New publication: Ice-cored moraine degradation mapped and quantified using an unmanned aerial vehicle: a case study from a polythermal glacier in Svalbard

Highlights:

  • SfM photogrammetry used to produce topographic data from archive aerial imagery and UAV derived aerial imagery.
  • Datasets from 2003 and 2014 were compared to report on the de-icing of a lateral–frontal ice-cored moraine.
  • The moraine appears to be de-icing predominantly via down-wastage affording the moraine a higher degree of stability.
  • UAVs and SfM are shown to be useful tools for monitoring environmental change.

Abstract: Ice-cored lateral-frontal moraines are common at the margins of receding high-Arctic valley glaciers, but the preservation potential of these features within the landform record is unclear. Recent climatic amelioration provides an opportunity to study the morphological evolution of these landforms as they de-ice. This is important because high-Arctic glacial landsystems have been used as analogues for formerly glaciated areas in the mid-latitudes. This study uses SfM (Structure-from-Motion) photogrammetry and a combination of archive aerial and UAV (unmanned aerial vehicle) derived imagery to investigate the degradation of an ice-cored lateral-frontal moraine at Austre Lovénbreen, Svalbard. Across the study area as a whole, over an 11-year period, the average depth of surface lowering was -1.75 ± 0.89 m. The frontal sections of the moraine showed low or undetectable rates of change. Spatially variable rates of surface lowering are associated with differences in the quantity of buried-ice within the structure of the moraine. Morphological change was dominated by surface lowering, with limited field evidence of degradation via back-wastage. This is affording the moraine a greater degree of stability than observed at many other sites in Svalbard, although it is unclear whether the end point will be a fully stabilised ice-cored moraine, in equilibrium with its environment, or an ice-free lateral-frontal moraine complex. Controls on geomorphological change (e.g. topography and climate) and the preservation potential of the lateral-frontal moraine are discussed. The methods used by this research also demonstrate the potential value of SfM photogrammetry and unmanned aerial vehicles for monitoring environmental change and are likely to have wider applications in other geoscientific sub-disciplines.

Tonkin, T.N.,  Midgley, N.G., Cook, S.J. and Graham, D.G. (2015). Ice-cored moraine degradation mapped and quantified using an unmanned aerial vehicle: a case study from a polythermal glacier in Svalbard. Geomorphology, 258, pp. 1–10.

Publisher link: http://dx.doi.org/10.1016/j.geomorph.2015.12.019 (subscription required)

Preprint: https://dspace.lboro.ac.uk/2134/20069 (no subscription required; embargoed until 29 December 2016)

New publication: The potential of small unmanned aircraft systems and structure-from-motion for topographic surveys: A test of emerging integrated approaches at Cwm Idwal, North Wales

Highlights:

  • An integrated sUAS and SfM approach is used to generate topographic data.
  • The SfM dataset is compared with a total station ground survey.
  • Causes of vertical difference between the two datasets are investigated.
  • The integration of a combined sUAS and SfM approach is discussed.

Abstract: Novel topographic survey methods that integrate both structure-from-motion (SfM) photogrammetry and small unmanned aircraft systems (sUAS) are a rapidly evolving investigative technique. Due to the diverse range of survey configurations available and the infancy of these new methods, further research is required. Here, the accuracy, precision and potential applications of this approach are investigated. A total of 543 images of the Cwm Idwal moraine–mound complex were captured from a light (< 5 kg) semi-autonomous multi-rotor unmanned aircraft system using a consumer-grade 18 MP compact digital camera. The images were used to produce a DSM (digital surface model) of the moraines. The DSM is in good agreement with 7761 total station survey points providing a total vertical RMSE value of 0.517 m and vertical RMSE values as low as 0.200 m for less densely vegetated areas of the DSM. High-precision topographic data can be acquired rapidly using this technique with the resulting DSMs and orthorectified aerial imagery at sub-decimetre resolutions. Positional errors on the total station dataset, vegetation and steep terrain are identified as the causes of vertical disagreement. Whilst this aerial survey approach is advocated for use in a range of geomorphological settings, care must be taken to ensure that adequate ground control is applied to give a high degree of accuracy.

Tonkin, T.N.,  Midgley, N.G., Graham, D.G. and Labadz, J.C. (2014). The potential of small unmanned aircraft systems and structure-from-motion for topographic surveys: A test of emerging integrated approaches at Cwm Idwal, North Wales. Geomorphology, 226, pp. 35-43.

