  Normal-mode coupling is a technique applied to probe the solar interior using
surface observations of oscillations. The technique, which is straightforward
to implement, makes more use of the seismic information in the wavefield than
other comparable local imaging techniques and therefore has the potential to
significantly improve current capabilities. Here, we examine supergranulation
power spectra using mode-coupling analyses of intermediate-to-high-degree modes
by invoking a Cartesian-geometric description of wave propagation under the
assumption that the localized patches are much smaller in size than the solar
radius. We extract the supergranular power spectrum and compare the results
with prior helioseismic studies. Measurements of the dispersion relation and
life times of supergranulation, obtained using near surface modes (f and
p$_1$), are in accord with the literature. We show that the cross-coupling
between the p$_2$ and p$_3$ acoustic modes, which are capable of probing
greater depths, are also sensitive to supergranulation.
