Kennedy Siding 2007 - Canopy Turbulence Experiment

by Andreas Christen(1) and Michael Novak(2)
with scientific contributions from Andrew T. Black(2), Mathew Brown(2) and Zoran Nesic(2).

(1) University of British Columbia, Department of Geography, Vancouver, Canada.
(2) University of British Columbia, Faculty of Land and Food Systems, Vancouver, Canada.

In this field experiment we measured vertical profiles of turbulence statistics in and above a uniform and sparse Lodgepole Pine Stand in Central British Columbia, Canada. In particular we focus on the budgets of turbulent kinetic energy and sensible heat and how the low canopy density affects those in comparison to measurements in denser forests.

The density of vegetation stands significantly controls turbulent exchange of momentum, heat and mass. Interestingly, most full-scale plant canopy studies done so far focussed on dense canopies. Less information is available for sparse canopies even though they form a significant part of the global land surfaces - in particular in the boreal zone. The current experiment was run at the long-term 'Kennedy Siding' tower 60km South of MacKenzie in Central British Columbia, Canada. The stand surrounding the 'Kennedy SIding' tower has a mean canopy height of h = 16 m with an open trunk space. At the time of the experiment, the canopy had a low canopy cover of only 24.3% and a Leaf Area Index of 1.38.

Data was sampled using a vertical array of ultrasonic anemometers. Eight Campbell Scientific CSAT-3 ultrasonic anemometer thermometers were simultaneously operated at different heights (z/h = 0.16, 0.44, 0.68, 0.87,1.06, 1.25, 1.56, and 1.96). This set-up was run for four weeks between August 22 and September 17, 2007.

These measurements were complemented with a profile of fine-wire thermocouples to retrieve an accurate vertical profile of mean temperatures. Data from all levels and sensors were synchronized at 10 Hz.

Upcoming Publications on the Kennedy Siding 2007 campaign

Christen A., Novak M., Black T. A., Brown M. (2008): 'The budgets of turbulent kinetic energy and sensible heat flux within and above a sparse Lodgepole Pine stand', 18th Conference on Atmospheric BioGeosciences / 28th Conference on Agricultural and Forest Meteorology, April 27 - May 2, 2008.

Christen A., Novak M. (2008): 'Higher-order statistics of the turbulent flow in a sparse Lodgepole Pine canopy', AMS 18th Symposium on Boundary Layers and Turbulence, June 9 - 13, 2008.


The vertical profile of anemometers in the Lodgepole Pine stand in August 2007.


Photo Gallery Kennedy Siding 2007 Gallery


Access plots showing 10 Hz data or 30-min statistics for the full experiment period.

Browse through available database entries.


This research activity has been made possible by:


NSERC Discovery Grants #342029-07 (Christen) and # (Novak) and an NSERC RTI #344541-07 (Christen). The long-term infrastructure tower is part of a CFCAS project on carbon exchange (Black).

We also thank Andrew Sauter and Jonathan Bau for their excellent support in the lab and/or the field.