Dokument-ID Dokumenttyp Verfasser/Autoren Herausgeber Haupttitel Abstract Auflage Verlagsort Verlag Erscheinungsjahr Seitenzahl Schriftenreihe Titel Schriftenreihe Bandzahl ISBN Quelle der Hochschulschrift Konferenzname Quelle:Titel Quelle:Jahrgang Quelle:Heftnummer Quelle:Erste Seite Quelle:Letzte Seite URN DOI Abteilungen OPUS4-36297 Wissenschaftlicher Artikel Scherler, Dirk; Strecker, Manfred Large surface velocity fluctuations of Biafo Glacier, central Karakoram, at high spatial and temporal resolution from optical satellite images Despite global warming and unlike their Himalayan neighbours, glaciers in the Karakoram mountains do not show signs of significant retreat. Here we report high velocity variations of Biafo Glacier, central Karakoram, which occurred between 2001 and 2009 and which indicate considerable dynamics in its flow behaviour. We have generated a dense time series of glacier surface velocities, based on cross-correlation of optical satellite images, which clearly shows seasonal and interannual velocity variations, reaching 50% in some places. The interannual velocity variations resemble the passing of a broad wave of high velocities, with peak velocities during 2005 and some diffusion down-glacier over a period of at least 4 years. High interannual velocity variations are also observed at other glaciers in the vicinity, suggesting a common cause, although these appear to partly comprise longer acceleration phases. Analysis of weather station data provides some indications of meteorological conditions that could have promoted sustained sliding events during this period, but this does not explain the wave-like nature of the acceleration at Biafo Glacier, and the regular, protracted velocity changes. Cambridge International Glaciological Society 2012 12 Journal of glaciology 58 209 569 580 10.3189/2012JoG11J096 Institut für Geowissenschaften OPUS4-36282 Wissenschaftlicher Artikel Wulf, Hendrik; Bookhagen, Bodo; Scherler, Dirk Climatic and geologic controls on suspended sediment flux in the Sutlej River Valley, western Himalaya The sediment flux through Himalayan rivers directly impacts water quality and is important for sustaining agriculture as well as maintaining drinking-water and hydropower generation. Despite the recent increase in demand for these resources, little is known about the triggers and sources of extreme sediment flux events, which lower water quality and account for extensive hydropower reservoir filling and turbine abrasion. Here, we present a comprehensive analysis of the spatiotemporal trends in suspended sediment flux based on daily data during the past decade (2001-2009) from four sites along the Sutlej River and from four of its main tributaries. In conjunction with satellite data depicting rainfall and snow cover, air temperature and earthquake records, and field observations, we infer climatic and geologic controls of peak suspended sediment concentration (SSC) events. Our study identifies three key findings: First, peak SSC events (a parts per thousand yen 99th SSC percentile) coincide frequently (57-80%) with heavy rainstorms and account for about 30% of the suspended sediment flux in the semi-arid to arid interior of the orogen. Second, we observe an increase of suspended sediment flux from the Tibetan Plateau to the Himalayan Front at mean annual timescales. This sediment-flux gradient suggests that averaged, modern erosion in the western Himalaya is most pronounced at frontal regions, which are characterized by high monsoonal rainfall and thick soil cover. Third, in seven of eight catchments, we find an anticlockwise hysteresis loop of annual sediment flux variations with respect to river discharge, which appears to be related to enhanced glacial sediment evacuation during late summer. Our analysis emphasizes the importance of unconsolidated sediments in the high-elevation sector that can easily be mobilized by hydrometeorological events and higher glacial-meltwater contributions. In future climate change scenarios, including continuous glacial retreat and more frequent monsoonal rainstorms across the Himalaya, we expect an increase in peak SSC events, which will decrease the water quality and impact hydropower generation. Göttingen Copernicus 2012 25 Hydrology and earth system sciences : HESS 16 7 2193 2217 10.5194/hess-16-2193-2012 Institut für Geowissenschaften