Seeking an optimal algorithm for a new satellite-based Sea Ice Drift Climate Data Record : Motivations, plans and initial results from the ESA CCI Sea Ice project

The Sea Ice Essential Climate Variable (ECV) as defined by GCOS pertains of both sea ice concentration, thickness, and drift. Now in its second phase, the ESA CCI Sea Ice project is conducting the necessary research efforts to address sea ice drift.Accurate estimates of sea ice drift direction and magnitude are essential for quantification of the role of dynamic sea ice processes contributing to polar sea ice volume and ocean-atmosphere heat exchange. Error-characterised, long-term sea ice drift information are required for assessing the performance of climate simulations and further develops the physical parametrizations. Sea ice drift products are also required to locate regions of convergent and divergent ice motion across spatio-temporal scales from meters / hours to basins / years.The work in the CCI Sea Ice project includes defining metrics for assessing the accuracy of algorithms, selecting relevant satellite and “ground-truth” data, building the Round-Robin Data Package for testing the algorithms, and finally selection of the most promising algorithm(s) for processing of a new sea ice drift climate dataset. Specific efforts are dedicated to the definition of per-grid-cell uncertainties in the final product. This contribution reviews the motivation for the work, the plans for sea ice drift algorithms intercomparison and selection, and early results from our activity.