Direct Observation of Near-sUrface Turbulent and Submeso Structures

DONUTSS-2010, DONUTSS-2011

Investigators

Adam Kennedy, Alex Smoot, Larry Mahrt, John Selker, Christoph Thomas (PI)

Sponsored by

Army Research Office, contracts W911NF-10-1-0361, W911NF-09-1-0271

Objective(s)

Data from the sensor network will lead to a direct evaluation of Taylor’s hypothesis and an improved understanding of all motions contributing to the dispersion and diffusion in weak-wind stable conditions. The sensor network is a unique combination of observational techniques including optical fiber distributed temperature sensing (DTS), acoustic remote sensing (SODAR), networks of sonic anemometers, and laser-illuminated flow visualization from fog releases.

Background

Weak-wind atmospheric transport near the surface remains one of the most poorly understood processes in the stable boundary layer.  Cases of weak flows in combination with moderate surface heterogeneity represent a substantial part of our environment, yet these conditions render conceptual frameworks, such as commonly applied similarity theories for turbulent fluxes, inadequate. Under these conditions, ground concentrations of contaminants can remain extremely high and the spatio-temporal dynamics of the plume difficult to predict.