Successful end to the JOSTICE radar fieldwork

by Mette K. Gillespie, May 10, 2022

The final season of radar measurements on Jostedalsbreen Ice Cap has been concluded, with another round of ground-based measurements in the northern regions and two helicopter flights to collect ice thickness measurements in otherwise inaccessible regions.

JOSTICE are happy to report that we have achieved our overall goals for geophysical data coverage. Of course, more data can always be collected, and we have already started planning smaller fieldtrips to fill in some of the blanks in the map. In the coming years, we hope that bachelor and master students will help us extend the data coverage further in target areas.

Map showing data coverage after two field seasons of measurements. Clear reflections are observed in almost all ground-based measurements, whereas we have yet to fully check the last two rounds of helicopter measurements.

Scooter with one of the two 5 MHz IceRadar systems we used during the fieldwork on 20 – 21 April. In additions to the two low frequency systems that measured ice thickness, a Malå ProEx Ground Penetrating Radar (GPR) with 500 MHz shielded antennas was used to collect information on the snowpack. This GPR was used in regions with shallow ice (<150 m), but with a 50 MHz Rough Terrain Antenna (RTA) (photo: M. K. Gillespie).

The final measurements in the northern regions were collected by (from the left) Simon de Villiers (HVL), Kåre Øst (Norgesguidene), Even Loe (Statkraft), and Mette Gillespie (HVL). The team spent the night at Styggevasshytta, which is owned by JOSTICE partner Statkraft and is located near the Styggevatnet reservoir (photo: M. K. Gillespie).

The IceRadar is controlled remotely from a tablet. This enables us to check in real time that everything is running as it should be, and also whether the radar is picking up a signal from the bedrock below (photo: M. K. Gillespie).

Getting ready for the second round of airborne radar measurements on 7 April 2022. Jostein Bakke and Jan Magne Cederstrøm from the University of Bergen (UiB) joined Torgeir Røthe and Mette Gillespie from HVL for this part of the fieldwork (photo: M. K. Gillespie).

Airborne and measuring! Unfortunately, the weather conditions during this flight were not ideal, with some clouds and a lot of wind, in particular on the western side of the ice cap (photo: M. K. Gillespie).

Measuring on Nigardsbreen on the last day of flying on 26 April 2022. If you look closely, you will notice that one antenna arm is shorter than the other three. This arm took a beating during the first two airborne measurements and emergency tape repairs had to be made at the beginning of this last flight. Initial data check suggests that this did not affect the quality of the measurements (photo: M. K. Gillespie).

Fantastic views down the ice fall of Kjenndalsbreen. The snow is almost melted in the valley Kjenndalen (photo: M. K. Gillespie).

Airborne measurements at an ice-marginal lake near Melkevollbreen. The lake likely formed in the late 1990s and is either bedrock- or moraine-dammed. Depending on the nearby subglacial topography, the water may drain subglacially. We hope to investigate the lake and the surrounding areas in more detail, to evaluate whether the lake may cause a flooding event in the future (photo: M. K. Gillespie).