Atmospheric tides and oceanic tides are both large-scale periodic responses of fluid envelopes on a rotating planet driven by gravitational and thermal forcing, making the comparison a matter of basic geophysical definition.
The claim compares atmospheric tides to oceanic tides in terms of their underlying mechanisms. Both are global-scale tidal phenomena governed by fluid dynamics on a rotating globe (though oceanic tides are primarily gravitational, and atmospheric tides are primarily thermal/solar-driven, both share tidal wave mechanics and tidal forcing descriptions). This is a foundational physical concept about planetary atmospheres and oceans treated as common knowledge in geophysics, requiring no specific single citation to establish as a basic comparative definition.