Ice thickness of Kilimanjaro's Northern Ice Field mapped by ground-penetrating radar ...

• Main Authors: Bohleber, Pascal, Sold, Leo, Hardy, Douglas R, Schwikowski, Margit, Klenk, Patrick, Fischer, Andrea, Sirguey, Pascal, Cullen, Nicolas J, Potocki, Mariusz, Hoffmann, Helene, Mayewski, Paul
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2016
• Subjects: ice core
• Online Access: https://dx.doi.org/10.1594/pangaea.867908; https://doi.pangaea.de/10.1594/PANGAEA.867908

Although its Holocene glacier history is still subject to debate, the ongoing iconic decline of Kilimanjaro's largest remaining ice body, the Northern Ice Field (NIF), has been documented extensively based on surface and photogrammetric measurements. The study presented here adds, for the first time, ground-penetrating radar (GPR) data at center frequencies of 100 and 200 MHz to investigate bedrock topography, ice thickness and internal stratigraphy at NIF. The direct comparison of the GPR signal to the visible glacier stratigraphy at NIF's vertical walls is used to validate ice thickness and reveals that the major internal reflections seen by GPR can be associated with dust layers. Englacial reflections can be traced consistently within our 200 MHz profiles, indicating an undisturbed internal stratigraphy within NIF's central flat area. We show that it is possible to follow isochrone layers between two former NIF ice core drilling sites and a sampling site on NIF's vertical wall. As a result, these ... : In summer 2015, a ground-penetrating radar (GPR) survey was carried out at Kilimanjaro's largest remaining ice body, the Northern Ice Field (NIF). Two GPR systems at center frequencies of 100 and 200 MHz were used to investigate bedrock topography, ice thickness and internal stratigraphy at NIF. A photometric estimation of the height of NIF's vertical wall was used to validate ice thickness inferred from GPR using a constant wave speed of 0.168 m/ns. The GPR profiles revealed an ice thickness ranging between (6.1 ± 0.5) and (53.5 ± 1.0) m. These data were combined with a very high resolution digital elevation model in order to spatially extrapolate ice thickness and give an estimate of the total ice volume remaining at NIF's southern portion. ...