Assessment of airborne LIDAR for snowpack depth modeling

Resumen

The Institut Geològic
de Catalunya (IGC) and the Institut Cartogràfic de Catalunya (ICC)
have begun a joint project to model snowpack depth distribution in
the Núria valley (a 38 km² basin located in the Eastern Pyrenees) in
order to evaluate water reserves in mountain watersheds . The
evaluation was based on a remote sensing airborne LIDAR survey and
validated with field–work calculations. Previous studies have
applied geostatistical techniques to extrapolate sparse point data
obtained from costly field–work campaigns. Despite being a recently
developed technique, LIDAR has become a useful method in snow
sciences as it produces dense point data and covers wide areas. The
new methodology presented here combines LIDAR data with field–work,
the use of geographical information systems (GIS) and the stepwise
regression tree (SRT), as an extrapolation technique. These methods
have allowed us to map snowpack depth distribution in high spatial
resolution. Extrapolation was necessary because raw LIDAR data was
only obtained from part of the study area in order to minimise
costs. Promising results show high correlation between LIDAR data
and field data, validating the use of airborne laser altimetry to
estimate snow depth. Moreover, differences of total snow volume
calculated from modeled snowpack distribution and total volume from
LIDAR data differ by only 1%.