Validation of airborne and satellite altimetry data by Arctic Truck citizen science




Satellite Validation, Altimetry, CryoSat-2, Operation IceBridge, Citizen science


The elevation of ice sheets response dynamically to climate change and satellite altimetry is the preferred tool for evaluating the ice sheet-wide changes. In-situ validation are needed to ensure the quality of the observed elevation changes, but the coast is most often the limiting factor for the amount of in-situ data available. As more and more tourists are accessing the ice sheets, citizen science might provide the needed in-situ data in an environmental and cost-efficient way. Here, we investigate opportunistic kinematic-GPS profiles across the Greenland ice sheet, collected the American-Icelandic Expedition on the Greenlandic icecap 2018. First, the collected GPS-data are tested against widely used NASA Operation IceBridge airborne lidar-scannings, and shows good agreement, with an accuracy of 11 cm. The main difference is attributed to changes in the compaction of the snow as encountered while driving, as well as changing tire pressures. The kinematic-GPS data is then used for satellite validation by inter-comparing it with data from ESA's CryoSat-2 mission. Here, a bias in the two records of 89 cm is observed, with the Cryosat-2 observation originating from the subsurface of the ice sheet. This points to surface penetration of Ku-band radar on the Greenland ice sheet, and the observed magnitude is in accordance with the literature. Finally, we assess the long-term durability of citizen science kinematic-GPS data, when compared to a profile obtained in 2005 near Kangerlussuaq, West Greenland. Here, the records show an average ice elevation decreased of 9 meters and with peaks at 25.7 meters. This result show how kinematic-GPS data can be used to see the full impact of climate change by repeat measurements. Thereby are citizen science kinematic-GPS data shown to be a highly versatile approach to acquire high-resolution validation data for satellite altimetry, with the added benefit of potentially direct sampling properties of the surface and firn, when applying traditional airborne platforms. Thereby linking up with citizen-science expeditions is truly a beneficial way of providing cost-efficient satellite validations and may also have a societal impact by involving more in the climate monitoring of ice sheets.


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ACS Team & MSSL Team. 2015: CryoSat ground segment, instrument processing facility – L2 products format specification (L2-FMT). Baseline C version. Advanced Computer Systems, Doc. No.: CS-RS-ACS-GS-5123, 98 pp.

Ahlstrøm, A.P. et al. 2008: A new programme for monitoring the mass loss of the Greenland ice sheet. Geological Survey of Denmark and Greenland Bulletin 15, 61–64.

Bouzinac, C. 2012: CryoSat Product Handbook. Report no., ESRIN ESA and Mullard Space Science Laboratory – University College London, ESA Esrin, Frascati, Italy.

Fausto, R.S., van As, D. & PROMICE project team. 2012: Ablation observations for 2008–2011 from the programme for monitoring of the Greenland ice sheet, PROMICE. Geological Survey of Denmark and Greenland Bulletin 26, 73–76.

Forsberg, R., Sørensen, L. & Simonsen, S. 2017: Greenland and Antarctica ice sheet mass changes and effects on global sea level. In: Cazenave, A. et al. (eds): Integrative study of the mean sea level and its components. Space Sciences Series of ISSI 58, 91–106.

Howat, I.M., Negrete, A. & Smith, B.E. 2014: The Greenland Ice Mapping Project (GIMP) land classification and surface elevation datasets. The Cryosphere Discussions 8(1), 453–478.

Khan, S.A., Aschwanden, A., Bjørk, A.A., Wahr, J., Kjeldsen, K.K. & Kjær, K.H. 2015: Greenland ice sheet mass balance: a review. Reports on Progress in Physics 78(4), 046801.

Krabill, W., et al. 2000: Greenland ice sheet: high-elevation balance and peripheral thinning. Science 289(5478), 428–430.

