Sensitivity assessment of morphometric parameters of monogenetic volcanic landforms with global free DEMs

Abstract

Improvements in the resolution of Digital Elevation Model (DEM) have greatly facilitated the research of small to moderate landforms such as dunes, landslides/rockfalls, moraines/drumlins and monogenetic volcanoes. Global free 30 m DEMs including data derived from Shuttle Radar Topography Mission (SRTM), Advanced Land Observing Satellite (ALOS) World 3D 30 m (AW3D30), and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER GDEM) are widely used. However, little is known of whether they can be used effectively in monogenetic volcanology. The focus of this study is to explore the accuracy and potential application of global free SRTM 30 m and AW3D30, as well as ASTER GDEM (previously studied) in monogenetic volcanic fields. We compared SRTM and AW3D30 with four reference higher-resolution DEM dataset, including National Elevation Dataset (NED) 10 m in Uinkaret Volcanic Field (UVF) (United States), WorldDEM 12 m in Longgang Volcanic Field (LVF) (China), Contour Line Based DEM (CLBD) 1 m in Jeju Island Volcanic Field (JIVF) (South Korea), and Light Detection And Ranging (LiDAR) 1 m in Lunar Crater Volcanic Field (LCVF) (United States). The results indicate that AW3D30 has higher accuracy than SRTM in all comparisons including elevation, slope angle and morphological parameters of scoria cones and associated lava flows. However, the accuracy of AW3D30 is almost the same as that of SRTM in that it is affected by slope angle, volume of volcanic edifices, and morphological features of scoria cones. In general, slope angle has a significant effect on the elevation and slope angle errors, which is consistent with previous studies. When the volume of the scoria cones is >5 × 106 m3 and the volume of the lava flows is above 10 × 106 m3, the average errors of their morphological parameters generated by SRTM and AW3D30 do not exceed 16.3 %. The morphological features are classified as crater (the central depression within a scoria cone), crater rim (the top 15 % of the highest elevations), lower flank (the lowest 15 % of the elevations), and middle flank (the remainder of a scoria cone). The area near the crater rim is often the area where larger errors occur, especially on the crater side. The middle and lower flank areas have milder errors. Additionally, the simulation of pre-eruptive surfaces should take into account the effects of certain factors such as roughness and flatness when calculating the volume. Overall, AW3D30 has the best potential in monogenetic volcano studies, followed by SRTM and ASTER GDEM.