Sea surface height determination in the Arctic Ocean from ERS altimetry

Accurate sea surface height measurements have been extracted from ERS altimeter data in sea ice–covered regions for the first time. The data have been used to construct a mean sea surface of the Arctic Ocean between the latitudes of 60°N and 81.5°N based on 4 years of ERS‐2 data. An RMS value for the crossover differences of mean sea surface profiles of 4.2 cm was observed in the ice‐covered Canada Basin, compared with 3.8 cm in the ice‐free Greenland‐Iceland‐Norwegian Seas. Comparisons are made with an existing global mean sea surface (OSUMSS95), highlighting significant differences between the two surfaces in permanently ice‐covered seas. In addition, we present the first altimeter‐derived sea surface height variability map of the Arctic Ocean. Comparisons with a high‐resolution coupled ocean–sea ice general circulation model reveal a good qualitative agreement in the spatial distribution of variability. Quantitatively, we found that the observed variability was on average a factor of 3–4 greater than model predictions.