Short term variations of tracer transit speed on alpine glaciers 1Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie (VAW), ETH Zürich, 8092 Zürich, Switzerland
23 Sep 2010
2Department of Geosciences, University of Oslo, Oslo, Norway
*Invited contribution by M. A. Werder, recipient of the EGU Young Scientists Outstanding Poster Paper Award 2009.
Received: 20 April 2010 – Published in The Cryosphere Discuss.: 18 May 2010 Abstract. We first present the results of a series of tracer experiments
conducted on an alpine glacier (Gornergletscher, Switzerland) over a
diurnal discharge cycle. For these injections, a moulin was used
into which an ice marginal lake was draining, providing a relatively
constant discharge. The measured tracer transit speeds show two
diurnal maxima and minima. These findings are qualitatively
different to existing observations from two series of injections
conducted at Unteraargletscher (Switzerland) using a moulin fed by
supraglacial meltwater having a high diurnal variability, which
displayed one diurnal maximum and minimum.
Revised: 21 August 2010 – Accepted: 03 September 2010 – Published: 23 September 2010
We then develop and use a simple two-component model of the glacier
drainage system, comprising a moulin and a channel element, to
simulate the measured transit speeds for all three injection series.
The model successfully reproduces all the observations and shows
that the same underlying processes can produce the qualitatively
different behaviour depending on the different moulin input
discharge regimes. Using the model, we assess the relative
importance of the different measurement quantities, show that
frequent measurements of moulin input discharge are indispensable
and propose an experiment design to monitor the development of the
drainage system over several weeks.
Citation: Werder, M. A., Schuler, T. V., and Funk, M.: Short term variations of tracer transit speed on alpine glaciers, The Cryosphere, 4, 381-396, doi:10.5194/tc-4-381-2010, 2010.