JWG C.3: Geodesy for the Cryosphere: advancing the use of geodetic data in polar climate modelling

Chair: Bert Wouters (Netherlands)
Vice-Chair: Ingo Sasgen (Germany)
(Affiliation: Commission 2, Commission 3, GGOS)


Over the last two decades, tremendous progress has been made in the development and use of geodetic methods to observe the rapidly emerging changes in the cryosphere. Variations in mass, elevation, grounded ice extent and flow speed are now being monitored on a routine basis using geodetic techniques such as gravimetry, (In)SAR, altimetry, GNSS and the like. Additionally, observations of land motion provide indirect information on the past evolution of ice masses. These geodetic observations have led to a leap forward in our understanding of the cryosphere as part of the climate system, and unambiguously have shown that the Earth’s ice sheets and glaciers are increasingly losing mass and now represent the largest land-based contribution to global mean sea level rise.

Yet, compared to other fields of climate science (e.g. hydrology, oceanography and atmospheric sciences), inclusion of geodetic data is lagging behind in cryosphere modelling and remains mostly limited to validation of model output at large spatial scales. Data assimilation and the combination of multiple observables are still at an early development stage andr arely used to exploit the full potential of the geodetic measurements. To date, it remains a challenge incorporate the geodetically observed transitions in the cryosphere into future simulations. Within this JWG, we aim to bridge the currently existing gap between the geodetic and modelling communities, as detailed in our objectives below.


Within this JWG, we aim to:

  • identify current bottlenecks in using geodetic data for validation and assimilation efforts in ice sheet and glacier modelling
  • communicate the possibilities and limitations of geodetic data to the modelling community
  • document the wishes of the modelling community for geodetic data (resolution, projection, uncertainty definitions, etc.)
  • identify geodetic data relevant for the evaluation of projection ensembles
  • based on the above, list a set of recommendations for the geodetic community to advance the use geodetic data in modelling efforts.
  • Explore potential of future geodetic observables for their use in glaciology

Program of Activities

  • Summarize and gather state-of-the-art papers on geodetic observation techniques and data on the IAG website for non-geodetic audiences
  • In close collaboration with the representatives of the cryosphere modelling community or through a open survey, identify requirements and derive concepts of geodetic data assimilation into ice sheet and glacier modelling
  • List a set of recommended processing steps and standards for the geodetic community on the IAG website or in a white paper
  • Schedule a yearly strategic splinter meeting to review progress and define strategic tasks for the upcoming year
  • Acknowledge and promote work of talented young scientist contributing into the aims of JWG, through a yearly award or promotion on the ICCC website
  • Communicate activities through IAG’s social media accounts


  • Mike Bevis (USA)
  • Matthias Braun (Germany)
  • William Colgan (Denmark)
  • Christoph Dahle (Germany)
  • Olga Engels (Germany)
  • Xavier Fettweis (Belgium)
  • Dana Floricioiu (Germany)
  • Heiko Goelzer (Netherlands)
  • Natalya Gomez (USA)
  • Martin Horwath (Germany)
  • Michalea King (USA)
  • Kristine Larson (USA)
  • Jan Lenaerts (USA)
  • Lin Liu (Hong Kong)
  • Malcolm McMillan (UK)
  • Brice Noël (Netherlands)
  • Masashi Niwano (Japan)
  • Louise Sandberg Sørensen (Denmark)
  • Mirko Scheinert (Germany)
  • Nicole Schlegel (USA)
  • David Wiese (USA)

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