@article {336, title = {Circumpolar Deep Water Impacts Glacial Meltwater Export and Coastal Biogeochemical Cycling Along the West Antarctic Peninsula}, journal = {Frontiers in Marine Science}, volume = {6}, year = {2019}, pages = {1{\textendash}23}, keywords = {Antarctic Peninsula, ice, meltwater, phytoplankton}, issn = {2296-7745}, doi = {10.3389/fmars.2019.00144}, url = {https://www.frontiersin.org/article/10.3389/fmars.2019.00144/full}, author = {Cape, Mattias R. and Vernet, Maria and Pettit, Erin C. and Wellner, Julia and Truffer, Martin and Akie, Garrett and Domack, Eugene and Leventer, Amy and Smith, Craig R. and Huber, Bruce A.} } @article {Aschwanden2019, title = {{Contribution of the Greenland Ice Sheet to sea level over the next millennium}}, journal = {Science Advances}, volume = {5}, number = {6}, year = {2019}, month = {jun}, pages = {eaav9396}, abstract = {The Greenland Ice Sheet holds 7.2 m of sea level equivalent and in recent decades, rising temperatures have led to accelerated mass loss. Current ice margin recession is led by the retreat of outlet glaciers, large rivers of ice ending in narrow fjords that drain the interior. We pair an outlet glacier{\textendash}resolving ice sheet model with a comprehensive uncertainty quantification to estimate Greenland{\textquoteright}s contribution to sea level over the next millennium. We find that Greenland could contribute 5 to 33 cm to sea level by 2100, with discharge from outlet glaciers contributing 8 to 45\% of total mass loss. Our analysis shows that uncertainties in projecting mass loss are dominated by uncertainties in climate scenarios and surface processes, whereas uncertainties in calving and frontal melt play a minor role. We project that Greenland will very likely become ice free within a millennium without substantial reductions in greenhouse gas emissions.}, issn = {2375-2548}, doi = {10.1126/sciadv.aav9396}, url = {http://advances.sciencemag.org/lookup/doi/10.1126/sciadv.aav9396}, author = {Aschwanden, Andy and Fahnestock, Mark A. and Truffer, Martin and Brinkerhoff, Douglas J. and Hock, Regine and Khroulev, Constantine and Mottram, Ruth and Khan, S. Abbas} } @article {333, title = {The Larsen Ice Shelf System, Antarctica (LARISSA): Polar Systems Bound Together, Changing Fast}, journal = {GSA Today}, volume = {29}, year = {2019}, pages = {4{\textendash}10}, abstract = {Climatic, cryospheric, and biologic changes taking place in the northern Antarctic Peninsula provide examples for how ongoing systemic change may pro- gress through the entire Antarctic system. A large, interdisciplinary research project focused on the Larsen Ice Shelf system, synthesized here, has documented dramatic ice cover, oceanographic, and ecosystem changes in the Antarctic Peninsula during the Holocene and the present period of rapid regional warming. The responsive- ness of the region results from its position in the climate and ocean system, in which a narrow continental block extends across zonal atmospheric and ocean flow, creating high snow accumulation, strong gradients and gyres, dynamic oceanography, outlet glaciers feeding into many fjords and bays having steep topography, and a continental shelf that contains many glacially carved troughs separated by areas of glacial sedi- ment accumulation. The microcosm of the northern Antarctic Peninsula has a ten- dency to change rapidly{\textemdash}rapid relative not just to Antarctica{\textquoteright}s mainland but compared to the rest of the planet as well{\textemdash}and it is generally warmer than the rest of Antarctica. Both its Holocene and modern glaciological retreats offer a picture of how larger areas of Antarctica farther south might change under future warming.}, issn = {10525173}, doi = {10.1130/gsatg382a.1}, author = {Wellner, Julia and Scambos, Ted and Domack, Eugene and Vernet, Maria and Leventer, Amy and Balco, Greg and Brachfeld, Stefanie and Cape, Mattias and Huber, Bruce and Ishman, Scott and McCormick, Michael and Mosley-Thompson, Ellen and Pettit, Erin and Smith, Craig and Truffer, Martin and Van Dover, Cindy and Yoo, Kyu-Cheul} } @article {337, title = {Non-linear glacier response to calving events, Jakobshavn Isbr{\ae}, Greenland}, journal = {Journal of Glaciology}, volume = {65}, year = {2019}, pages = {39{\textendash}54}, abstract = {Jakobshavn Isbr{\ae}, a tidewater glacier that produces some of Greenland{\textquoteright}s largest icebergs and highest speeds, reached record-high flow rates in 2012 (Joughin and