Recent Data Campaigns and Results from the Laser Vegetation Imaging Sensor (LVIS): An Airborne, Medium-Footprint, Full-Waveform, Swath Mapping Laser Altimeter System

The Laser Vegetation Imaging Sensor (LVIS) is an airborne, medium-sized footprint laser altimeter system. By digitally recording the shape of the returning laser pulse (waveform), LVIS provides a precise and accurate view of the vertical structure within each footprint/pixel including both the sub-canopy and canopy-top topography. Applications of LVIS data include biomass estimation for a wide variety of forest types, ground surface change detection for tectonic studies, mapping sea surface topography to assist in coastal hazard assessment, and hydrology studies utilizing sub-canopy topography in densely forested regions. Since 1998, LVIS data have been collected in various areas of New Hampshire, Maine, Massachusetts, California, Maryland, Panama and Costa Rica. The data calibration and geolocation processing system utilizes a formal Bayesian least-squares-estimation of pointing, ranging and timing parameters based on a batch reduction of altimeter range residuals. Data are released publicly on the LVIS website at http://lvis.gsfc.nasa.gov. Results show data precisions of <50 cm are routinely achieved in all forest types and <5 cm in bare ground conditions. Because of its unique capability to simultaneously map vegetation and sub-canopy ground topography, LVIS data can be used to assess the accuracy of other remote sensing systems. For example, ground and canopy top elevations generated by LVIS were used to assess the accuracy of Shuttle Radar Topography Mission (SRTM) elevations at study sites with different levels of relief and land cover type. Results showed that the mean vertical offset between the SRTM elevations and LVIS ground elevations varied with landcover type and study site location. Comparisons between LVIS and ICESat will also be presented.