Long-term kinematic monitoring of glacier surface deformation using single-frequency GNSS receivers

Overview

The behavior of a glacier is characterized by long-term processes (e.g. ablation) and short-term events (e.g. Glacial Lake Outburst Floods (GLOFs)). Depending on the triggering forces the dynamic response of the glacier can be, e.g. an ice surface uplift, a change in flow direction or a change in flow velocity. The aim of this study is the kinematic monitoring of the glacier surface using a network of single frequency GNSS stations.

Project Description

Based on a external pagegeophysical study five single frequency GPS stations have been installed on a glacier (A.P. Olsen Ice Cap) in NE Greenland where a GLOF happened annually. A reference station has been installed on the moraine.

Enlarged view: An image showing the GNSS augmented with Solar panels buried in the snow — Fig. 1: Figure 1 The GNSS stations on the glacier are set up for continuous measurements over all-year (Picture: G. Boffi, ETH Zürich)

Enlarged view: An image showing the strong wind and varying intensities of exposure to sunlight in greenland — Fig. 2: After the field campaign of Spring 2013 the first all-year around data set is available and the stations are checked and if necessary put in an operation state (Picture: D. Binder, ZAMG Vienna).

The GNSS raw data are processed kinematically with an Extended Kalman Filter. The noisy measurements are filtered through an adaptive position random walk model. The first results show that high time-resolution and filtering allow detecting anomalies in movement of the glacier. Methods shall be developed to automatize the tuning of the filter parameters and the accurate estimation of the initial coordinates.

Enlarged view: A graph showing the change in dynamics corresponding to a flood event — Fig. 3: The local height anomalies due to the GLOF are separated from the long-term ablation process by removing a trend from the height variation.

This work is part of a cooperation with GGL (ETH Zürich) and ZAMG (Vienna, Austria). ZAMG has installed and operated the network initially and uses the GNSS results for developing model of en- and subglacial processes.

Contact

Prof. Dr. Andreas Wieser

Full Professor at the Department of Civil, Environmental and Geomatic Engineering

Geosensorik und Ingenieurgeodäsie
Stefano-Franscini-Platz 5
8093 Zürich
Switzerland