Publisher link: http://www.sciencedirect.com/science/article/pii/S0169555X14003857 (subscription required)

Preprint: https://dspace.lboro.ac.uk/2134/19115 (no subscription required)

New publication: The search for seismic signatures of movement at the glacier bed in a polythermal valley glacier

Abstract: A passive seismology experiment was conducted across the main overdeepening of Storglaciären in the Tarfala valley, northern Sweden, to investigate the spatial and temporal distribution of basal microseismic waveforms in relation to known dynamics of this small polythermal sub-arctic glacier. The high ablation rate made it difficult to keep geophones buried and well coupled to the glacier during the experiment and reduced the number of days of good-quality data collection. The characterization of typical and atypical waveforms showed that the dominant waveforms were from near-surface events such as crevassing. Waveforms resembling basal microseismic signals were very rare, and seldom observed on more than two seismic stations simultaneously. The analysis of waveforms, amplitudes and particle motions suggested a near-field origin for most events. Even though basal sliding is known to occur in the overdeepening, no convincing examples of basal waveforms were detected, suggesting basal microseismic signals are rare or difficult to detect beneath polythermal glaciers like Storglaciären. We discuss the reasons for failing to locate basal signals, consider the origin of common waveforms and make recommendations for setting up passive seismology experiments on glaciers with high ablation rates.

Project supported by a British Society for Geomorphology Research Fund Award (to JAP) and an equipment loan from the UK Natural Environment Research Council (NERC) Geophysical Equipment Facility (GEF Loan 925)

Pomeroy, J., Brisbourne, A., Evans, J. and Graham, D.J. (2013). The search for seismic signatures of movement at the glacier bed in a polythermal valley glacier. Annals of Glaciology, 54(64), pp. 149 – 156.

Publisher link: http://dx.doi.org/10.3189/2013AoG64A203 (subscription required)

Preprint: https://dspace.lboro.ac.uk/2134/13100 (no subscription required; embargoed until March 2014)

Undergraduate research bursary for Emma Jolly

David Graham has received a grant for £1440 from the Nuffield Foundation/Geological Society to fund an undergraduate research bursary to Emma Jolly.

The project will use the 3D X-ray Computed Tomography (CT) scanning facilities at the Manchester X-Ray Imaging Facility to explore the internal structure of subglacially deformed sediments. Grain orientation measurements are a standard technique in glacial sedimentology – and a relatively straightforward means of gaining significant insight into past glacial processes and environments. However, there are considerable uncertainties about the reliability of such measurements. The aim of this project is to assess the reliability of conventional field-based measurements of grain orientations by comparing them with measurements made using a CT scanner.

Emma Jolly is an undergraduate on the BSc Geography programme at Loughborough University. She is specialising in glacial geomorphology and GIS, and plans to pursue a career in environmental research or consultancy.

 

New publication: Origin, evolution and dynamic context of a Neoglacial lateral–frontal moraine at Austre Lovénbreen, Svalbard

Highlights:

  • Ground-penetrating radar used to assess Austre Lovénbreen lateral–frontal moraine
  • Buried ice forms a component of the lateral–frontal moraine
  • Ice within the lateral–frontal moraine likely to be composed of basal glacier ice
  • Post-formational deformation has thickened the basal ice sequence
  • Evidence found on 1936 oblique aerial imagery of surge front

Abstract: Moraines marking the Neoglacial limits in Svalbard are commonly ice cored. Investigating the nature of this relict ice is important because it can aid our understanding of former glacier dynamics. This paper examines the composition of the lateral–frontal moraine associated with the Neoglacial limit at Austre Lovénbreen and assesses the likely geomorphological evolution. The moraine was investigated using ground-penetrating radar (GPR), with context being provided by structural mapping of the glacier based on an oblique aerial image from 1936 and vertical aerial imagery from 2003. Multiple up-glacier dipping reflectors and syncline structures are found in the GPR surveys. The reflectors are most clearly defined in lateral positions, where the moraine is substantially composed of ice. The frontal area of the moraine is dominantly composed of debris. The core of the lateral part of the moraine is likely to consist of stacked sequences of basal ice that have been deformed by strong longitudinal compression. The long term preservation potential of the ice-dominated lateral moraine is negligible, whereas the preservation of the debris-dominated frontal moraine is high. A glacier surface bulge, identified on the 1936 aerial imagery, provides evidence that Austre Lovénbreen has previously displayed surge activity, although it is highly unlikely to do so in the near future in its current state. This research shows the value of relict buried ice that is preserved in landforms to aiding our understanding of former glacier characteristics.

