Observation of a local gravity potential isosurface by airborne lidar of Lake Balaton, Hungary
- 1Vienna University of Technology, Department of Geodesy and Geoinformation; Gußhausstraße 27–29, 1040 Vienna, Austria
- 2Balaton Limnological Institute, Centre for Ecological Research, Hungarian Academy of Sciences; Klebelsberg Kuno út 3, 8237 Tihany, Hungary
- 3Eötvös Loránd University, Institute of Geography and Earth Science, Department of Geophysics and Space Science; Pázmány Péter Sétány 1/C, 1117 Budapest, Hungary
- 4Interdisziplinäres Ökologisches Zentrum, TU Bergakademie Freiberg, Leipziger Str. 29, 09599 Freiberg, Germany
- 5Ludwig Boltzmann Institute for Archaeological Prospection and Virtual Archaeology; Hohe Warte 38, 1190 Vienna, Austria
Abstract. Airborne lidar is a remote sensing method commonly used for mapping surface topography in high resolution. A water surface in hydrostatic equilibrium theoretically represents a gravity potential isosurface. Here we compare lidar-based ellipsoidal water surface height measurements all around the shore of a major lake with a local high-resolution quasi-geoid model. The ellipsoidal heights of the 87 km2 we sampled all around the shore of the 597 km2 lake surface vary by 0.8 m and strong spatial correlation with the quasi-geoid undulation was calculated (R2 = 0.91). After subtraction of the local geoid undulation from the measured ellipsoidal water surface heights, their variation was considerably reduced. Based on a network of water gauge measurements, dynamic water surface heights were also successfully corrected for. This demonstrates that the water surface heights of the lake were truly determined by the local gravity potential. We conclude that both the level of hydrostatic equilibrium of the lake and the accuracy of airborne lidar were sufficient for identifying the spatial variations of gravity potential.