others, 2014). We use terrestrial radar interferometric observations from August 2012 to characterize the events that led to record-high flow. We find that the highest speeds occurred in response to a small calving retreat, while several larger calving events produced negligible changes in glacier speed. This non-linear response to calving events suggests the terminus was close to flotation and therefore highly sensitive to terminus position. Our observations indicate that a glacier{\textquoteright}s response to calving is a consequence of two competing feedbacks: (1) an increase in strain rates that leads to dynamic thinning and faster flow, thereby promoting destabilization, and (2) an increase in flow rates that advects thick ice toward the terminus and promotes restabilization. The competition between these feedbacks depends on temporal and spatial variations in the glacier{\textquoteright}s proximity to flotation. This study highlights the importance of dynamic thinning and advective processes on tidewater glacier stability, and further suggests the latter may be limiting the current retreat due to the thick ice that occupies Jakobshavn Isbr{\ae}{\textquoteright}s retrograde bed.}, keywords = {calving, dynamic thinning, Jakobshavn Isbr{\ae}, terrestrial radar interferometry, tidewater glaciers}, issn = {00221430}, doi = {10.1017/jog.2018.90}, author = {Cassotto, Ryan and Fahnestock, Mark and Amundson, Jason M. and Truffer, Martin and Boettcher, Margaret S. and De La Pe{\~n}a, Santiago and Howat, Ian} } @article {alexander_simulated_2019, title = {Simulated {Greenland} {Surface} {Mass} {Balance} in the {GISS} {ModelE2} {GCM}: {Role} of the {Ice} {Sheet} {Surface}}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {124}, number = {3}, year = {2019}, pages = {750{\textendash}765}, abstract = {The rate of growth or retreat of the Greenland and Antarctic ice sheets remains a highly uncertain component of future sea level change. Here we examine the simulation of Greenland ice sheet surface mass balance (GrIS SMB) in a development branch of the ModelE2 version of the NASA Goddard Institute for Space Studies (GISS) general circulation model (GCM). GCMs are often limited in their ability to represent SMB compared with polar region regional climate models. We compare ModelE2-simulated GrIS SMB for present-day (1996{\textendash}2005) simulations with fixed ocean conditions, at a spatial resolution of 2{\textdegree} latitude by 2.5{\textdegree} longitude ({\textasciitilde}200 km), with SMB simulated by the Mod{\`e}le Atmosph{\'e}rique R{\'e}gionale (MAR) regional climate model (1996{\textendash}2005 at a 25-km resolution). ModelE2 SMB agrees well with MAR SMB on the whole, but there are distinct spatial patterns of differences and large differences in some SMB components. The impacts of changes to the ModelE2 surface are tested, including a subgrid-scale representation of SMB with surface elevation classes. This has a minimal effect on ice sheet-wide SMB but corrects local biases. Replacing fixed surface albedo with satellite-derived values and an age-dependent scheme has a larger impact, increasing simulated melt by 60\%{\textendash}100\%. We also find that lower surface albedo can enhance the effects of elevation classes. Reducing ModelE2 surface roughness length to values closer to MAR reduces sublimation by {\textasciitilde}50\%. Further work is required to account for meltwater refreezing in ModelE2 and to understand how differences in atmospheric processes and model resolution influence simulated SMB. Plain Language Summary Melting of the Earth{\textquoteright}s ice sheets represents a substantial contribution to global sea level rise. Global climate model simulations of Earth{\textquoteright}s climate often model the surface of ice sheets in a fairly simple way because of computational limitations. This study evaluates the representation of the Greenland ice sheet in one such global model simulation (from the NASA Goddard Institute for Space Studies general circulation model) against a regional model that simulates only the local Greenland area in a higher degree of detail. The study finds that the global model simulation of the Greenland ice sheet is sensitive to how the model represents the ice sheet surface, in particular, how it reflects incoming sunlight, stores and freezes liquid water, and simulates surface evaporation. Attempting to improve the simulation by dividing the ice sheet surface into additional grid cells according to surface elevation has a minor impact on the simulation. The study reveals how the representation of the Greenland ice sheet in ModelE2 might be improved to better estimate ice sheet change and the sea level response to global climate changes.