Abstract
Knowledge of the variability of sea ice thickness is insufficient because the existing methods have some weaknesses. We applied Unmanned Aerial Vehicle with Structure from Motion (UAV-SfM) to estimate sea ice freeboard on the coast of Qaanaaq, NW Greenland. Three aerial photography methods were attempted to find an efficient way for surveying various sea ice using multi-rotor and fixed-wing UAVs. The UAV-SfM surveys with ground control points (GCP) layout generate a distribution map of freeboard with poor reproducibility. The main causes are the difficulty of dense GCP layout on various sea ice and change of GCP positions by tidal change. The UAV-SfM surveys without GCP (i.e., using precise geotagged image data) improved the operating efficiency in the harsh cold environment and generated a highly reproducible distribution map of freeboard. A fixed-wing UAV mounting camera equipped with a large image sensor is suitable for detecting small changes in the flat sea ice surface over a wide range. Further validation and technical improvement are required for practical application to sea ice thickness estimation.
