variability in the Southeastern tropical Pacific as simulated by the

global coupled model HiGEM. The model produces a realistic

climatology for this region and it represents a temperature advection

field arising from transient small-scale ($<450$ km) features which is consistent with estimates based on long-term observational data. The

eddy advection field is characterised by very persistent ($>4$

months) structures, which significantly affect the oceanic heat budget

on scales of several hundreds of km and over periods of over a year.

While several different mechanisms may be responsible, including the

ENSO and anomalous ventilation from the extratropics, a significant

component of this strongly rectifying anomalous advection field is

likely to be caused by sharp large-scale, climatological salinity

gradients associated with a fresh intrusion of mid-latitude water

which penetrates north-westward beneath the tropical thermocline.