3.5 Ocean surface heat budget and ocean eddy transport in the South-East Pacific in a high-resolution coupled model (2009

3.5

Ocean surface heat budget and ocean eddy transport in the South-East Pacific in a high-resolution coupled model

Thomas Toniazzo, NCAS-Climate, University of Reading, Reading, United Kingdom; and C. R. Mechoso, L. Shaffrey, and J. Slingo

We present an analysis of the oceanic heat advection and its

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.