Revealing recent calving activity of a tidewater glacier with terrestrial LiDAR reflection intensity

Podgórski, Julian; Pętlicki, Michał; Kinnard, Christophe

doi:10.1016/j.coldregions.2018.03.003

Cited by 15 publications

(10 citation statements)

References 66 publications

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“…However, most of these studies rely on indirect methods (measuring a quantity that is then used to infer the volume) (O'Neel et al, 2010;Walter et al, 2010;Bartholomaus et al, 2012;Glowacki et al, 2015) or discontinuous (Warren et al, 1995;O'Neel et al, 2003) measurements and thus lack continuous direct observations of calving event sizes. Promising direct methods (measuring directly the volume) for determining calving event sizes are repeated surveys by photogrammetry using Unmanned aerial vehicle (UAV) data (Ryan et al, 2015;Jouvet et al, 2017Jouvet et al, , 2019 and by terrestrial laser scanning (Petlicki and Kinnard, 2016;Podgórski et al, 2018). For high calving activity these methods tend to miss individual events due to limited temporal resolution and their dependency on suitable weather conditions.…”

Section: Introductionmentioning

confidence: 99%

Drivers of Recurring Seasonal Cycle of Glacier Calving Styles and Patterns

et al. 2021

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Calving is a crucial process for the mass loss of outlet glaciers draining the Greenland ice sheet. Moreover, due to a lack of observations, calving contributes to large uncertainties in current glacier flow models and projections. Here we investigate the frequency, volume and style of calving events by using high-resolution terrestrial radar interferometer (TRI) data from six field campaigns, continuous daily and hourly time-lapse images over 6 years and 10-s time-lapse images recorded during two field campaigns. The results demonstrate that the calving front of Eqip Sermia, a fast flowing, highly crevassed outlet glacier in West Greenland, follows a clear seasonal cycle showing a distinct pattern in areas with subglacial discharge plumes, shallow bed topography and during the presence and retreat of proglacial ice mélange. Calving event volume, frequency and style vary strongly over time depending on the state in the seasonal cycle. Strong spatial differences between three distinctive front sectors with differing bed topography, water depth and calving front slope were observed. A distinct increase in calving activity occurs in the early melt season simultaneously when ice mélange disappears and meltwater plumes become visible at the fjord surface adjacent to the ice front. While reduced retreat of the front is observed in shallow areas, accelerated retreat occurred at locations with subglacial meltwater plumes. With the emergence of these plumes at the beginning of the melt season, larger full thickness calving events occur likely due to undercutting of the calving front. Later in the melt season the calving activity at subglacial meltwater plumes is similar to the neighboring areas, suggesting the presence of plumes to become less important for calving. The results highlight the significance of subglacial discharge and bed topography on the front geometry, the temporal variability of the calving process and the variability of calving styles.

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Section: Introductionmentioning

confidence: 99%

Drivers of Recurring Seasonal Cycle of Glacier Calving Styles and Patterns

et al. 2021

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“…Time‐lapse cameras, whilst having sufficient temporal resolution, produce two‐dimensional imagery that is not easily converted into three‐dimensional (3D) volumes of calving events (How et al., 2018; Mallalieu et al., 2017; Vallot et al., 2019). Terrestrial laser scanning has been used (Pętlicki & Kinnard, 2016; Podgórski et al., 2018), but repeat surveys with this technique are problematic due to the large quantity of data in each survey, as well as the significant logistical effort required and the relatively short range of the instrument. Continuous and detailed data sets on calving behavior at tidewater glaciers are thus lacking, yet understanding this process is crucial for advancing numerical models and for better prediction of tidewater‐glacier behavior and consequent sea‐level rise.…”

Section: Introductionmentioning

confidence: 99%

Calving of a Large Greenlandic Tidewater Glacier has Complex Links to Meltwater Plumes and Mélange

et al. 2021

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• We derive a record of 8,026 calving events and sizes at Store Glacier in July 2017 using a terrestrial radar interferometer • We find no single clear control on calving and clear variations in calving behaviour over time, producing a bimodal calving event-size distribution • Our findings suggest that grouping glaciers by their dominant calving mechanism is not tenable, as this mechanism can change over time Accepted Article This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

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“…Furthermore, they are independent of visibility conditions in contrast to optical methods. However, inferring ice volumes from those signals using physical models is challenging (Podolskiy and Walter, 2016;Aster and Winberry, 2017). For example, it requires different approaches dependent on the calving style, i.e., for glacial earthquake signals from buoyancydriven nontabular iceberg calving such as observed in Greenland (e.g., Murray et al, 2015;Sergeant et al, 2019) or for seismic calving signals generated during iceberg-sea or lake surface interactions (Bartholomaus et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Contribution of calving to frontal ablation quantified from seismic and hydroacoustic observations calibrated with lidar volume measurements

Köhler

Pętlicki²,

Lefeuvre

et al. 2019

The Cryosphere

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Abstract. Frontal ablation contributes significantly to the mass balance of tidewater glaciers in Svalbard and can be recovered with high temporal resolution using continuous seismic records. Determination of the relative contribution of dynamic ice loss through calving to frontal ablation requires precise estimates of calving volumes at the same temporal resolution. We combine seismic and hydroacoustic observations close to the calving front of Kronebreen, a marine-terminating glacier in Svalbard, with repeat lidar scanning of the glacier front. Simultaneous time-lapse photography is used to assign volumes measured from lidar scans to seismically detected calving events. Empirical models derived from signal properties such as integrated amplitude are able to replicate volumes of individual calving events and cumulative subaerial ice loss over different lidar scan intervals from seismic and hydroacoustic data alone. This enables quantification of the contribution of calving to frontal ablation, which we estimate for Kronebreen to be about 18 %–30 %, slightly below the subaerially exposed area of the glacier front. We further develop a model calibrated for the permanent seismic Kings Bay station (KBS) at about 15 km distance from the glacier front, where 15 %–60 % of calving events can be detected under variable noise conditions due to reduced signal amplitudes at distance. Between 2007 and 2017, we find a 5 %–30 % contribution of calving ice blocks to frontal ablation, which emphasizes the importance of underwater melting (roughly 4–9 m d−1). This study shows the feasibility to seismically monitor not only frontal ablation rates but also the dynamic ice loss contribution continuously and at high temporal resolution.

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Revealing recent calving activity of a tidewater glacier with terrestrial LiDAR reflection intensity

Cited by 15 publications

References 66 publications

Drivers of Recurring Seasonal Cycle of Glacier Calving Styles and Patterns

Drivers of Recurring Seasonal Cycle of Glacier Calving Styles and Patterns

Calving of a Large Greenlandic Tidewater Glacier has Complex Links to Meltwater Plumes and Mélange

Contribution of calving to frontal ablation quantified from seismic and hydroacoustic observations calibrated with lidar volume measurements

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