UAV and GPR Data Integration in Glacier Geometry Reconstruction: A Case Study from Irenebreen, Svalbard

Jānis Karušs,Ireneusz Sobota,Jurijs Ješkins,Kristaps Lamsters,Pēteris Džeriņš

doi:10.3390/rs14030456

Jānis Karušs, Ireneusz Sobota + Show 3 more

Open Access

https://doi.org/10.3390/rs14030456

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Abstract

Although measurements of thickness and internal structure of glaciers are substantial for the understanding of their evolution and response to climate change, detailed data about polythermal glaciers, are scarce. Here, we present the first ground-penetrating radar (GPR) measurement data of Irenebreen, and high-resolution DEM and orthomosaic, obtained from unmanned aerial vehicle (UAV) photogrammetry. A combination of GPR and UAV data allowed for the reconstruction of the glacier geometry including thermal structure. We compare different methods of GPR signal propagation speed determination and argue that a common midpoint method (CMP) should be used if possible. Our observations reveal that Irenebreen is a polythermal glacier with a basal temperate ice layer, the volume of which volume reaches only 12% of the total glacier volume. We also observe the intense GPR signal scattering in two small zones in the ablation area and suggest that intense water percolation occurs in these places creating local areas of temperate ice. This finding emphasizes the possible formation of localised temperate ice zones in polythermal glaciers due to the coincidence of several factors. Our study demonstrates that a combination of UAV photogrammetry and GPR can be successfully applied and should be used for the high-resolution reconstruction of 3D geometries of small glaciers.

Highlights

The aim of this study is to demonstrate that unmanned aerial vehicle (UAV) and ground-penetrating radar (GPR) data integration are the most optimal method today for the characterisation of small glacier geometry including the ice surface and bed topography, ice thickness and thermal structure
Our observations reveal that Irenebreen, similar to its neighbouring Waldemarbreen [14] is a polythermal glacier with cold ice and a basal temperate ice layer, the volume of which reaches 10% to 12% of all glacier volume depending on the used GPR signal propagation speed in the temperate ice
Our study demonstrates that an integrated approach of UAV and GPR survey is probably the most effective solution today for the high-resolution reconstruction of small glacier geometry

Summary

Introduction

For the understanding of thermal regime, dynamics and following response to climate change, detailed data about the internal structure, volume, and distribution of temperate ice in polythermal glaciers are necessary [1]. It is especially crucial to determine glacier volume as precisely as possible, especially when small glaciers are considered [2,3]. Despite the long history of glacier studies in Svalbard, measurements of ice thickness of individual glaciers with geophysical methods or drillings are still scarce [4,5,6,7], etc., due to the remote location of the archipelago. The same can be stated about the determination of the distribution of cold and temperate ice [5,6,7], etc

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