scholarly journals Calving controlled by melt-under-cutting: detailed calving styles revealed through time-lapse observations

2019 ◽  
Vol 60 (78) ◽  
pp. 20-31 ◽  
Author(s):  
Penelope How ◽  
Kristin M. Schild ◽  
Douglas I. Benn ◽  
Riko Noormets ◽  
Nina Kirchner ◽  
...  
Keyword(s):  
Tidal Cycle ◽  
Time Lapse ◽  
Prognostic Models ◽  
Small Scale ◽  
Cycle Plays ◽  
Tidewater Glacier ◽  
Glacier Front ◽  
Detailed Record ◽  
Frontal Ablation

AbstractWe present a highly detailed study of calving dynamics at Tunabreen, a tidewater glacier in Svalbard. A time-lapse camera was trained on the terminus and programmed to capture images every 3 seconds over a 28-hour period in August 2015, producing a highly detailed record of 34 117 images from which 358 individual calving events were distinguished. Calving activity is characterised by frequent events (12.8 events h−1) that are small relative to the spectrum of calving events observed, demonstrating the prevalence of small-scale calving mechanisms. Five calving styles were observed, with a high proportion of calving events (82%) originating at, or above, the waterline. The tidal cycle plays a key role in the timing of calving events, with 68% occurring on the falling limb of the tide. Calving activity is concentrated where meltwater plumes surface at the glacier front, and a ~ 5 m undercut at the base of the glacier suggests that meltwater plumes encourage melt-under-cutting. We conclude that frontal ablation at Tunabreen may be paced by submarine melt rates, as suggested from similar observations at glaciers in Svalbard and Alaska. Using submarine melt rate to calculate frontal ablation would greatly simplify estimations of tidewater glacier losses in prognostic models.

scholarly journals A two-dimensional glacier–fjord coupled model applied to estimate submarine melt rates and front position changes of Hansbreen, Svalbard

2018 ◽  
Vol 64 (247) ◽  
pp. 745-758 ◽  
Author(s):  
E. DE ANDRÉS ◽  
J. OTERO ◽  
F. NAVARRO ◽  
A. PROMIŃSKA ◽  
J. LAPAZARAN ◽  
...  
Keyword(s):  
Coupled Model ◽  
Small Scale ◽  
Two Dimensional ◽  
Time Step ◽  
Software Packages ◽  
Front Position ◽  
Circulation Patterns ◽  
Glacier Front ◽  
Order Of Magnitude ◽  
Frontal Ablation

ABSTRACTWe have developed a two-dimensional coupled glacier–fjord model, which runs automatically using Elmer/Ice and MITgcm software packages, to investigate the magnitude of submarine melting along a vertical glacier front and its potential influence on glacier calving and front position changes. We apply this model to simulate the Hansbreen glacier–Hansbukta proglacial–fjord system, Southwestern Svalbard, during the summer of 2010. The limited size of this system allows us to resolve some of the small-scale processes occurring at the ice–ocean interface in the fjord model, using a 0.5 s time step and a 1 m grid resolution near the glacier front. We use a rich set of field data spanning the period April–August 2010 to constrain, calibrate and validate the model. We adjust circulation patterns in the fjord by tuning subglacial discharge inputs that best match observed temperature while maintaining a compromise with observed salinity, suggesting a convectively driven circulation in Hansbukta. The results of our model simulations suggest that both submarine melting and crevasse hydrofracturing exert important controls on seasonal frontal ablation, with submarine melting alone not being sufficient for reproducing the observed patterns of seasonal retreat. Both submarine melt and calving rates accumulated along the entire simulation period are of the same order of magnitude, ~100 m. The model results also indicate that changes in submarine melting lag meltwater production by 4–5 weeks, which suggests that it may take up to a month for meltwater to traverse the englacial and subglacial drainage network.

scholarly journals Large spatial variations in the flux balance along the front of a Greenland tidewater glacier

2019 ◽  
Vol 13 (3) ◽  
pp. 911-925 ◽  
Author(s):  
Till J. W. Wagner ◽  
Fiamma Straneo ◽  
Clark G. Richards ◽  
Donald A. Slater ◽  
Laura A. Stevens ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Variability ◽  
Ocean Model ◽  
Complex Interplay ◽  
Flux Balance ◽  
Tidewater Glacier ◽  
Glacier Front ◽  
The Individual ◽  
High Spatial Variability ◽  
Frontal Ablation

