Diurnal oscillations in atmospheric pressure at twenty‐five small oceanic islands

The diurnal oscillation in atmospheric surface pressure—the S1(p) tide—is estimated at 25 oceanic stations. The estimated mean amplitudes and phases are compared to two theoretical predictions of the migrating S1 component recently computed by Braswell and Lindzen and to the older wavenumber‐1 decomposition of Haurwitz and Cowley. The new S1 amplitudes are weaker than the Haurwitz‐Cowley amplitudes everywhere, suggesting that their model may have been unduly influenced by nonmigrating components from continental stations. The observations show best agreement with a theoretical model having 25 W m−2 additional atmospheric energy absorption relative to that inferred from general circulation models. Stations polewards of the S1 critical latitude are somewhat anomalous.