Statement of Purpose:
The Ice, Cloud and Land Elevation Satellite (ICESat) 2 is scheduled for launch in 2017 and one of its overall science objectives will be to measure vegetation heights, which can be used to estimate and monitor aboveground biomass (AGB) over large spatial scales. The data set used for this study will serve to develop a methodology for utilizing data collected by ICESat-2 that will be on a five-year mission from 2017, for mapping forest canopy heights and estimating above-ground forest biomass (AGB). Using existing airborne lidar data (ALS) for Sam Houston National Forest (SHNF) and known ICESat-2 beam locations, ICESat-2 footprints were generated along beam locations and photon-counting lidar (PCL) data were then simulated from discrete return lidar points within each footprint. Simulated photon data will be displayed as a vegetation height profile alongside corresponding ALS data for SHNF. The data will facilitate the direct retrieval of tree heights and estimation of AGB using simple linear regression using previously estimated AGB for SHNF from a biomass map generated with ALS data and simulated PCL height metrics along ICESat-2 tracks. These can be used to measure forest parameters and in extension, estimate forest carbon for climate change initiatives. While ICESat-2 will not be launched until 2017, it is essential to understand how the data can be used and be prepared to have a methodology in place to use future ICESat 2 data as soon as it becomes available.
Description of Data Sets:
The data set consists of simulated photon-counting lidar data generated using a photon simulator developed by Dr. Amy Neuenschwander from Applied Research Laboratories at University of Texas, Austin. The data was simulated from existing airborne lidar data (ALS) for Sam Houston National Forest (SHNF) acquired by Dr. Sorin Popescu from the Department of Ecosystem Science and Management, Texas A&M University and along known ICESat-2 beam locations. ICESat-2 tracks consist of footprints measuring approximately 14 m in diameter and with 70 cm along-track intervals. Between 2 to 3 photos were generated for each footprint and simulated photons for approximately 64km of tracks along SHNF were analyzed for this study.