Aerial Mapping Yellowstone NP, USA

YNP 2003

Beginning in 2003, site-specific high-resolution aerial survey was conducted to map a status-quo of two rapidly changing hydrothermal areas in Yellowstone National Park: Ragged Hills in 2003 and West Nymph Creek Thermal Area in 2004. A 2 m³ helium balloon released to 50-80 m altitude served as low-cost platform easy to launch and retract on a highly flexible operating schedule. Pictures were taken with a Canon Powershot G5 with automatic interval shutter release, georeferenced by temporary marked ground control points and mosaicked to aerial maps with final ground resolutions of <2 cm. Despite significant variations in altitude, tilt, and orientation of the balloon-mounted camera and radiometric distortions, the mosaic´s final distortion was minimal (0.4 m +/-0.3 m). Absolute accuracy was approximately 0.5 m. Vegetation and hydrothermal feature classification, biological and redox zonations, water contents of mud pots, gas activity in hot springs as well as submarine sedimentation fans and hydrothermal vents could be outlined providing a highly detailed thermal inventory. Together with information from ground survey and basic chemistry analysis this thermal inventory was integrated into a public-domain digital atlas. In 2006, we went back to Ragged Hills and repeated the aerial survey with the goal of change detection (size, activity, chemistry of features)

3 master theses have been conducted within this project:

1. High resolution aerial and ground mapping of geothermal features in Ragged Hills, Yellowstone National Park (Juliane Becker, 2004) (publication: Freiberg Online Geoscience FOG Vol.11) and as peer-reviewed paper
2. Hydrogeochemical characterization and high resolution aerial mapping of geothermal features in West Nymph Creek Thermal Area, Yellowstone National Park (Baas Brimer, 2005) (publication: Freiberg Online Geoscience FOG Vol.13) and as peer-reviewed paper
3. High resolution aerial photography for change detection on geothermal features at Ragged Hills, Yellowstone National Park (Sabrina Scharf, 2008)