Abstract. The frontal flux balance of a medium-sized tidewater glacier in western Greenland in the summer is assessed by quantifying the individual components (ice flux, retreat, calving, and submarine melting) through a combination of data and models. Ice flux and retreat are obtained from satellite data. Submarine melting is derived using a high-resolution ocean model informed by near-ice observations, and calving is estimated using a record of calving events along the ice front. All terms exhibit large spatial variability along the ∼5 km wide ice front. It is found that submarine melting accounts for much of the frontal ablation in small regions where two subglacial discharge plumes emerge at the ice front. Away from the subglacial plumes, the estimated melting accounts for a small fraction of frontal ablation. Glacier-wide, these estimates suggest that mass loss is largely controlled by calving. This result, however, is at odds with the limited presence of icebergs at this calving front – suggesting that melt rates in regions outside of the subglacial plumes may be underestimated. Finally, we argue that localized melt incisions into the glacier front can be significant drivers of calving. Our results suggest a complex interplay of melting and calving marked by high spatial variability along the glacier front.

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

2019 ◽  
Author(s):  
Andreas Köhler ◽  
Michał Pętlicki ◽  
Pierre-Marie Lefeuvre ◽  
Giuseppa Buscaino ◽  
Christopher Nuth ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Seismic Station ◽  
Time Lapse ◽  
High Temporal Resolution ◽  
Tidewater Glaciers ◽  
Relative Contribution ◽  
Glacier Front ◽  
Volume Measurements ◽  
Seismic Records ◽  
Frontal Ablation

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 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 150–350 m a−1). This study shows the feasibility to seismically monitor not only frontal ablation rates but also its dynamic ice loss contribution continuously and at high temporal resolution.

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

2019 ◽  
Vol 13 (11) ◽  
pp. 3117-3137 ◽  
Author(s):  
Andreas Köhler ◽  
Michał Pętlicki ◽  
Pierre-Marie Lefeuvre ◽  
Giuseppa Buscaino ◽  
Christopher Nuth ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Time Lapse ◽  
High Temporal Resolution ◽  
Tidewater Glaciers ◽  
Relative Contribution ◽  
Glacier Front ◽  
Volume Measurements ◽  
Seismic Records ◽  
Frontal Ablation

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.

Study of Thermal Activity in The Mixing Layer During First Generated Single Cloud by Using Combined Observation From Boundary Layer Radar, Doppler Lidar and Time Lapse Camera 

2021 ◽  
Author(s):  
Ginaldi Ari Nugroho ◽  
Kosei Yamaguchi ◽  
Eiichi Nakakita ◽  
Masayuki K. Yamamoto ◽  
Seiji Kawamura ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Time Series ◽  
Atmospheric Boundary Layer ◽  
Vertical Velocity ◽  
Time Lapse ◽  
Small Scale ◽  
Thermal Activity ◽  
Doppler Lidar ◽  
Cumulus Cloud ◽  
Scale Perturbation

<p>Detailed observation of small scale perturbation in the atmospheric boundary layer during the first generated cumulus cloud are conducted. Our target is to study this small scale perturbation, especially related to the thermal activity at the first generated cumulus cloud. The observation is performed during the daytime on August 17, 2018, and September 03, 2018. Location is focused in the urban area of Kobe, Japan. High-resolution instruments such as Boundary Layer Radar, Doppler Lidar, and Time Lapse camera are used in this observation. Boundary Layer Radar, and Doppler Lidar are used for clear air observation. Meanwhile Time Lapse Camera are used for cloud existence observation. The atmospheric boundary layer structure is analyzed based on vertical velocity profile, variance, skewness, and estimated atmospheric boundary layer height. Wavelet are used to observe more of the period of the thermal activity. Furthermore, time correlation between vertical velocity time series from height 0.3 to 2 km and image pixel of generated cloud time series are also discussed in this study.</p>

scholarly journals Short-term post-mortality scavenging and longer term recovery after anoxia in the northern Adriatic Sea

2013 ◽  
Vol 10 (11) ◽  
pp. 7647-7659 ◽  
Author(s):  
M. Blasnig ◽  
B. Riedel ◽  
L. Schiemer ◽  
M. Zuschin ◽  
M. Stachowitsch
Keyword(s):  
Adriatic Sea ◽  
Time Lapse ◽  
Hermit Crabs ◽  
Small Scale ◽  
Short Term ◽  
Northern Adriatic Sea ◽  
Northern Adriatic ◽  
Hexaplex Trunculus ◽  
Distinct Sequence ◽  
And Function