Martin, C.F., Krabill, W.B., Manizade, S.S., Russell, R.L., Sonntag, J.G., Swift, R.N. & Yungel, J.K. 2012: Airborne topographic mapper calibration procedures and accuracy assessment. Nasa Technical Memorandum, TM–2012-215891 (February). Goddard Space Flight Center Greenbelt, Maryland, USA.

Nilsson, J. et al. 2015: Greenland 2012 melt event effects on Cryosat-2 radar altimetry. Geophysical Research Letters 42(10), 3919–3926.

Remy, F., Flament, T., Michel, A. & Blumstein, D. 2015: Envisat and SARAL/AltiKa observations of the Antarctic ice sheet: a comparison between the Ku-band and Ka-band. Marine Geodesy 38(suppl. 1), 510–521.

Seitz, B., Mavrocordatos, C., Rebhan, H., Nieke, J., Klein, U., Borde, F. & Berruti, B. 2010: The sentinel-3 mission overview. International Geoscience and Remote Sensing Symposium (IGARSS), Honolulu, Hawaii, 25–30 July 2010, 5650772, 4208–4211.

Shepherd, A., et al. 2018: Mass balance of the Antarctic ice sheet from 1992 to 2017. Nature 558, 219–222.

Simonsen, S.B. & Sørensen, L.S.L. 2017: Implications of changing scattering properties on Greenland ice sheet volume change from Cryosat-2 altimetry. Remote Sensing of Environment 190, 207–216.

Skourup, H., Barletta, V.R., Einarsson, I., Forsberg, R., Haas, C., Helm, V., Hendricks, S., Hvidegaard, S.M. & Sørensen, L.S. 2013: ESA CryoVEx 2011: airborne field campaign with ASIRAS radar, EM introduction sounder and laser scanner. DTU Space, Lyngby, Denmark, Technical Report 1, 120 pp.

Skourup, H., Einarsson, I., Forsberg, R., Haas, C., Helms, V., Hvidegaard, S.M., Nilsson, J., Olesen, A.V. & Olesen, A.K. 2012: ESA CryoVEx 2012: Airborne field campaign with ASIRAS radar, EM introduction sounder and laser scanner. DTU Space, Lyngby, Denmark, Technical Report 2, 105 pp.

Slater, T., Shepherd, A., McMillan, M., Armitage, T.W., Otosaka, I. & Arthern, R.J. 2019: Compensating changes in the penetration depth of pulse-limited radar altimetry over the Greenland ice sheet. IEEE Transactions on Geoscience and Remote Sensing 57(12), 9633–9642.

Sørensen, L.S., Simonsen, S.B., Forsberg, R., Khvorostovsky, K., Meister, R. & Engdahl, M.E. 2018a: 25 years of elevation changes of the Greenland Ice Sheet from ERS, Envisat, and CryoSat-2 radar altimetry. Earth and Planetary Science Letters 495, 234–241.

Sørensen, L.S., et al. 2018b: Validation of CryoSat-2 SARIn data over Austfonna ice cap using airborne laser scanner measurements. Remote Sensing 10(9), 1354, 12 pp.

Studinger, M. 2018: IceBridge ATM L2 Icessn elevation, slope, and roughness, Version 2. 2018 data, data set ID: ILATM2.

Studinger, M., Koenig, L., Martin, S. & Sonntag, J. 2010: Operation icebridge: using instrumented aircraft to bridge the observational gap between icesat and icesat-2. International Geoscience and Remote Sensing Symposium (IGARSS), Honolulu, Hawaii, 25–30 July 2010, 5650555, 1918–1919.

Ulaby, F.T. & Stiles, W.H. 1981: Dielectric properties of snow. pp. 91–103. Lawrence, KS: Remote Sensing Laboratory, University of Kansas Center Research Inc.



How to Cite

Stokholm, . A. ., Hvidegaard, S. M., Forsberg, R., & Simonsen, S. B. (2021). Validation of airborne and satellite altimetry data by Arctic Truck citizen science. GEUS Bulletin, 47.




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