Hamilton, K., 1981: Latent heat release as a possible forcing mechanism for atmospheric tides. Monthly Weather Review, 109 (1), 3-17.
Abstract: The consequences of the hypothesis of Lindzen (1978) that latent heat release
may be a significant excitation mechanism for the semidiurnal atmospheric
tide are examined in some detail. Harmonic analysis of hourly rainfall data
from 79 tropical stations shows that the semidiurnal variation of rainfall
in the tropics is ~ 1 mm day-1 and has a phase near 0300 LST, just as Lindzen's theory requires. Analysis
of data at 85 midlatitude stations shows that the semidiurnal rainfall oscillation
there has its phase rather later (about 0600). The results of simple classical
tidal theory calculations which indicate that the geographical distribution
of the surface pressure response to latent heat forcing largely follows
that of the forcing itself are presented. This result is then used to suggest
a plausible explanation for the observed seasonal cycle of the semidiurnal
pressure oscillation in midlatitudes. Further calculations show that the
magnitude of the non-migrating components of the semidiurnal barometric
oscillation produced by latent heat excitation is not likely to be unrealistically
large. These calculations also suggest that Lindzen's hypothesis might be
verified by observing the phase of the semidiurnal pressure oscillation
in particularly arid regions.
The rainfall observations also show a strong diurnal (24 h) component in
the rainfall both in the tropics and in midlatitudes. The effects of latent
heat release on the 24 h tide are briefly discussed.