Turbulent bursts in the atmosphere

Although the spectral description of turbulent flows has provided some valuable clues about pollutant dispersion in the atmosphere, there has been a growing feeling that such a description may be too limited for providing an understanding of the dynamics as detailed phase information is discarded. Recent work on the coherent structures discovered in a wide variety of turbulent shear flows raises the question whether an alternative description of turbulent flow might be useful. This issue is considered here, and we describe how far one may go in an 'episodic' description of turbulent motion. In particular, the results of a detailed analysis of motion in a nearly-neutral atmospheric boundary layer, seeking an identification and characterization of momentum and flux events, and the associated burstiness of the motion, are surveyed