Laurentide ice saddle mergers drive rapid sea level drops during glaciations

This is PISM v1.0 simulation data from a steady-state simulating the glaciation of Laurentide Ice Sheet by decreasing equilibrium-line altitude (ELA).  We use a hybrid stress balance scheme in PISM (shallow ice approximation + shallow shelf approximation) and a thickness-based calving criterion. The horizontal resolution is 20 km. it includes three ELA decreasing speeds (ELA gradually decreases in 20 kyr, 100kyr, and step changes).