EGU2020-595, updated on 04 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-595
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Observing the cryosphere with millimetre wave radar: The case study of Rhône Glacier

William D. Harcourt1, David G. Macfarlane1, Duncan A. Robertson1, Brice Rea2, and Matteo Spagnolo2
William D. Harcourt et al.
  • 1School of Physics and Astronomy, University of St Andrews, St Andrews, United Kingdom
  • 2School of Geosciences, University of Aberdeen, Aberdeen, United Kingdom

Improving our understanding of the processes governing mass loss from the cryosphere is inhibited by a lack of data at high spatial and temporal resolution. Satellite sensors can provide regional to global scale coverage of glacier processes but fail to resolve processes that occur rapidly, for example glacier calving. To observe these processes, the glaciology community must invest in new techniques that can monitor these processes adequately and fill this major research gap. Here, we will discuss the implementation of an exciting new radar system that is capable of imaging glacial terrain at a high angular resolution and during most weather conditions. The system, named AVTIS2, operates at 94 GHz (~3 mm) and offers a compromise between imaging resolution and penetration through atmospheric obscurants. AVTIS2 scans mechanically across a scene of interest in defined increments of azimuth and elevation angles and generates a 3D data cube of backscattered power. We use a point to maximum power criterion to generate point clouds and construct Digital Elevation Models (DEMs) of the terrain. Because AVTIS2 is a real aperture radar it does not require the phase stability of interferometric radars and can acquire DEMs irrespective of local environmental conditions. In this work, we have used the AVTIS2 radar to map Rhône Glacier in the Swiss Alps, representing the first ever time a millimetre wave radar has been used in this way. To improve our understanding of the performance of AVTIS2 for mapping glaciers, we have characterised the scattering properties of glacial ice at 94 GHz by calculating its Radar Cross Section (RCS). This is key to understanding the performance of AVTIS2 for mapping glaciers. This study represents the first investigation into the reflectivity of ice at millimetre wavelengths and the utility of millimetre wave radar as a surveying tool. We will report on the future application of this instrument in glaciological studies and the unique perspective it can offer.

How to cite: Harcourt, W. D., Macfarlane, D. G., Robertson, D. A., Rea, B., and Spagnolo, M.: Observing the cryosphere with millimetre wave radar: The case study of Rhône Glacier, EGU General Assembly 2020, Online, 4–8 May 2020, https://doi.org/10.5194/egusphere-egu2020-595, 2019

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Presentation version 1 – uploaded on 04 May 2020
  • CC1: Comment on EGU2020-595, Todd A. Ehlers, 05 May 2020

    Nice technique / study.  We've made similar observations on the same glacier (in ~2012) using a GPRI radar, and also with Terrestrial Lidar.  I'd be interested to see your publication when you get this finalized.  Best wishes. -T. Ehlers (Uni. Tuebingen, Germany).

    • AC1: Reply to CC1, William D. Harcourt, 07 May 2020

      Thank-you for your comments, Todd. I have seem some results of the GPRI radar at Rhone Glacier from the GAMMA team. Do you have any published results of your measurements (both GPRI and Terrestrial Lidar)? Beyond surface reflectivity, it will be very important to see how our results compare to other instruments that can generate DEMs (of course there is quite a large time separation between your measurements in 2012 and and ours in 2019).

      Best wishes,

      Will

  • CC2: Comment on EGU2020-595, Mike James, 10 May 2020

    Thanks for your contribution William - great to see AVTIS again. I was involved in the early work on Montserrat, and your comments about its 'man portability' brought back interesting memories!

    • AC2: Reply to CC2, William D. Harcourt, 12 May 2020

      Hi Mike, thank-you for your comment and I was glad to see you convening session; I am of course very much aware of your contribution to the AVTIS project! You may also be interested to know that we hope to take AVTIS2 to Svalbard next year having postponed our original fieldwork due to the COVID-19 pandemic. We think this will go beyond the proof of concept stage and generate some very useful data on glacier calving rates at high temporal resolution.