@Article{UrbazaevHHSOTDHUAS:2022:AsTeEl,
               author = "Urbazaev, Mikhail and Hess, Laura L. and Hancock, Steven and Sato, 
                         Luciane Yumie and Ometto, Jean Pierre Henry Balbaud and Thiel, 
                         Christian and Dubois, Cl{\'e}mence and Heckel, Kai and Urban, 
                         Marcel and Adam, Markus and Schmullius, Christiane",
          affiliation = "{Friedrich Schiller University Jena} and {University of 
                         California} and {University of Edinburgh} and {Instituto Nacional 
                         de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {German Aerospace Center (DLR)} 
                         and {Friedrich Schiller University Jena} and {Friedrich Schiller 
                         University Jena} and {Friedrich Schiller University Jena} and 
                         {Friedrich Schiller University Jena} and {Friedrich Schiller 
                         University Jena}",
                title = "Assessment of terrain elevation estimates from ICESat-2 and GEDI 
                         spaceborne LiDAR missions across different land cover and forest 
                         types",
              journal = "Science of Remote Sensing",
                 year = "2022",
               volume = "6",
                pages = "100067",
             keywords = "terrain elevation, accuracy assessment, GEDI, ICESat-2.",
             abstract = "Accurate measurements of terrain elevation are crucial for many 
                         ecological applications. In this study, we sought to assess new 
                         global three-dimensional Earth observation data acquired by the 
                         spaceborne Light Detection and Ranging (LiDAR) missions Ice, 
                         Cloud, and Land Elevation Satellite-2 (ICESat-2) and Global 
                         Ecosystem Dynamics Investigation (GEDI). For this, we examined the 
                         ATLAS/ICESat-2 L3A Land and Vegetation Height, version 5 (20 × 14 
                         m and 100 × 14 m segments) and the GEDI Level 2A Footprint 
                         Elevation and Height Metrics, version 2 (25 m circle). We 
                         conducted our analysis across four land cover classes (bare soil, 
                         herbaceous, forest, savanna), and six forest types (temperate 
                         broad-leaved, temperate needle-leaved, temperate mixed, tropical 
                         upland, tropical floodplain, and tropical secondary forest). For 
                         assessment of terrain elevation estimates from spaceborne LiDAR 
                         data we used high resolution airborne data. Our results indicate 
                         that both LiDAR missions provide accurate terrain elevation 
                         estimates across different land cover classes and forest types 
                         with mean error less than 1 m, except in tropical forests. 
                         However, using a GEDI algorithm with a lower signal end threshold 
                         (e.g., algorithm 5) can improve the accuracy of terrain elevation 
                         estimates for tropical upland forests. Specific environmental 
                         parameters (terrain slope, canopy height and canopy cover) and 
                         sensor parameters (GEDI degrade flags, terrain estimation 
                         algorithm; ICESat-2 number of terrain photons, terrain 
                         uncertainty) can be applied to improve the accuracy of ICESat-2 
                         and GEDI-based terrain estimates. Although the goodness-of-fit 
                         statistics from the two spaceborne LiDARs are not directly 
                         comparable since they possess different footprint sizes (100 × 14 
                         m segment or 20 × 14 m segment vs. 25 m circle), we observed 
                         similar trends on the impact of terrain slope, canopy cover and 
                         canopy height for both sensors. Terrain slope strongly impacts the 
                         accuracy of both ICESat-2 and GEDI terrain elevation estimates for 
                         both forested and non-forested areas. In the case of GEDI the 
                         impact of slope is, however, partly caused by horizontal 
                         geolocation error. Moreover, dense canopies (i.e., canopy cover 
                         higher than 90%) affect the accuracy of spaceborne LiDAR terrain 
                         estimates, while canopy height does not, when considering samples 
                         over flat terrains. Our analysis of the accuracy and precision of 
                         current versions of spaceborne LiDAR products for different 
                         vegetation types and environmental conditions provides insights on 
                         parameter selection and estimated uncertainty to inform users of 
                         these key global datasets.",
                  doi = "10.1016/j.srs.2022.100067",
                  url = "http://dx.doi.org/10.1016/j.srs.2022.100067",
                 issn = "2666-0172",
                label = "lattes: 1325667605623244 5 UrbazaevHHSOTDHUAS:2022:AsTeEl",
             language = "en",
           targetfile = "1-s2.0-S2666017222000293-main.pdf",
        urlaccessdate = "18 jun. 2024"
}