Ice flow of Humboldt, Petermann and Ryder Gletscher, northern Greenland

Radar interferometry, ice-penetrating radar profiles and an elevation model are used to determine the velocity fields, rates of ice discharge, approxi mate states of balance and catchment area for three large outlet glaciers i n northeast Greenland. Discharge through flux gates is calculated for Humbo ldt and Petermann Gletscher, which are found to be in balance (at the level that the accumulation is known). A large difference between the measured a nd estimated fluxes for Ryder Gletscher may be a reflection of unsteady flo w behavior for this glacier. The patterns of ice flow for the three glacier s considered are each unique, showing that the nature of ice discharge vari es substantially from basin to basin, controlled by bed conditions and the presence of subglacial troughs and obstructions.