000031002 001__ 31002
000031002 041__ $$aEnglish
000031002 100__ $$aKraaijenbrink, P.
000031002 245__ $$aSeasonal Surface Velocities of a Himalayan Glacier Derived by Automated Correlation of Unmanned Aerial Vehicle Imagery
000031002 260__ $$c2015
000031002 300__ $$adoi: 10.3189/2016AoG71A072
000031002 507__ $$aJoseph Michael Shea, ICIMOD staff, peerreviewed
000031002 511__ $$aCrysparticle
000031002 520__ $$aDebris-covered glaciers play an important role in the high-altitude water cycle in the Himalaya, yet their dynamics are poorly understood, partly because of the difficult fieldwork conditions. In this study we therefore deploy an unmanned aerial vehicle (UAV) three times (May 2013, October 2013 and May 2014) over the debris-covered Lirung Glacier in Nepal. The acquired data are processed into orthomosaics and elevation models by a Structure from Motion workflow, and seasonal surface velocity is derived using frequency cross-correlation. In order to obtain optimal surface velocity products, the effects of different input data and correlator configurations are evaluated, which reveals that the orthomosaic as input paired with moderate correlator settings provides the best results. The glacier has considerable spatial and seasonal differences in surface velocity, with maximum summer and winter velocities 6 and 2.5 m a–1, respectively, in the upper part of the tongue, while the lower part is nearly stagnant. It is hypothesized that the higher velocities during summer are caused by basal sliding due to increased lubrication of the bed. We conclude that UAVs have great potential to quantify seasonal and annual variations in flow and can help to further our understanding of debris-covered glaciers.
000031002 653__ $$aglaciers
000031002 653__ $$aglacier flow
000031002 653__ $$aglacier mapping
000031002 653__ $$aglaciological instruments and methods 
000031002 653__ $$aremote sensing
000031002 700__ $$aMeijer, S. W.
000031002 700__ $$aShea, J. M.
000031002 700__ $$aPellicciotti, F.
000031002 700__ $$aDe Jong, S. M.
000031002 700__ $$aImmerzeel, W. W.
000031002 773__ $$pAnnals of Glaciology
000031002 773__ $$v57 (71)
000031002 773__ $$a10.3189/2016AoG71A072
000031002 8564_ $$uhttp://www.ingentaconnect.com/content/igsoc/agl/pre-prints/content-ings_agl_71a072$$yExternal link
000031002 980__ $$aARTICLE