A comparison between the World Ocean Atlas and Hydrobase climatology

Abstract

The gridded 1/4° World Ocean Atlas (WOA, Boyer and Levitus, 1998) is compared with the 1° WOA (Levitus et al., 1994) over the North Atlantic Ocean. The temperature and salinity fields from both the 1/4° and 1° WOA are projected on two isopycnal surfaces and compared with the Hydrobase climatology (Lozier et al., 1995). Geostrophic current maps diagnosed from hydrographic temperature and salinity are also presented. Results show that the 1/4° WOA, with a smaller smoothing radius, greatly improves the 1° WOA in several important aspects. In particular, sharp frontal features associated with the western boundary current which are absent in the 1° WOA are apparent in the 1/4° WOA. The 1/4° WOA describes similar small-scale mid-depth recirculation gyres reported by Lozier (1997) based on Hydrobase. However, 'artifacts' in the property fields created by the isobaric averaging are still evident in the 1/4° WOA.