Isolating the source of non-tidal oceanographic noise in seafloor
pressure data is critical for improving the use of these data for
seafloor geodetic applications. Residuals between nearby bottom pressure
records have typically been used to remove the non-tidal components, as
these are largely common-mode. To evaluate the similarities between
pairs of observed bottom pressure records at a range of water depths, we
calculate the standard deviations of the time series of residuals
between data from all site pairs, recorded during a recent experiment
offshore New Zealand. Similar to a recent study offshore Cascadia, we
find that the magnitude of the standard deviation depends more on
relative water depth than the distance between sites. This confirms that
non-tidal components are more similar along isobaths even if the
distance between sites is large. We show that the depth range varies
with the depth of the deeper site of the pairs under restrictions.