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

[HTT14-02] Observation of Diurnal Ground Surface Changes Due to Freeze-Thaw Action by RTK-UAV

★Invited Papers

*Yasutaka Nakata¹, Masato Hayamizu², Nobuo Ishiyama², Hiroyuki Torita² (1.Kyoto Prefectural University Graduate School of Life and Environmental Sciences Division of Environmental Sciences, 2.Hokkaido Research Organization Forest Research Institute Forest Environment Division)

Keywords:RTK-UAV, Freeze-thaw action, Landslide, Thermal imagery, Generalized linear model

Ground surface changes caused by freeze-thaw action affect agriculture and forestry, as well as artificial structures such as roads. In this study, an area is examined in which reforestation is urgently needed but the growth of naturally restored seedlings and planted trees is impaired by freeze-thaw action. Thus, a method of measuring freeze-thaw-induced ground surface changes and mitigating their negative impacts is needed. Real-time kinematic unmanned aerial vehicle and structure-from-motion multiview stereophotogrammetry are used on slope-failure sites in forest areas to observe the ground surface changes caused by freeze-thaw action over a wide area, in a non-destructive manner. The slope characteristics influencing the ground-surface changes were examined, and it was confirmed that it is possible to observe minute topographical changes of less than ±5 cm resulting from freeze-thaw action. Statistical models show that the amount of freeze-thaw action is mostly linked to the cumulative solar radiation, daily ground-surface temperature range, and topographic-wetness index, which influence the microscale dynamics of the ground surface. The proposed method will be useful for future quantitative assessments of ground-surface conditions. Further, efficient reforestation could be implemented by considering the effects of the factors identified on the amount of freeze-thaw action.