HW18 Advances in Remote Observation of Snow

IAHS (Hydrology)



24-Jun-2015, 08:30 - 10:00


 
Abstract content:

Airborne laser scanning: a basis for hydrological model studies in glacierized catchments

Lateral redistribution of snow has a strong effect on glacier mass balance and the seasonal regime of runoff in glacierized catchments. Therefore, the spatial and temporal snow depth distribution in the complex topography of glaciers and adjacent ice-free terrain was investigated using airborne laser scanning (ALS) data. ALS surveys in a catchment of approx. 36 km² including the glaciers Hintereisferner and Kesselwandferner (Ötztal Alps/Austria) allow to analyse the snow pattern for 5 different accumulation seasons since 2001. The data provide useful information on spatial variability of snow depth in relation to topographic features and ice cover. Simple linear regressions for snow depth with DEM-derived openness/shelteredness parameters were used to simulate the observed snow distribution for snow-hydrological modelling. The resulting simulated snow pattern was in good agreement with the ALS data. Small features of extreme accumulation, e.g. avalanches, could not be reproduced due to their inherently higher random component. A multi-objective model calibration study shows that the basin-wide SWE calculated from ALS-derived snow depth patterns is better suited than snow covered area to constrain model parameter ranges. The integration of ALS-derived SWE maps in the calibration and validation of physically-based snow-hydrological models improved the results not only for runoff simulations, but also for the long-term volume changes of the glaciers in the mountain region of the Ötztal Alps.

 
Author(s):
K. Helfricht1,2, J. Schöber2, F. Hanzer3,4, K. Schneider3, U. Strasser3,4, M. Lehning4,6, M. Kuhn5.
1Institute of Interdisciplinary Mountain Research, Austrian Acadamy of Sciences, Innsbruck, Austria.
2TIWAG, Tiroler Wasserkraft AG, Innsbruck, Austria.
3alpS, Centre for Climate Change Adaptation, Innsbruck, Austria.
4Institute for Snow and Avalanche Research SLF, Swiss Federal Institute for Forest- Snow and Landscape Research WSL, Davos, Switzerland.
5Institute of Meteorology and Geophysics, University of Innsbruck, Innsbruck, Austria.

 

Keywords:
airborne laser scanning     lidar     spatial distribution     snow     hydrological models     glacierized catchments