Satellite-derived interannual ocean bottom pressure variability and its relation to sea level

Knowledge of the relationship between bottom pressure pb and sea level ζ is important for understanding ocean circulation and climate. We use recent Gravity Recovery and Climate Experiment (GRACE) Release-05 data along with altimetry toinvestigate the relationship between ζ and pb over long periods (> 1 yr) and large scales (> 750 km). Elevated pb signals are observed over deep extratropical regions (e.g., Southern Ocean basins) and shallow or semi-enclosed areas (e.g., Indonesian and Nordic seas). In these places, considerable ζ variance is explained by pb variance. Correlation between ζ and pb is significant in many regions, including instances of significant negative correlation suggestive of active baroclinic processes. Results exemplify the good quality of GRACE Release-05 data and demonstrate that contemporary regional ζ variability cannot always be interpreted in terms of steric changes alone.