}, keywords = {1911-UW}, issn = {2169-9003, 2169-9011}, doi = {10.1029/2018JF004772}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JF004772}, author = {Alexander, P. M. and LeGrande, A. N. and Fischer, E. and Tedesco, M. and Fettweis, X. and Kelley, M. and Nowicki, S. M. J. and Schmidt, G. A.} } @article {334, title = {Spatio-temporal variations in seasonal ice tongue submarine melt rate at a tidewater glacier in southwest Greenland}, journal = {J. Glaciol.}, year = {2019}, pages = {1{\textendash}8}, keywords = {glacier calving, ice, ocean interactions, Remote sensing, subglacial processes}, doi = {10.1017/jog.2019.27}, author = {Moyer, A N and Nienow, P W and Gourmelen, N and Sole, A J and Truffer, M and Fahnestock, M and Slater, D A} } @article {335, title = {Tracking icebergs with time-lapse photography and sparse optical flow , LeConte Bay , Alaska , 2016 {\textendash} 2017}, journal = {J. Glaciol.}, volume = {65}, year = {2019}, pages = {195{\textendash}211}, keywords = {glaciological instruments and methods, ice, icebergs, ocean interactions, Remote sensing}, doi = {10.1017/jog.2018.105}, author = {Kienholz, Christian and Amundson, Jason M and Motyka, Roman J and Jackson, Rebecca H and Mickett, John B and Sutherland, David A and Nash, Jonathan D and Winters, Dylan S and Dryer, William P and Truffer, Martin} } @article {oct, title = {Active seismic studies in valley glacier settings: strategies and limitations}, journal = {Journal of Glaciology}, volume = {64}, year = {2018}, month = {oct}, pages = {796{\textendash}810}, abstract = {Subglacial tills play an important role in glacier dynamics but are difficult to characterize in situ. Amplitude Variation with Angle (AVA) analysis of seismic reflection data can distinguish between stiff tills and deformable tills. However, AVA analysis in mountain glacier environments can be problematic: reflections can be obscured by Rayleigh wave energy scattered from crevasses, and complex basal topography can impede the location of reflection points in 2-D acquisitions. We use a forward model to produce challenging synthetic seismic records in order to test the efficacy of AVA in crevassed and geometrically complex environments. We find that we can distinguish subglacial till types in moderately crevassed environments, where {\textquoteleft}moderate{\textquoteright} depends on crevasse spacing and orientation. The forward model serves as a planning tool, as it can predict AVA success or failure based on characteristics of the study glacier. Applying lessons from the forward model, we perform AVA on a seismic dataset collected from Taku Glacier in Southeast Alaska in March 2016. Taku Glacier is a valley glacier thought to overlay thick sediment deposits. A near-offset polarity reversal confirms that the tills are deformable.}, keywords = {glacial tills, glacier geophysics, glaciological instruments and methods, seismics, subglacial}, issn = {0022-1430}, doi = {10.1017/jog.2018.69}, url = {https://www.cambridge.org/core/product/identifier/S0022143018000692/type/journal{\_}article}, author = {ZECHMANN, JENNA M. and BOOTH, ADAM D. and Truffer, Martin and Gusmeroli, Alessio and Amundson, Jason M. and Larsen, Christopher F.} } @article {344, title = {Acquisition of a 3 min, two-dimensional glacier velocity field with terrestrial radar interferometry}, journal = {Journal of Glaciology}, year = {2017}, pages = {1{\textendash}8}, abstract = {{\textless}p{\textgreater}Outlet glaciers undergo rapid spatial and temporal changes in flow velocity during calving events. Observing such changes requires both high temporal and high spatial resolution methods, something now possible with terrestrial radar interferometry. While a single such radar provides line-of-sight velocity, two radars define both components of the horizontal flow field. To assess the feasibility of obtaining the two-dimensional (2-D) flow field, we deployed two terrestrial radar interferometers at Jakobshavn Isbrae, a major outlet glacier on Greenland{\textquoteright}s west coast, in the summer of 2012. Here, we develop and demonstrate a method to combine the line-of-sight velocity data from two synchronized radars to produce a 2-D velocity field from a single (3 min) interferogram. Results are compared with the more traditional feature-tracking data obtained from the same radar, averaged over a longer period. We demonstrate the potential and limitations of this new dual-radar approach for obtaining high spatial and temporal resolution 2-D velocity fields at outlet glaciers.