QUASI-STATIONARY WAVES OBSERVED IN AEROSOL DIFFUSION TRIALS CONDUCTED IN A COASTAL AREA

Abstract

In a series of diffusion trials conducted by the U.S. Army Chemical Corps in 1955 and 1956, there were strong departures from the model, originally proposed by Sutton, in which the logarithm of the crosswind integrated dosage varies linearly with the logarithm of the downwind distance. These departures cannot be reasonably explained in terms of ordinary meteorological variables. A hypothesis that they are due to quasi-stationary waves in the flow is shown to be supported (a) by systematic, in-phase departures from linearity exhibited by the three tracer materials released in each trial, (b) by the coordinated wave-like motion of the azimuth of maximum recovery, (c) by the fact that the trials with the greatest departures from linearity also exhibit the most rapid loss of material from the sampling plane. The waves are probably induced by a sharp drop-off of the terrain to the sea approximately two miles upwind of the sampling grid.