EGU22-9793, updated on 09 Jun 2023
https://doi.org/10.5194/egusphere-egu22-9793
EGU General Assembly 2022
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Numerical reconstructions of the Patagonian Ice Sheet: Growth and demise through the Late Quaternary

Andrés Castillo1,2, Matthias Prange1, Jorjo Bernales1,3, Franco Retamal-Ramírez4,5,6, Michael Schulz1, and Irina Rogozhina2,7
Andrés Castillo et al.
  • 1MARUM Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, 28334 Bremen, Germany
  • 2Department of Geography, Norwegian University of Science and Technology, Trondheim, 7049, Norway
  • 3Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands
  • 4Departamento de Geofísica, Universidad de Concepción, Concepción, Chile
  • 5Center for Climate and Resilience Research (CR)2, Chile
  • 6Centro de Investigación Gaia Antártica, Universidad de Magallanes, Punta Arenas, Chile
  • 7Departamento de Ciencias de la Tierra, Universidad de Concepción, Concepción, Chile.

Glacial geomorphological and geochronological studies suggest that the Patagonian Ice Sheet (PIS) stretched from 38°S to 55°S during the Marine Isotope Stages (MIS) 2-3. While its western margin reached the Pacific Ocean, the easternmost sectors of the PIS were characterized by terrestrial lobes that fed large paleo glacial lakes after its maximum extension towards the end of the MIS 3. An ice-marginal stabilization occurred throughout the global Last Glacial Maximum followed by a rapid deglaciation after 18,000 yr before present.

Here we present an ensemble of transient numerical simulations of the PIS that have been carried out to provide information on its thickness and extents through the MIS 3 and MIS 2. Our aim here is to determine the range of climate conditions that matches the field-derived ice sheet geometries and the timing of local deglaciation, while bracketing the spread in possible ice volumes and sea level contributions originating from uncertainties in the internal parameters and external forcings. The model ensemble makes use of the new higher-order version of the ice sheet model SICOPOLIS forced by combination of present-day atmospheric conditions from the ERA5 reanalysis and outputs from the Paleoclimate Modeling Intercomparison Project (PMIP) and new Community Earth System Model (CESM) experiments. Our results indicate that the regional climate conditions required to reproduce a realistic growth and demise of the PIS through the Late Quaternary are not captured by coarse-resolution global climate models, implying the necessity of high spatial-resolution regional modeling. Our results also suggest that in order to realistically simulate the evolution of the PIS in agreement with geological archives, the MIS3 should have witnessed colder regional temperatures in and around Patagonia than those shown by global climate models for the MIS 2.

How to cite: Castillo, A., Prange, M., Bernales, J., Retamal-Ramírez, F., Schulz, M., and Rogozhina, I.: Numerical reconstructions of the Patagonian Ice Sheet: Growth and demise through the Late Quaternary, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9793, https://doi.org/10.5194/egusphere-egu22-9793, 2022.

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