Mechanisms leading to the last glacial inception over North America: Results from the CLIMBER-GREMLINS atmosphere-ocean-vegetation northern hemisphere ice-sheet model - Archive ouverte HAL Accéder directement au contenu
Chapitre D'ouvrage Année : 2007

Mechanisms leading to the last glacial inception over North America: Results from the CLIMBER-GREMLINS atmosphere-ocean-vegetation northern hemisphere ice-sheet model

Résumé

The CLIMBER-GREMLINS model is an atmosphere-ocean-vegetation-northern hemisphere ice-sheet model able to simulate ice-sheet growth in response to the transient forcings (insolation and CO2 changes) of the period 126-106kyr BP. In the present version of the model, this growth mainly occurs over North America and reaches an equivalent of 17 m in sea-level drop. To quantify the role of the vegetation, ocean and icesheet feedbacks in this glaciation of North America, we have conducted sensitivity experiments in which the feedback of each of these components is sequentially switched off. These experiments show that, in this model. (1) glacial inception does not occur when vegetation is fixed to its interglacial state (experiment testing the response of the atmosphere-ocean-boreal land-ice system), (2) glacial inception occurs faster than in the standard experiment when the ocean surface characteristics (surface temperature and sea ice extent) are prescribed to their interglacial seasonal cycle (experiment testing the sensitivity of the atmosphere-vegetation-boreal land-ice system), (3) the ice-sheet albedo and altitude feedbacks are not crucial for starting the glaciation, but the albedo feedback doubles the ice volume growth rate, (4) the potential effect of a reduction in the thermohaline circulation is tested via an additional experiment in which we have forced it to its ‘off’ mode. The results show that this mode favours the fastest land ice growth of all our experiments.
Fichier non déposé

Dates et versions

hal-03030440 , version 1 (30-11-2020)

Identifiants

Citer

Masa Kageyama, Sylvie Charbit, Catherine Ritz, Myriam Khodri, Gilles Ramstein. Mechanisms leading to the last glacial inception over North America: Results from the CLIMBER-GREMLINS atmosphere-ocean-vegetation northern hemisphere ice-sheet model. The climate of past interglacials, F. Sirocko, M. Claussen, T. Litt and M. F. Sanchez-Goñi (Eds). Developments in Quaternary Science Series. 7, Elsevier, 573-582 (chapter 38), 2007, ⟨10.1016/S1571-0866(07)80063-7⟩. ⟨hal-03030440⟩
30 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More