The Arctic Ocean (AO) is a hotspot of climate change impacts. These are manifested in decreasing sea ice cover, rising sea level, increasing sea surface temperatures, and changes in ocean circulation. Accurate observations of these changes over decades-long time periods is a prerequisite for understanding the underlying dynamic processes, predicting future developments, and taking appropriate adaptation measures. In this context, satellite altimetry provides valuable information on changes in sea level and geostrophic ocean surface currents. However, under the challenging environmental conditions in the Arctic Ocean, meaningful results rely on careful pre-processing of radar measurements and appropriate handling of missing or biased signals due to sea ice cover and in coastal areas.

AROCCIE (Arctic Ocean Surface Circulation in a Changing Climate and its Possible Impact on Europe) is a joint project of DGFI-TUM and DTU Space. It targets on the creation of refined methods and algorithms to generate improved information on geostrophic surface currents in the AO based on long-term sea level changes from satellite altimetry measurements in combination with data from other sensors and models. In this context, the project will also improve the Arctic marine gravity field and evaluate the impact of wind and tides. Beside improvements in the data analysis of classical altimetry, the project will also investigate benefits by incorporating data from the CryoSat-2 SARIn and SWOT (Surface Water and Ocean Topography) missions. The generated AO surface circulation data set will be analysed with respect to signatures of climate change. In particular, we will study changes in direction and strength of the currents over the last two decades and exploit their possible impacts on Europe.