{\textless}/p{\textgreater}}, keywords = {glacier flow, glacier geophysics, glaciological instruments and methods}, issn = {0022-1430}, doi = {10.1017/jog.2017.28}, url = {https://www.cambridge.org/core/product/identifier/S0022143017000284/type/journal{\_}article}, author = {Voytenko, Denis and Dixon, Timothy H. and Holland, David M. and Cassotto, Ryan and Howat, Ian M. and Fahnestock, Mark A. and Truffer, Martin and De La Pe{\~n}a, Santiago} } @article {apr, title = {Asynchronous behavior of outlet glaciers feeding Godth{\aa}bsfjord (Nuup Kangerlua) and the triggering of Narsap Sermia{\textquoteright}s retreat in SW Greenland}, journal = {J. Glaciol.}, volume = {63}, year = {2017}, month = {apr}, pages = {288{\textendash}308}, abstract = {We assess ice loss and velocity changes between 1985 and 2014 of three tidewater and five-land terminating glaciers in Godth{\aa}bsfjord (Nuup Kangerlua), Greenland. Glacier thinning accounted for 43.8 {\textpm} 0.2 km 3 of ice loss, equivalent to 0.10 mm eustatic sea-level rise. An additional 3.5 {\textpm} 0.3 km 3 was lost to the calving retreats of Kangiata Nunaata Sermia (KNS) and Narsap Sermia (NS), two tidewater glaciers that exhibited asynchronous behavior over the study period. KNS has retreated 22 km from its Little Ice Age (LIA) maximum (1761 AD), of which 0.8 km since 1985. KNS has stabilized in shallow water, but seasonally advects a 2 km long floating tongue. In contrast, NS began retreating from its LIA moraine in 2004{\textendash}06 (0.6 km), re-stabilized, then retreated 3.3 km during 2010{\textendash}14 into an over-deepened basin. Velocities at KNS ranged 5{\textendash}6 km a -1 , while at NS they increased from 1.5 to 5.5 km a -1 between 2004 and 2014. We present comprehensive analyses of glacier thinning, runoff, surface mass balance, ocean conditions, submarine melting, bed topography, ice m{\'e}lange and conclude that the 2010{\textendash}14 NS retreat was triggered by a combination of factors but primarily by an increase in submarine melting.}, keywords = {glacier calving, glacier discharge, glacier mass balance, ice/atmosphere interactions, ice/ocean interactions, tidewater glaciers}, issn = {0022-1430}, doi = {10.1017/jog.2016.138}, author = {Motyka, Roman J. and Cassotto, Ryan and Truffer, Martin and Kjeldsen, Kristian K. and Van As, Dirk and Korsgaard, Niels J. and Fahnestock, Mark and Howat, Ian and Langen, Peter L. and Mortensen, John and Lennert, Kunuk and Rysgaard, S{\o}ren} } @article {dec, title = {Error sources in basal yield stress inversions for Jakobshavn Isbr{\ae}, Greenland, derived from residual patterns of misfit to observations}, journal = {Journal of Glaciology}, volume = {63}, year = {2017}, month = {dec}, pages = {999{\textendash}1011}, abstract = {The basal interface of glaciers is generally not directly observable. Geophysical inverse methods are therefore used to infer basal parameters from surface observations. Such methods can also provide information about potential inadequacies of the forward model. Ideally an inverse problem can be regularized so that the differences between modeled and observed surface velocities reflect observational errors. However, deficiencies in the forward model usually result in additional errors. Here we use the spatial pattern of velocity residuals to discuss the main error sources for basal stress inversions for Jakobshavn Isbr{\ae}, Greenland. Synthetic tests with prescribed patterns of basal yield stress with varying length scales are then used to investigate different weighting functions for the data-model misfit and for the ability of the inversion to resolve details in basal yield stress. We also test real-data inversions for their sensitivities to prior estimate, forward model parameters, data gaps, and temperature fields. We find that velocity errors are not sufficient to explain the residual patterns of real-data inversions. Conversely, ice-geometry errors and especially simulated errors in model simplifications are capable of reproducing similar error patterns and magnitudes. We suggest that residual patterns can provide useful guidance for forward model improvements.