Bias-corrected estimates of glacier thickness in the Columbia River Basin, Canada

Pelto, Ben M.; Maussion, Fabien; Menounos, Brian; Radić, Valentina; Zeuner, Maurice

doi:10.1017/jog.2020.75

Cited by 19 publications

(36 citation statements)

References 66 publications

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“…Models of glacier thickness are increasingly incorporating mass conservation and global satellite remote-sensing datasets, but there remains an outstanding need for additional thickness measurements to both validate and refine those models' underlying assumptions (e.g., Farinotti et al, 2019;Pelto et al, 2020). Our synthesis suggests a higher upper limit (~30 MHz) on potentially suitable radar sounders for sounding temperate ice up to ~700 m thick.…”

Section: Discussionmentioning

confidence: 90%

Brief communication: An empirical relation between center frequency and measured thickness for radar sounding of temperate glaciers

MacGregor¹,

Studinger²,

Arnold³

et al. 2021

Preprint

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Abstract. Radar sounding of the thickness of temperate glaciers is more challenging than for polar ice sheets, due to the former's greater volume scattering (englacial water), surface scattering (crevasses and debris) and dielectric attenuation rate (warmer ice). Lower frequency (~1–100 MHz) radar sounders are commonly deployed to mitigate these effects, but the lack of a synthesis of existing radar-sounding surveys of temperate glaciers limits progress in system and survey design. Here we use a recent global synthesis of measured glacier thickness to evaluate the relation between the radar center frequency and maximum thickness. From a maximum reported thickness of ~1500 m near 1 MHz, the maximum thickness sounded decreases with increasing frequency by ~500 m per frequency decade. Newer airborne radar sounders generally outperform older, ground-based ones at comparable frequencies, so radar-sounder success is also influenced by system design and processing methods. Based on globally modeled glacier thicknesses, we conclude that a multi-element airborne radar sounder with a center frequency of ≤ 30 MHz could survey most temperate glaciers more efficiently than presently available systems.

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Section: Discussionmentioning

confidence: 90%

Brief communication: An empirical relation between center frequency and measured thickness for radar sounding of temperate glaciers

MacGregor¹,

Studinger²,

Arnold³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Ice thickness measurements from ice penetrating radar (IPR) are available from B. M. Pelto, Maussion, Menounos, Radić, and Zeuner (2020) for the three glaciers, with uncertainty estimated between 5-10% depending on the quality of the bed reflection. We also use modeled ice thickness from Farinotti et al (2019) and B. M. Pelto et al (2020).…”

Section: Ice Thicknessmentioning

confidence: 99%

“…For ice thickness in western North America, Farinotti et al (2019), hereafter referred to as FAR19, use three models (Frey et al, 2014;Huss & Farinotti, 2012;Maussion et al, 2019). B. M. Pelto et al (2020) optimized distributed ice thickness for all three study glaciers using a cross-validation approach to minimize error between observed and modeled ice thickness with the Open Global Glacier Model (OGGM) (Maussion et al, 2019).…”

Section: Ice Thicknessmentioning

confidence: 99%

“…We assume an uncertainty of 10% for IPR observations (B. M. Pelto et al (2020)). For the modeled ice ice thickness estimates, we double the average relative error from B. M. Pelto et al (2020) for these three glaciers (5.1%) as we are using the ice thickness at-a-point rather than glacier-wide, yielding an uncertainty on ice thickness (σH ) of 10.2%. IPR estimates have gaps in coverage along many flux gates (Fig.…”

Section: Uncertainties On the Ice Fluxesmentioning

confidence: 99%

“…Glaciology. Please see Appendix A: Authorship Statements for details of the contributions of each author Pelto, B. M., Maussion, F., Menounos, B., Radić, V., and Zeuner, M. (2020)…”

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confidence: 99%

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An approach to remotely monitor glacier mass balance at seasonal to annual time scales, Columbia and Rocky Mountains, Canada.