Abstract. The northern Adriatic Sea is one of nearly 500 areas worldwide suffering widespread mortalities due to anoxia. The present study documents post-anoxia macrofauna dynamics after experimentally inducing small-scale anoxia in 24 m depth (2 plots, each 50 cm × 50 cm). Time-lapse camera deployments examined short-term scavenging of the moribund and dead organisms (multi-species clumps consisting of sponges and ascidians) over two 3-day periods (August 2009: 71.5 h, September 2009: 67.5 h). Longer term recovery (days to 2 yr) in the same two plots was examined with an independent photo series. Scavengers arrived quickly and in a distinct sequence: demersal (Gobius niger, Serranus hepatus) and benthopelagic fishes (Diplodus vulgaris, Pagellus erythrinus), followed by hermit crabs (Paguristes eremita, showing a clear day/night rhythm in presence) and gastropods (Hexaplex trunculus). This sequence is attributed to the relative speeds and densities of the organisms. The sessile fauna was largely removed or consumed within seven (August plot) and 13 (September plot) days after anoxia, confirming our first hypothesis that decaying organisms are quickly utilised. The scavengers remained in dense aggregations (e.g. up to 33 P. eremita individuals at one time) as long as dead organisms were available. No recovery of sessile macroepibenthos macroepibenthos occurred in the experimental plots one and two years after anoxia, undermining our second hypothesis that small denuded areas are more rapidly recolonised. This study underlines the sensitivity of this soft-bottom community and supports calls for reducing additional anthropogenic disturbances such as fishing practices that further impede recolonisation and threaten benthic community structure and function over the long term.

scholarly journals Closing the mass budget of a tidewater glacier: the example of Kronebreen, Svalbard

2019 ◽  
Vol 65 (249) ◽  
pp. 136-148 ◽  
Author(s):  
CESAR DESCHAMPS-BERGER ◽  
CHRISTOPHER NUTH ◽  
WARD VAN PELT ◽  
ETIENNE BERTHIER ◽  
JACK KOHLER ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Mass Balance ◽  
Total Mass ◽  
Continuity Equation ◽  
Recent Period ◽  
Mass Budget ◽  
Tidewater Glacier ◽  
Geodetic Mass Balance ◽  
Frontal Ablation

ABSTRACTIn this study, we combine remote sensing, in situ and model-derived datasets from 1966 to 2014 to calculate the mass-balance components of Kronebreen, a fast-flowing tidewater glacier in Svalbard. For the well-surveyed period 2009–2014, we are able to close the glacier mass budget within the prescribed errors. During these 5 years, the glacier geodetic mass balance was −0.69 ± 0.12 m w.e. a−1, while the mass budget method led to a total mass balance of −0.92 ± 0.16 m w.e. a−1, as a consequence of a strong frontal ablation (−0.78 ± 0.11 m w.e. a−1), and a slightly negative climatic mass balance (−0.14 ± 0.11 m w.e. a−1). The trend towards more negative climatic mass balance between 1966–1990 (+0.20 ± 0.05 m w.e. a−1) and 2009–2014 is not reflected in the geodetic mass balance trend. Therefore, we suspect a reduction in ice-discharge in the most recent period. Yet, these multidecadal changes in ice-discharge cannot be measured from the available observations and thus are only estimated with relatively large errors as a residual of the mass continuity equation. Our study presents the multidecadal evolution of the dynamics and mass balance of a tidewater glacier and illustrates the errors introduced by inferring one unmeasured mass-balance component from the others.

scholarly journals Spatially distributed runoff at the grounding line of a large Greenlandic tidewater glacier inferred from plume modelling

2017 ◽  
Vol 63 (238) ◽  
pp. 309-323 ◽  
Author(s):  
DONALD SLATER ◽  
PETER NIENOW ◽  
ANDREW SOLE ◽  
TOM COWTON ◽  
RUTH MOTTRAM ◽  
...  
Keyword(s):  
General Circulation ◽  
Circulation Model ◽  
Time Lapse ◽  
Atmospheric Temperature ◽  
Recent Change ◽  
Grounding Line ◽  
Tidewater Glacier ◽  
Spatially Distributed ◽  
Basal Sliding ◽  
Catchment Runoff

