Airborne lidar observations of canopy structure at the BOREAS tower flux sites

The Boreal Ecosystems Atmosphere Study (BOREAS) is a large-scale interdisciplinary experiment in the northern boreal forests of Canada focused on improving our understanding of the exchanges of radiative energy, sensible heat, water, CO₂ and trace gases between the boreal forest and the lower atmosphere. The spatial organization of forest canopies is an important biophysical parameter affecting these exchange processes. As a part of the BOREAS experiment, airborne lidar observations were acquired that characterize the vertical structure of the boreal forest and the topography of the underlying ground surface. The Scanning Lidar Imager of Canopies by Echo Recovery (SLICER) was used to acquire surface lidar transects across tower flux sites established within areas of relatively homogenous vegetation cover in the BOREAS Southern and Northern Study Areas (SSA and NSA). SLICER was deployed on the NASA Wallops Flight Facility C-130 during the BOREAS Summer 1996 Intensive Field Campaign. Nadir lidar transects were acquired simultaneously with Advanced Solid-state Array Spectreradiometer (ASAS) multi-angle imaging of the SSA and NSA tower sites. The SLICER transects extend outward from the towers for a distance of 10 to 30 km. The transects consist of narrow swaths nominally composed of contiguous, circular laser footprints each 8 m in diameter, with 5 footprints scanned cross-track