Midgley, N.G., Cook, S.J., Graham, D.J. and Tonkin, T.N. (2013). Origin, evolution and dynamic context of a Neoglacial lateral–frontal moraine at Austre Lovénbreen, Svalbard. Geomorphology, 198, pp. 96–106.

Publisher link: http://dx.doi.org/10.1016/j.geomorph.2013.05.017 (subscription required)

Preprint: https://dspace.lboro.ac.uk/2134/13099 (no subscription required)

2 PhD studentships at Loughborough University, UK

The Department of Geography has secured 2 PhD studentships aligned with Loughborough University’s strategic research investment in ‘Water Resources’ and ‘Autonomous Vehicles’. Applications are now invited from exceptionally well qualified students who wish to embark on a full-time research degree programme commencing in Autumn Term 2013.

Project 1: Managing flood risks in an uncertain future

Flood risk is one of the major natural disasters globally and its management in an uncertain climatic future is becoming increasingly important. This PhD studentship welcomes proposals along the line of managing flood risk in an uncertain climatic future. The research proposal can focus on one or a combination of the following aspects: (i) modelling the physical characteristics of flood risk; (ii) evaluating its impacts; and (iii) adaptation measures. We are particularly interested in innovative research ideas that utilize novel modelling (e.g. high resolution modelling of fluvial and pluvial flooding), experimental (e.g. laboratory or field) and observational (e.g. using UASs and sensors) methods.

This PhD project will link with existing research projects on flood risks in Loughborough University. The PhD student will be jointly supervised by Dr Dapeng Yu and one or more academics from Geography or other departments in Loughborough, depending on the research direction. Please direct any questions to Dr Dapeng Yu (D.Yu2@lboro.ac.uk).

Project 2: Geo-spatial mapping using Unmanned Aircraft Systems (UAS)

This project will focus on the use of UAS for the collection of geospatial data and their use in physical geography research. We encourage potential students to approach us with project ideas in any area of physical geography, or who wish to work on technical aspects of UAS development in the context of geospatial imaging/mapping. Potential projects might lie in the area of glaciology/glacial geomorphology (e.g. the distribution dust on glacier surfaces and the effect on albedo/ablation), ecology (e.g. monitoring of forest health in the light of ash dieback), fluvial geomorphology (e.g. reach-scale sediment budgeting), or other areas in which Loughborough has expertise (see http://www.lboro.ac.uk/geography/research/).

The supervisory team will include Dr David Graham (Geography) and Dr Rene Wackrow (Civil Engineering). Other staff appropriate to the project will also be involved. Please direct enquires about this project to Dr David Graham (D.J.Graham@lboro.ac.uk).

 

Both projects will utilise the Department’s autonomous Unmanned Aircraft System (UAS). This is a GPS-controlled fixed wing surveying platform with integrated camera system, developed in association with colleagues in Aeronautical and Civil Engineering. Data processing will utilise the Department’s high-performance PC (equipped with dual Xeon E5 8-core processors, each with 64Gb memory).

They will also benefit from close collaboration with colleagues in the ‘Earth and Planetary Observation and Monitoring’ team at the British Geological Survey (including access to their rotary wing UAS).

About Loughborough University

Internationally renowned for its research excellence, Loughborough University has a vibrant research student community of around 1200 students supported by a £6 million annual investment. Comfortably ranked in the top 20 of all major UK university league tables, the University was awarded The Sunday Times University of the Year 2008-2009 and was voted The Times Higher Education ‘Best Student Experience’ in England for the past six years.

Further Information

Each studentship is valued at £13,726 per year plus tuition fees at the UK/EU rate and will run for 3 years. Applicants must be eligible to pay tuition fees at UK/EU rates.

For general information about PhD research in Geography at Loughborough and to apply, please contact Sue Clarke (S.N.Clarke@lboro.ac.uk). Please contact the individually named staff for information about the specific research projects.

General information about Department of Geography is available on our website (http://www.lboro.ac.uk/geography).

