REAL Observations of Turbulent Coherent Structures

The Glossary of Meteorology defines coherent structures as "Three-dimensional regions in a turbulent flow with characteristic structures and lifetimes in terms of velocity, temperature, etc., that are significantly larger or longer-lived than the smallest local scales."

Turbulent coherent structures in the clear atmospheric surface layer are sometimes revealed by REAL. This is possible when atmospheric aerosol is not homogeneous and servers as a tracer of the circulations. We first noticed the REAL was capable of seeing fields of coherent structures while deployed at the U.S. Army's Dugway Proving Ground, in Dugway, Utah, in 2005. In the following image the aerosol backscatter data has been high-pass median filtered to remove effects of attenuation and shot-to-shot laser pulse energy variations. Observations like these inspired Dr. Mayor to propose deploying the REAL at the 2007 Canopy Horizontal Array Turbulence Study (CHATS) to search for more turbulent coherent structures.

A 70-minute time-lapse animation of the above is available upon request.