Role of the ice sheet dynamics during the past climatic changes of the last glaciation.

This thesis investigates the dynamics of the ice sheets that appeared in the northern hemisphere during the last glacial periods. Starting with the Antarctic ice sheet model GRISLI, developed at the LGGE, improvements of the physics are made in oder to alppy the model to the northern hemisphere. A determination of a realistic ice shelf front is made and associated boundary condition were developed at the front of the ice shelves. A basal hydrology scheme is implemented and a treshold based on basal water pression allows a more realistic ice streams localisation. This new ice sheet model is applied to the northern hemisphere to reconstruct the ice sheets evelolution during the last glacial period and compare the relative influence of surface mass balance and ice dynamics. Eurasian ice sheet around the 90,000 years (BP) was investigated in more details to study the impact of ice dammed lakes and the role of the ice shelves during the inception and the deacy of a marine ice sheet in Barents and Kara Seas