Diane Sarrazin

Publications (4)0 Total impact

• Conference Proceeding: Towards a Species-specific Description of Detailed Savanna Woody structure at Various Scales Using Imaging Spectroscopy and Waveform Lidar Sensing.

  Jan A. Aardt van, Jiaying Wu, Joseph McGlinchy, Diane Sarrazin, David Kelbe, Barend F. Erasmus, Renaud Mathieu, Konrad Wessels, Greg P. Asner, Dave Knapp, Ty Kennedy-Bowdoin
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  ABSTRACT: terrestrial ecosystems. Although such biomass can be assessed remotely using both passive and active sensing, characterization of detailed structure, important to conservation of structural biodiversity, remains elusive. Novel technologies, such as imaging spectroscopy and waveform light detection and ranging, have emerged as candidates for such assessment. We evaluated whether species-specific assessment of woody and foliar biomass, crown structure, and woody cover can be mapped at various scales using these remote sensing technologies in a set of related research efforts. Data were acquired via the Carnegie Airborne Observatory across a degraded-to-conserved landuse gradient in the savannas in and around the Kruger National Park, South Africa. A robust processing approach for waveform lidar data was first developed and included smoothing, deconvolution, and angle correction for off-nadir pulses. This was followed by a data fusion approach to species classification and waveform-based quantification of woody biomass and structure at the tree- to landscape scales. Classification results (53-74% overall accuracies) varied according to species and were constrained by phenological variation, while structural quantification was dependent on the management regime that dominated in either the conservation or rural subsistence farming regions. We were able to develop tree-, landuse-, and landscape-level models that described the structural variation in the system. More importantly, the detailed structural metrics can be used to steer management policy in these areas towards sustainable "natural thresholds" and subsistence farming, respectively. Results at various scales will be presented.
  34th International Symposium for Remote Sensing of the Environment, April 10-15, 2011, Sydney, NSW, Australia; 01/2011
• Conference Proceeding: Fusing waveform LIDAR and hyperspectral data for species-level structural assessment in savanna ecosystems

  Diane Sarrazin, Jan A. Aardt van, David W. Messinger, Greg P. Asner
  , Laser Radar Technology and Applications XV, Orlando, Florida, USA; 01/2010
• Conference Proceeding: Extracting Structural Land Cover Components using Small--footprint Waveform Lidar Data

  Joseph McGlinchy, Jan A. Aardt van, Harvey E. Rhody, John P. Kerekes, Emmett J. Ientilucci, Greg P. Asner, Dave Knapp, Renaud Mathieu, Ty Kennedy-Bowdoin, Barend F. Erasmus, Konrad Wessels, Izak P. Smit, Jiaying Wu, Diane Sarrazin
  Proceedings of 2010 IEEE International Geoscience & Remote Sensing Symposium, IGARSS, Honolulu, Hawaii, USA; 01/2010
• Source

  Available from: Jan Andreas van Aardt

  Conference Proceeding: Extracting strctural land cover components using small-footprint waveform lidar data.

  Joseph McGlinchy, Jan van Aardt, Harvey Rhody, John Kerekesa, Emmett Ientiluci, Gregory Asner, David Knapp, Renaud Mathieu, Ty Kennedy-Bowdoin, Barend Erasmus, Konrad J. Wessels, Izak Smit, Jiaying Wu, Diane Sarrazin
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  ABSTRACT: Previous work has shown the ability of waveform LiDAR sensors to accurately describe various land cover types [1] and biomass estimates made in the field [2]. What is lacking, however, is a way to describe the different structural components that are embedded in the digitized backscattered energy from the LiDAR pulse. This study aims to extract structural components from waveform LiDAR data in terms of woody, herbaceous, and bare ground components from data collected over a savanna environment in and around Kruger National Park (KNP), South Africa. These components are comprised of metrics extracted from the waveforms and validated using biomass measurements made in field plots. Different size windows around plot centers, 3 × 3 pixels and 9 × 9 pixels (resulting in 1.5m and 4.5 m footprint, respectively), were used to examine scale effects of larger footprints. It was found that composite waveforms resembling plot sizes (9 × 9) most often are able to describe more than 80% of the woody biomass variability across the entire study site, and individually for two of the three land uses within the area. However, the herbaceous component of the waveform did not correlate well with the field measurements, while the bare ground component was verified visually in a side-by-side comparison with optical imagery.
  IEEE International Geoscience & Remote Sensing Symposium, IGARSS 2010, July 25-30, 2010, Honolulu, Hawaii, USA, Proceedings; 01/2010