Impact of the North American ice-sheet orography on the Last Glacial Maximum eddies and snowfall

• Published in: Geophysical Research Letters
• Main Authors: Kageyama, Masa, Valdes, Paul
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modélisation du climat (CLIM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), DEPARTMENT OF METEOROLOGY UNIVERSITY OF READING GBR, University of Reading (UOR)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2000
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Ice Sheet; North Atlantic
• Online Access: https://hal.science/hal-02930149; https://hal.science/hal-02930149/document; https://hal.science/hal-02930149/file/1999GL011274.pdf; https://doi.org/10.1029/1999GL011274

International audience The present work evaluates the influence of the North American ice-sheet orography on the Last Glacial Maximum (LGM, 21,000 years ago) atmospheric circulation and snowfall in the northern mid-latitudes, focusing on the North Atlantic sector. Three Atmospheric General Circulation Model experiments are analysed: a control and an LGM climate simulation, and an LGM run with "fiat" ice-sheets over northern North America. This ice-sheet orography affects lee-cyclogenesis over North America and forces differences in stationary waves and therefore in the baroclinicity of the mean flow. As a result, the Atlantic storm-track is reinforced in the "fiat ice-sheet" experiment compared to the LGM one. This, in turn, has a profound impact on snowfall over northern Europe, implying a coupling between the two ice-sheets.