ASIMBO summer 2018

Aim of the aircraft campaign “ASIMBO summer” is to conduct sea ice surveys over different ice regimes when sea ice is close to its minimum extent. The surveys complement earlier measurements carried out in Fram Strait, central Arctic Ocean and Lincoln Sea with RV Polarstern and Polar 5/6 between 2001 and 2017. To minimize payload and extent flight range, measurements will be restricted to a determination of sea ice thickness and freeboard using the EM-Bird and a laserscanner. In addition, a hyperspectral camera will document melt pond depth and fraction. Moreover, a set of buoys deployed during previous campaigns will be revisited and new ones deployed. If possible, flight patterns will be coordinated with RV Polarstern activities.

Results from airborne surveys serve different scientific questions such as:

• a) Investigation of the thinning of sea ice due to a reduction of old multi-year ice
• b) Documentation of the decline in thickness in Fram Strait area: Together with information on sea ice trajectories and source areas, measurements provide inside into Arctic-wide mass balance changes of sea ice
• c) How is the sea ice export out of Fram Strait changing in summer when reliable satellite-based estimates are missing. Is the observed increase in area flux rates compensated by a decrease in sea ice thickness?
• d) How does the recirculation of Atlantic Water impact observed thickness gradients
• e) Investigation of melt pond fraction and depth development in summer over different ice types
• f) Investigation of sea ice deformation in summer and impact on the thickness distribution
• g) Upscale measurements made on board of RV Polarstern