[H-TT14] HIGH-DEFINITION TOPOGRAPHIC SURFACE DATA FOR CONNECTIVITY IN THE ANTHROPOCENE

[HTT14-03] Application of High-Definition Multilayered Earth Surface Data for geoecological surveys in intertidal zones

*Satomi Imagawa¹, Yuichi S Hayakawa² (1.Graduate School of Environmental Science, Hokkaido University, 2.Faculty of Environmental Earth Science, Hokkaido University)

Keywords:HiMESD, algal distribution, intertidal zone, microtopography, photogrammetry, iPhone-LiDAR

Intertidal zones along coasts are an active boundary between land and sea affected by dynamic changes in tide levels. In the intertidal zones, temperature, salinity, and pH of sea water are altered by changes in the tidal range, and a variety of organisms including seaweeds inhabit adapting the degree of alteration of the environmental factors. These environmental conditions are also related to topographic and wave factors. While the size and depth of ocean basins, the range of ocean currents, and tidal ranges influences the coastal wave characteristics, microtopography in rocky coast such as tide pools, notches in cliffs, and rock surface roughness, are crucial for forming the variety of environmental conditions for the inhabitant organisms. Acquisition of detailed data including their spatiotemporal changes is essential for understanding these fine-scale environmental conditions. Therefore, efficient measurement methods are required forsurveys in the intertidal zones, despite their accessibility issues. In the conventionalseaweed bed surveys, however, measurements along transects have required enormous labor and time, while wide-range surface data from satellite imagery, whose resolution is up to ca. 50 cm, has been considered insufficient for confirming the presence of small seaweed vegetation. Here we utilize uncrewed aerial vehicles (UAVs) equipped with multi-band, thermal, and light detection and ranging (LiDAR) sensors to confirm the extent of changes in seaweed vegetation, microtopographic elements, and the change of surface temperatures within the intertidal zones. We also use a pole-mounted camera and Structure-from-Motion Multi-View Stereo (SfM-MVS) photogrammetry, as well as smartphone-borne mobile LiDAR, for identifying smaller features. We then evaluate the effectiveness of these new methods in comparison to the conventional methods, and discuss the suitability of the measurement methods according to the targets and necessary information, together with their potential for the future studies.