}, keywords = {glacier modeling, ice-sheet modeling, subglacial processes}, issn = {0022-1430}, doi = {10.1017/jog.2017.61}, url = {https://www.cambridge.org/core/product/identifier/S0022143017000612/type/journal{\_}article}, author = {Habermann, Marijke and Truffer, Martin and Maxwell, David} } @article {311, title = {Mass Balance Evolution of Black Rapids Glacier, Alaska, 1980{\textendash}2100, and Its Implications for Surge Recurrence}, journal = {Frontiers in Earth Science}, volume = {5}, year = {2017}, pages = {56}, abstract = {Surge-type Black Rapids Glacier, Alaska, has undergone strong retreat since it last surged in 1936-37. To assess its evolution during the late 20th and 21st centuries and determine potential implications for surge likelihood, we run a simplified glacier model over the periods 1980-2015 (hindcasting) and 2015-2100 (forecasting). The model is forced by daily temperature and precipitation fields, with downscaled reanalysis data used for the hindcasting. A constant climate scenario and an RCP 8.5 scenario based on the GFDL-CM3 climate model are employed for the forecasting. Debris evolution is accounted for by a debris layer time series derived from satellite imagery (hindcasting) and a parametrized debris evolution model (forecasting). A retreat model accounts for the evolution of the glacier geometry. Model calibration, validation and parametrization rely on an extensive set of in situ and remotely sensed observations. To explore uncertainties in our projections, we run the glacier model in a Monte Carlo fashion, varying key model parameters and input data within plausible ranges. Our results for the hindcasting period indicate a negative mass balance trend, caused by atmospheric warming in the summer, precipitation decrease in the winter and surface elevation lowering (climate-elevation feedback), which exceed the moderating effects from increasing debris cover and glacier retreat. Without the 2002 rockslide deposits on Black Rapids{\textquoteright} lower reaches, the mass balances would be more negative, by ~20\% between the 2003 and 2015 mass-balance years. Despite its retreat, Black Rapids Glacier is substantially out of balance with the current climate. By 2100, ~8\% of Black Rapids{\textquoteright} 1980 area are projected to vanish under the constant climate scenario and ~73\% under the RCP 8.5 scenario. For both scenarios, the remaining glacier portions are out of balance, suggesting continued retreat after 2100. Due to mass starvation, a surge in the 21st century is unlikely. The projected retreat will affect the glacier{\textquoteright}s runoff and change the landscape in the Black Rapids area markedly.}, issn = {2296-6463}, doi = {10.3389/feart.2017.00056}, url = {http://journal.frontiersin.org/article/10.3389/feart.2017.00056}, author = {Kienholz, Christian and Hock, Regine and Truffer, Martin and Bieniek, Peter and Lader, Richard} } @article {2017/07/21, title = {Sediment transport drives tidewater glacier periodicity}, volume = {8}, year = {2017}, month = {2017/07/21}, pages = {90}, abstract = {Most of Earth{\textquoteright}s glaciers are retreating, but some tidewater glaciers are advancing despite increasing temperatures and contrary to their neighbors. This can be explained by the coupling of ice and sediment dynamics: a shoal forms at the glacier terminus, reducing ice discharge and causing advance towards an unstable configuration followed by abrupt retreat, in a process known as the tidewater glacier cycle. Here we use a numerical model calibrated with observations to show that interactions between ice flow, glacial erosion, and sediment transport drive these cycles, which occur independent of climate variations. Water availability controls cycle period and amplitude, and enhanced melt from future warming could trigger advance even in glaciers that are steady or retreating, complicating interpretations of glacier response to climate change. The resulting shifts in sediment and meltwater delivery from changes in glacier configuration may impact interpretations of marine sediments, fjord geochemistry, and marine ecosystems.