Persistent artifacts in the NSIDC ice motion data set and their implications for analysis

Abstract

AbstractIn this study we evaluate weekly Equal‐Area Scalable Earth Grid (EASE‐Grid) sea ice velocities released by the National Snow and Ice Data Centre (NSIDC). We identify persistent Eulerian and Lagrangian features that arise solely as an artifact of the method used in the incorporation of buoy data. This, in turn, significantly impacts calculation of sea ice motion gradients, including divergence, convergence, and shear. Our numerical experiments and comparison with observations further demonstrate the impact of these artificial features on climatological assessments, including age‐of‐ice studies. In particular, we find that age‐of‐ice studies using this data set significantly underestimate multiyear ice extent by an average of 0.8 × 106 km2 in the month of March.