Monitoring Argualas rock glacier dynamics combining InSAR, GNSS and UAV data

The Pyrenees range is the most southern European region with active glaciers and rock glaciers. In the current climate change context, their depth, extent and viability are rapidly declining. Even though they are usually located in high-elevation and remote areas, their dynamics can affect human settlements and activities. Mapping and monitoring these ice bodies will provide more information about their past, present and future evolution.

Remote sensing data provides extensive information, especially in rough mountainous areas and inaccessible or distant regions. Differential and Multitemporal interferometry (DInSAR and MT-InSAR) has been extensively proven to be a valuable tool to detect ground deformations, but also works to provide insightful results over glacial and periglacial environments. Since many authors have found SAR data useful in this context, there is a scarcity of works that exploit the high spatial and temporal resolution of X-band dense constellations such as COSMO-SkyMed. On the other hand, this kind of ice bodies are usually located over low satellite-visibility areas (related to shadow and layover effects), increasing the importance of alternative information, such as that provided by in-situ (GNSS) or near-remote sensing (UAV).

This work compares coverture and displacement results from Sentinel-1 C-band (both DInSAR and MT-InSAR) and COSMO-SkyMed X-band data. MT-InSAR results from EGMS revealed low coverage due to geometrical and snow-cover issues, while DInSAR results from both constellations provide better coverage results. UAV flights over the glacier allowed perfect coverage and high spatial resolution, but lacked in temporal resolution. Lastly, a GNSS measurement grid was redeployed over the glacier and will provide displacement data for future campaigns and for comparison with previous campaigns in the 90s. Combining data from UAV flights, three-dimensional displacement is estimated and compared with InSAR results, after projection in the Line of Sight (LOS), with the InSAR displacements. This work is part of JDC2023-052719-I, financed by MCIU/AEI/10.13039/501100011033 y and FSE+.