}, isbn = {2041-1723}, url = {https://doi.org/10.1038/s41467-017-00095-5}, author = {Brinkerhoff, Douglas and Truffer, Martin and Aschwanden, Andy} } @article {jan, title = {Sub-ice-shelf sediments record history of twentieth-century retreat of Pine Island Glacier}, journal = {Nature}, volume = {541}, year = {2017}, month = {jan}, pages = {77{\textendash}80}, abstract = {The West Antarctic Ice Sheet is one of the largest potential sources of rising sea levels. Over the past 40 years, glaciers flowing into the Amundsen Sea sector of the ice sheet have thinned at an accelerating rate, and several numerical models suggest that unstable and irreversible retreat of the grounding line{\textemdash}which marks the boundary between grounded ice and floating ice shelf{\textemdash}is underway. Understanding this recent retreat requires a detailed knowledge of grounding-line history, but the locations of the grounding line before the advent of satellite monitoring in the 1990s are poorly dated. In particular, a history of grounding-line retreat is required to understand the relative roles of contemporaneous ocean-forced change and of ongoing glacier response to an earlier perturbation in driving ice-sheet loss. Here we show that the present thinning and retreat of Pine Island Glacier in West Antarctica is part of a climatically forced trend that was triggered in the 1940s. Our conclusions arise from analysis of sediment cores recovered beneath the floating Pine Island Glacier ice shelf, and constrain the date at which the grounding line retreated from a prominent seafloor ridge. We find that incursion of marine water beyond the crest of this ridge, forming an ocean cavity beneath the ice shelf, occurred in 1945 ({\textpm}12 years); final ungrounding of the ice shelf from the ridge occurred in 1970 ({\textpm}4 years). The initial opening of this ocean cavity followed a period of strong warming of West Antarctica, associated with El Ni{\~n}o activity. Thus our results suggest that, even when climate forcing weakened, ice-sheet retreat continued.}, keywords = {Antarctica, Pine Island glacier}, issn = {0028-0836}, doi = {10.1038/nature20136}, url = {http://dx.doi.org/10.1038/nature20136{\%}5Cnhttp://www.nature.com/doifinder/10.1038/nature20136 http://www.nature.com/articles/nature20136}, author = {Smith, J. A. and Andersen, T. J. and Shortt, M. and Gaffney, A. M. and Truffer, Martin and Stanton, T P and Bindschadler, Robert and Dutrieux, Pierre and Jenkins, Adrian and Hillenbrand, C.-D. and Ehrmann, Werner and Corr, H. F. J. and Farley, N. and Crowhurst, S. and Vaughan, David G.} } @article {349, title = {Automated detection of unstable glacier flow and a spectrum of speedup behavior in the Alaska Range}, journal = {Journal of Geophysical Research F: Earth Surface}, volume = {121}, year = {2016}, pages = {64{\textendash}81}, keywords = {automated detection, debris cover, pulse-type glaciers, spectrum of glacier flow instabilities, surge-type glaciers}, issn = {21699011}, doi = {10.1002/2015JF003502}, author = {Herreid, Sam and Truffer, Martin} } @article {Brinkerhoff2016, title = {{Bayesian Inference of Subglacial Topography Using Mass Conservation}}, journal = {Frontiers in Earth Science}, volume = {4}, year = {2016}, month = {feb}, pages = {1{\textendash}27}, abstract = {We develop a Bayesian model for estimating ice thickness given sparse observations coupled with estimates of surface mass balance, surface elevation change, and surface velocity. These fields are related through mass conservation. We use the Metropolis-Hastings algorithm to sample from the posterior probability distribution of ice thickness for three cases: a synthetic mountain glacier, ̈ Storglaci aren, and Jakobshavn Isbr{\ae}. Use of continuity in interpolation improves thickness estimates where relative velocity and surface mass balance errors are small, a condition difficult to maintain in regions of slow flow and surface mass balance near zero. Estimates of thickness uncertainty depend sensitively on spatial correlation. When this structure is known, we suggest a thickness measurement spacing of one to two times the correlation length to take best advantage of continuity based interpolation techniques. To determine ideal measurement spacing, the structure of spatial correlation must be better quantified.}, issn = {2296-6463}, doi = {10.3389/feart.2016.00008}, url = {http://journal.frontiersin.org/article/10.3389/feart.2016.00008}, author = {Brinkerhoff, Douglas J and Aschwanden, Andy and Truffer, Martin} } @article {Aschwanden2016, title = {{Complex Greenland outlet glacier flow captured}}, journal = {Nature Communications}, volume = {7}, year = {2016}, month = {feb}, pages = {10524}, issn = {2041-1723}, doi = {10.1038/ncomms10524}, url = {http://www.nature.com/doifinder/10.1038/ncomms10524}, author = {Aschwanden, Andy and Fahnestock, Mark A and Truffer, Martin} } @article {306, title = {Geodetic mass balance of surge-type Black Rapids Glacier, Alaska, 1980{\textendash}2001{\textendash}2010, including role of rockslide deposition and earthquake displacement}, journal = {Journal of Geophysical Research: Earth Surface}, year = {2016}, author = {Kienholz, C and Hock, R and Truffer, M and Arendt, A and Arko, S} } @article {Brinkerhoffetal2016, title = {Inversion of a glacier hydrology model}, journal = {Ann. Glaciol.