Before we address the AAIW variability seen in the Argo floats in detail it is necessary to understand the features of the underlying climatological mean field seen in the WOA data. AAIW in the South Pacific Ocean is supplied from two different sources with slightly different minimum salinities (Tomczak and Godfrey, 2003). The two AAIW varieties meet in the New Zealand region, which leads to water movement at 700–1100m depth across strong salinity gradients (Fig. 5) in the western South Pacific