Quantification of sediment transport into Kongsfjorden due to the glacier melt dynamics of Austre Lovenbreen using terrestrial laser scanning
Résumé
Climate warming causes a decrease of glaciers in Svalbard. This results in sig-
nificant changes of the geomorphology of areas in glacier catchments where ice
and permafrost is melting. In particular the snout of the glacier melts drastically
and the water outflow of the glacier changes sometimes its direction. Sediment
and bed load transport forms new river beds in the moraine, and the sediments
involved are transported downstream into the fjords. In recent years terrestrial
laser scanning technology has developed significantly, so it is possible to mea-
sure the surface of a whole glacier catchment such as the Austre Lovenbreen in
high resolution just in a few days or even in one day. The measuring range of
6000 m combined with a very low beam divergence of the laser beam allows fast
and accurate measurements of an area of 4 km
2
just from one scan position. This
advances made it possible that we could track all surface changes via differenti-
ating digital surface models of the Austre Lovenbreen catchment using repeated
terrestrial laser scanning surveys in 20 cm resolution and with 10 cm accuracy.
In this work we show how the geomorphology of the scanned area changed in
just 2 years from 2016 to 2017. In this time frame the glacier outflow changed
its riverbed and significant amounts of sediments where transported through the
moraine into the fjord, which changed the morphology of the coastline as well.
Reflectance values of the laser allowed us to distinguish between snow, ice and
rock material. In our presentation we explain the methodology of the terrestrial
laser scanning surveys and discuss the results of how much material was removed
in the new river bed throughout the moraine, how much sediments where accu-
mulated at the coast line and how much of the material disappeared in the fjord.