The closing date for applications is 15 March 2013.

New publication: Conversions of surface grain-size samples collected and recorded using different procedures

Abstract: Information about the grain-size distribution of the surface layer of sediment exposed on river beds is often critical in studies of fluvial hydraulics, geomorphology and ecology. A variety of sampling and analysis techniques are in common usage which produce grain-size distributions that are not directly comparable. This paper seeks to explore the appropriate conversions between different types of surface grain-size sampling methods. This is particularly timely in the light of increasingly widespread use of automatic and semi-automatic image-based measurement methods, the comparability of which with conventional measurement methods is relatively poorly constrained. For conversions between area-by-number (paint-and-pick) and grid-by-number (pebble count) samples, the empirically-derived conversion factor (±2.2) was found to be greater than that predicted by the Kellerhals and Bray model (±2), but the errors associated with using the value predicted by the model were small (3.8% in mm). For conversions between areal samples recorded by count and weight, the empirically-derived conversion factor was approximately ±2.9, but the use of the value predicted by the Kellerhals and Bray model (±3) resulted in only small errors (5.2% in mm). Similarly, for conversions between image-based grain-size distributions recorded in area-by-number and grid-by-number form, the empirically-derived conversion factor was ±1.9, but the using the model value of ±2 resulted in only small errors (4.1% in mm). Although these results are specific to the datasets analysed, the variety of sedimentary conditions included gives us confidence that the results are representative.

Graham, D.J., Rollet, A.-J., Rice, S. and Piégay, H. (2012). Conversions of surface grain-size samples collected and recorded using different procedures. Journal of Hydraulic Engineering, 138(10), 839-849.

Publisher link: http://dx.doi.org/10.1061/(ASCE)HY.1943-7900.0000595 (subscription required)

Preprint: http://hdl.handle.net/2134/9874 (no subscription required)

New publication: Applications of close-range imagery in river research

This new book chapter examines how imagery collected from the ground (as opposed to from aerial or satellite platforms) can be used as tools for research into river environments.

Bertoldi, W., Piégay, H., Buffin-Belanger, T., Graham, D.J. and Rice, S. (2012). Applications of Close-Range Imagery in River Research. In Carbonneau, P. and Piégay, H. (eds), Fluvial Remote Sensing for Science and Management.  341-366. Wiley-Blackwell, Chichester.

Publisher link: http://dx.doi.org/10.1002/9781119940791.ch15 (subscription required)

New publication: Origin and significance of ‘dispersed facies’ basal ice: Svinafellsjokull, Iceland

Abstract: Dispersed facies basal ice – massive (i.e. structureless) ice with dispersed debris aggregates – is present at the margins of many glaciers and, as a product of internal glacial processes, has the potential to provide important information about the mechanisms of glacier flow and the nature of the subglacial environment. The origin of dispersed facies is poorly understood, with several hypotheses having been advanced for its formation, and there is disagreement as to whether it is largely a sedimentary or a tectonic feature. We test these established hypotheses at the temperate glacier Svínafellsjökull, Iceland, and find that none fully account for dispersed facies characteristics at this location. Instead, dispersed facies physical, sedimentological and stable-isotope (δ18O, δD) characteristics favour a predominantly tectonic origin that we suggest comprises the regelation and strain-induced metamorphism of debris-rich basal ice that has been entrained into an englacial position by tectonic processes operating at the base of an icefall. Further thickening of the resultant dispersed facies may also occur tectonically as a result of ice flow against the reverse bed slope of a terminal overdeepening. Lack of efficient subglacial drainage in the region of the overdeepening may limit basal melting and thus favour basal ice preservation, including the preservation of dispersed facies. Despite the relatively low sediment content of dispersed facies (∼1.6% by volume), its thickness (up to 25 m) and ubiquity at Svínafellsjökull results in a significant contribution to annual sediment discharge (1635-3270 m3 a−1) that is ∼6.5 times that contributed by debris-rich stratified facies basal ice.

Cook, S.J., Swift, D.A., Graham, D.J. and Midgley, N.G. (2011). Origin and significance of ‘dispersed facies’ basal ice: Svinafellsjokull, Iceland. Journal of Glaciology, 57 (204), pp. 710-720.

Publisher link: http://dx.doi.org/10.3189/002214311797409703 (subscription required)