Upward-looking Impulse Radar for continuous monitoring of Snow Accumulation and Melt in Greenland (URSAM)
Final Report Abstract
Within the reported project duration, I was able to demonstrate the capability of upGPR technology to produce long-term monitoring of liquid water behavior and changes in snow and firn in Greenland. Such data can and are used to evaluate and validate modeling approaches and remote sensing data. There is a distinct need for the ability of continuous liquid water monitoring in firn to improves our knowledge on water transport in layered cold media. For instance, the implementation of upGPR-determined water retention per day improve even very simple model approaches. For a widely used and accepted regional climate model (MAR), we could show that individual parameters such as liquid water content and percolation as well as bulk density are not adequately simulated. In continuously changing environmental conditions, it might be inadequate to tune models without simulating the physics correctly. This may lead to wrong estimates of changes in mass balances. In a publication lead by Dr. MacFerrin, we could demonstrate the global impacts of recent changes within the percolation zone of the GrIS and how much such areas will contribute to future sea level rise for different climate scenarios. The current upGPR location as well may contribute to sea level changes in the near future, if record melt events frequently arise in Greenland. Together with the numerous publications, this demonstrates the high impact of the conducted research and the ongoing interest in data record at the site. So far, the upGPR stopped working during each winter season or earlier. Constant improvements in hard- and software were performed and this winter season, I received reports of good health of the system. I am of good hope that conducted improvements helped to perform measurements all winter long and the system continues to run until the next data download, which is expected to happen in April/ May 2020. In addition, I already published a case study leading280330996_E_1 to future proposals combining point observations and area-wide data from remote sensing sources on melt and accumulation. It would be ideal to combine a transect of point observations using low-cost/ low-maintenance GNSS receivers with one upGPR system and remote sensing data from radar platforms such as Sentinel-1. The high repeat passes of Sentinel-1 and the point measurements would lead to deep insights into spatial distribution of melt and accumulation in Greenland. In a recent publication, Henkel et al. (2018) could show that GNSS data can provide information on accumulation as well. However, there is no application in harsh polar environments so far proving its reliability.
Publications
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(2018): Seasonal monitoring of melt and accumulation within the deep percolation zone of the Greenland Ice Sheet and comparison with simulations of regional climate modeling, The Cryosphere, 12, 1851-1866
Heilig, A., Eisen, O., MacFerrin, M. Tedesco, M. and Fettweis, X.
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(2019): Discriminating wet snow and firn for Alpine glaciers using Sentinel-1 data: A case study at Rofental, Austria, Geosciences, 9(2), 69
Heilig, A., Wendleder, A., Schmitt, A. and Mayer, C.
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(2019): Firn data compilation reveals widespread decrease of firn air content in western Greenland, The Cryosphere, 13, 845–859
B. Vandecrux, M. MacFerrin, H. Machguth, W. Colgan, D. van As, A. Heilig, C. Stevens, C. Charalampidis, R. Fausto, E. Morris, E. Mosley-Thompson, L. Koenig, L. Montgomery, C. Miège, S. Simonsen, T. Ingeman- Nielsen and J. Box
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(2019): Rapid expansion of Greenland’s low-permeability ice slabs, Nature, 573, 403–407
MacFerrin, M, Machguth, H., van As, D., Charalampidis, C., Stevens, C. M., Heilig, A., Vandecrux, B., Langen, P. L., Mottram, R., Fettweis, X., Van den Broeke, M. R., Pfeffer, W.T., Moussavi, M. and Abdalati, W.
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(2020). Relating regional and point measurements of accumulation in southwest Greenland., The Cryosphere, 14, 385-402
Heilig, A., Eisen, O., Schneebeli, M., MacFerrin, M. Stevens, C. M., Vandecrux, B. and Steffen, K.
