A different but also similar situation is seen further north
in the sub-equatorial region (Fig. 11). Here the AAIW salinity
minimum recorded by the float shows very good agreement
with the WOA mean field, particularly if the float time
series is shifted forward by 50–100 days. Since the float
moved eastward, a forward shift in time corresponds to an
eastward shift relative to the mean field, or a westward shift
of the mean field. Although this is not a data-rich region for
theWorld Ocean Atlas its data density is still acceptable, and
it appears that the observed shift is more likely the effect of
interannual movement of the salinity field than a bias in the
climatological mean field itself.