Aim of the ASIMBO 2018 campaign is to complement earlier ice thickness measurements made by plane or helicoter north of Svalbard, Greenland and in Fram Strait. Sea ice thickness information will be used to examine the connection between thickness variability, ice age and source area. Together with satellite based information on sea ice motion, data will be used to quantify sea ice outflow through Fram Strait in summer. These estimates shall improve the understanding of interannual variability in summer sea ice outflow and complement existing winter volume flux calculations. A second objective is to extent sea ice thickness measurements to the Lincoln Sea where we will study thinning of sea ice due to reduction of old multi-year ice in this area. Like the measurements planned over the Fram Strait area, the surveys are a continuation of earlier aircraft campaigns made north of Alert and shall improve understanding of ice mass balance changes in the Arctic.