ABSTRACTUnderstanding the drivers of recent change at Greenlandic tidewater glaciers is of great importance if we are to predict how these glaciers will respond to climatic warming. A poorly constrained component of tidewater glacier processes is the near-terminus subglacial hydrology. Here we present a novel method for constraining near-terminus subglacial hydrology with application to marine-terminating Kangiata Nunata Sermia in South-west Greenland. By simulating proglacial plume dynamics using buoyant plume theory and a general circulation model, we assess the critical subglacial discharge, if delivered through a single compact channel, required to generate a plume that reaches the fjord surface. We then compare catchment runoff to a time series of plume visibility acquired from a time-lapse camera. We identify extended periods throughout the 2009 melt season where catchment runoff significantly exceeds the discharge required for a plume to reach the fjord surface, yet we observe no plume. We attribute these observations to spatial spreading of runoff across the grounding line. Persistent distributed drainage near the terminus would lead to more spatially homogeneous submarine melting and may promote more rapid basal sliding during warmer summers, potentially providing a mechanism independent of ocean forcing for increases in atmospheric temperature to drive tidewater glacier acceleration.

scholarly journals The terminus of Hubbard Glacier, Alaska

1992 ◽  
Vol 16 ◽  
pp. 151-157 ◽  
Author(s):  
Robert M. Krimmel ◽  
D. C. Trabant
Keyword(s):  
Seasonal Variation ◽  
Tidal Current ◽  
Time Lapse ◽  
Seasonal Fluctuations ◽  
Seasonal Differences ◽  
Long Period ◽  
Short Period ◽  
Length Changes ◽  
Detailed Record ◽  
Seasonal Length

Hubbard Glacier advanced across the entrance of Russell Fiord in May 1986, transforming the fiord into a lake, which began filling with fresh water. The dam failed in October 1986. The calving terminus of Hubbard Glacier has been mapped with increasing frequency for nearly a century. A mapping interval of a few years establishes that the terminus has made a slow, but accelerating, advance. Recently the terminus has been mapped several times per month using vertical photography, ground surveys, and time-lapse cameras. At this frequency of observation, the terminus position is found to fluctuate seasonally. These seasonal fluctuations are compared with those of Columbia Glacier, where a longer detailed record is available. Although Columbia Glacier is now undergoing a drastic retreat, it continues to have seasonal length changes similar to those it experienced before the retreat began. The lengths of both Columbia and Hubbard Glaciers are extended in the spring, and retracted in the fall. The relatively long period of record for Columbia Glacier shows consistent seasonal variation in length and, when compared with the short period of record for Hubbard Glacier, suggests that there are consistent seasonal differences in length at Hubbard also. The lower Hubbard Glacier diverges, feeding ice into Disenchantment Bay and Russell Fiord, and advances and retreats synchronously over most of its width. The tidal current, which passes through the 250–500 m wide entrance to Russell Fiord, does not affect the seasonal advance and retreat in that area significantly.

scholarly journals Open-source personal pipetting robots with live-cell incubation and microscopy compatibility

2021 ◽  
Author(s):  
Philip Dettinger ◽  
Tobias Kull ◽  
Geethika Arekatla ◽  
Nouraiz Ahmed ◽  
Yang Zhang ◽  
...  
Keyword(s):  
Open Source ◽  
Time Lapse ◽  
Small Scale ◽  
Liquid Handling ◽  
Academic Settings ◽  
Stem And Progenitor Cells ◽  
Cell Incubation ◽  
Self Production ◽  
Liquid Handling Robot ◽  
Laboratory Member

Liquid handling robots have the potential to automate many procedures in life sciences. However, they are not in widespread use in academic settings, where funding, space and maintenance specialists are usually limiting. In addition, current robots require lengthy programming by specialists and are incompatible with most academic laboratories with constantly changing small-scale projects. Here, we present the Pipetting Helper Imaging Lid (PHIL), an inexpensive, small, open-source personal liquid handling robot. It is designed for inexperienced users, with self-production from cheap commercial and 3D-printable components and custom control software. PHIL successfully automated pipetting for e.g. tissue immunostainings and stimulations of live stem and progenitor cells during time-lapse microscopy. PHIL is cheap enough for any laboratory member to have their own personal pipetting robot(s), and enables users without programming skills to easily automate a large range of experiments.

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