in the protocol are used. Our simulations show that the ice‐sheet boundary condition impacts the atmospheric and oceanic circulation during the LGM until about 14,000 years ago. It also determines the timing and occurrence of abrupt climate events throughout the deglaciation. These and further sensitivity experiments presented in this study will help to interpret the differences between model simulations that will be submitted for the PMIP4 deglaciation exercise. Key Points Transient simulations of the last deglaciation with the comprehensive Max Planck Institute for Meteorology Earth System Model 1.2 Glacial climate and millennial‐scale climate variability depend significantly on boundary conditions and methods proposed in Paleoclimate Modeling Intercomparison Project ‐ Phase 4 (PMIP4) deglaciation protocol Estimating uncertainties for interpretation of differences in PMIP4 model ensemble of the last deglaciation