JGR-Atmos., 2008
In the tropics the atmospheric pressure variation throughout the day is dominated by a semidiurnal signal which is attributed to the downward propagation of the global-scale atmospheric tidal oscillation excited by solar heating of the ozone layer. The interaction of this wave with topography has been simulated by a very fine resolution version of a global general circulation model run on the JAMSTEC Earth Simulator. The model results for a measure of the amplitude of the semidiurnal pressure harmonic at each model grid box are shown in as the dots (top panel) for a 100km square box that includes the Big Island of
Hawaii. There is a reduction of amplitude with topographic height, and also a systematically smaller amplitude on the west side of the topography (black dots) than on the east side (red dots), an effect attributed to a shadowing of the downward and westward propagating wave
(bottom panel). The model results are compared with station observations from a network of sensors deployed at various sites on the Big
Island by Mauna Loa Observatory (blue numbers).