A 1/3 {$^\circ$} resolution model of the tropical Pacific Ocean is
used to investigate eddy energetics associated with tropical
instability waves (TIWs) in the equatorial Pacific Ocean from 1996
to 2000. The geographical dependence of the balance of the perturbation
energy equation is explored, and the sensitivity of the results to
the wind forcing and the model's resolution is investigated.
Eddy kinetic energy reaches large values in fall 1998
during La Nina and TIWs are absent during El Nino (spring 1997 to
spring 1998). At 135$^{\circ}$W, the large mean to eddy kinetic
energy conversion is dominated by $\overline{u'v'} \partial
U/\partial y$, $\overline{v'v'}\partial V/\partial y$ and
$\overline{u'w'}\partial U/\partial z$. All those terms are
subject to seasonal and interannual variability. Baroclinic instability also
provides energy to the TIWs between 1$^{\circ}$ and 4$^{\circ}$N through the
conversion of eddy potential to eddy kinetic energy.
Largest eddy energy production are observed in surface at 4$^{\circ}$N within
the anticyclonic shear between the SEC and the NECC, where the eddy kinetic energy
is maximum. $\overline{u'v'}\partial U/\partial y$ is maximum just north of the equator
at about 50\,m in fall 1996 while it is maximum at the surface
in fall 1998 and fall 1999, suggesting that the TIWs derive their energy
from the EUC-SEC shear in 1996 and from the shear within the SEC in 1998
and 1999. $\overline{v'v'}\partial V/\partial y$ and $\overline{u'w'}\partial
U/\partial z$, which generally tend to weaken the waves just to the north
of the equator, are also subject to interannual variability and their combination
with $\overline{u'v'}\partial U/\partial y$ lead to weaker TIWs in fall
1996 compared to fall 1998 and 1999.