Abstract
This paper presents the results of a detailed study of the diurnal and semidiurnal pressure variations at the surface across the continental United States. Using a larger dataset than preceding studies and a variety of analysis approaches, the spatial and temporal variations in the diurnal and semidiurnal components of station and sea level pressure are described, and the influence of current pressure reduction techniques on the characteristics of sea level pressure is evaluated. It is shown that the temperature-averaging scheme currently used in sea level pressure reduction creates a bogus semidiurnal signal in sea level pressure over high terrain. This paper also describes the summertime mesoscale evolution of station pressure over the northeast United States and presents 3-h pressure-change maps for the continental United States during the summer and winter seasons.