Pelto¹

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My dissertation investigates glacier mass change in the Columbia and Rocky Mountains of British Columbia. In chapter one I discuss the importance of the cryosphere and glaciers, introduce the climate and glaciers of the study region, and outline the objectives and structure of this dissertation. Previous work established the feasibility of geodetic methods to accurately produce winter glacier mass balance and annual glacier mass balance. These studies demonstrate that geodetic surveys can be used to estimate mass balance during the accumulation season or for one glacier over a number of years. In chapter two, I refine these published methods to measure seasonal and annual mass balance for six glaciers within two mountain ranges from 2014–2018. I use synchronous field-based glaciological measurements, airbornelaser scanningsurveys (ALS) and satelliteimagery to quantify seasonal glacier mass change from 2014–2018. Chapter three reports on radar surveys I completed of the study glaciers, adding important observations to the global database of ice thickness. I use these observations and an existing flowline model, driven with observations of surface mass balance and glacier elevation to bias-correct ice thickness estimates for each glacier. Finally, I use the model to estimate ice thickness for all glaciers in the Columbia Basin and estimate total ice volume. Chapter four builds upon previous work which used surface topography, glacier mass balance, ice thickness, and ice velocity data to estimate ice flux at discrete glacier cross-sections. Previous efforts to infer the spatial distribution of mass balance have focused on glacier tongues. I expand upon this method, calculating surface mass balance between flux gates over the entire elevation range of three glaciers, over three years. I derive the altitude-mass balance relation and demonstrate that the relation can be accurately described with high-resolution elevation and ice flux data, and suggest that this method can be expanded for large-scale estimates. Chapter five summarizes the study’s major findings, highlights its limitations and discussed its broader implications. Finally, I make recommendations that will address knowledge gaps, and improve our understanding of changing glacier conditions and ability to model glacier dynamics.

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Testing the performance of ice thickness models to estimate the formation of potential future glacial lakes in Austria

Otto

Prasicek

Binder

et al. 2021

Earth Surf Processes Landf

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The emergence of glacial lakes is a significant consequence of global climate change in high mountain regions. Recent developments in ice thickness modelling combined with high-resolution glacier surface data led to the generation of modelling approaches to simulate the ice-free bedrock topography below current glaciers and to detect potential glacier bed overdeepenings (GBO) that may form into future lakes. We simulated the subglacial topography in the Austrian Alps using two different ice thickness models. Glaciers in the study area differ significantly from glaciers investigated in previous studies on potential future lakes because of their in general small size and location often restricted to cirques. The aim of this study is to estimate the number and location of potential future lakes in Austria. We tested the performance of ice thickness models for modelling of potential future lakes in an environment dominated by mountain glaciers that are under high stress of climate change.Modelling results are compared with lakes that evolved since the modelling periods and with data on subglacial topography derived from geophysical surveys. Results show significant differences in model performance concerning the total ice volume and the number of simulated GBOs. The number and total area of the modelled GBOs is overestimated, compared with the number of lakes that have evolved in the past. Most GBOs are simulated for valley type glaciers, even though most glaciers are mountain types. This does not match with the location of existing glacial lakes that are dominantly found in cirques. We ascertain that this modelling approach performs better on large valley type glaciers and less well on mountain glaciers. Intersecting the modelling runs indicates that up to 42 new lakes may form within 23 glaciers in Austria covering a total area of 2 km 2 .

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Bias-corrected estimates of glacier thickness in the Columbia River Basin, Canada

Cited by 19 publications

References 66 publications

Brief communication: An empirical relation between center frequency and measured thickness for radar sounding of temperate glaciers

Brief communication: An empirical relation between center frequency and measured thickness for radar sounding of temperate glaciers

An approach to remotely monitor glacier mass balance at seasonal to annual time scales, Columbia and Rocky Mountains, Canada.

Testing the performance of ice thickness models to estimate the formation of potential future glacial lakes in Austria

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