}, volume = {57}, number = {72}, year = {2016}, pages = {84{\textendash}95}, doi = {10.1017/aog.2016.3}, author = {D. J. Brinkerhoff and C. R. Meyer and E. Bueler and M. Truffer} } @article {oct, title = {Sensitivity of Pine Island Glacier to observed ocean forcing}, journal = {Geophysical Research Letters}, volume = {43}, year = {2016}, month = {oct}, pages = {10,817{\textendash}10,825}, abstract = {{\textcopyright}2016. American Geophysical Union. All Rights Reserved.We present subannual observations (2009{\textendash}2014) of a major West Antarctic glacier (Pine Island Glacier) and the neighboring ocean. Ongoing glacier retreat and accelerated ice flow were likely triggered a few decades ago by increased ocean-induced thinning, which may have initiated marine ice sheet instability. Following a subsequent 60{\%} drop in ocean heat content from early 2012 to late 2013, ice flow slowed, but by {\textless} 4{\%}, with flow recovering as the ocean warmed to prior temperatures. During this cold-ocean period, the evolving glacier-bed/ice shelf system was also in a geometry favorable to stabilization. However, despite a minor, temporary decrease in ice discharge, the basin-wide thinning signal did not change. Thus, as predicted by theory, once marine ice sheet instability is underway, a single transient high-amplitude ocean cooling has only a relatively minor effect on ice flow. The long-term effects of ocean temperature variability on ice flow, however, are not yet known.}, keywords = {glacier-ocean interactions, Ice Dynamics, ice shelves, ice streams, marine ice sheet instability}, issn = {00948276}, doi = {10.1002/2016GL070500}, url = {http://doi.wiley.com/10.1002/2016GL070500}, author = {Christianson, Knut and Bushuk, Mitchell and Dutrieux, Pierre and Parizek, Byron R. and Joughin, Ian R. and Alley, Richard B. and Shean, David E. and Abrahamsen, E. Povl and Anandakrishnan, Sridhar and Heywood, Karen J. and Kim, Tae-Wan and Lee, Sang Hoon and Nicholls, Keith and Stanton, Tim and Truffer, Martin and Webber, Benjamin G. M. and Jenkins, Adrian and Jacobs, Stan and Bindschadler, Robert and Holland, David M.} } @article {348, title = {The taphonomy of human remains in a glacial environment}, journal = {Forensic Science International}, volume = {261}, year = {2016}, pages = {161.e1{\textendash}161.e8}, abstract = {A glacial environment is a unique setting that can alter human remains in characteristic ways. This study describes glacial dynamics and how glaciers can be understood as taphonomic agents. Using a case study of human remains recovered from Colony Glacier, Alaska, a glacial taphonomic signature is outlined that includes: (1) movement of remains, (2) dispersal of remains, (3) altered bone margins, (4) splitting of skeletal elements, and (5) extensive soft tissue preservation and adipocere formation. As global glacier area is declining in the current climate, there is the potential for more materials of archaeological and medicolegal significance to be exposed. It is therefore important for the forensic anthropologist to have an idea of the taphonomy in this setting and to be able to differentiate glacial effects from other taphonomic agents.}, keywords = {Forensic anthropology, Glacial dynamics, Glacial movement, Glacial taphonomy}, issn = {18726283}, doi = {10.1016/j.forsciint.2016.01.027}, url = {http://dx.doi.org/10.1016/j.forsciint.2016.01.027}, author = {Pilloud, Marin A. and Megyesi, Mary S. and Truffer, Martin and Congram, Derek} } @article {Truffer2016, title = {{Where Glaciers Meet Water: Subaqueous Melt and its Relevance to Glaciers in Various Settings}}, journal = {Reviews of Geophysics}, year = {2016}, pages = {n/a{\textendash}n/a}, keywords = {10.1002/2015RG000494 and glaciers, calving, melt, ocean}, issn = {87551209}, doi = {10.1002/2015RG000494}, url = {http://doi.wiley.com/10.1002/2015RG000494}, author = {Truffer, M. and Motyka, Roman} } @article {351, title = {Dynamic jamming of iceberg-choked fjords}, journal = {Geophys. Res. Lett.}, volume = {42}, year = {2015}, pages = {1122{\textendash}1129}, keywords = {10.1002/2014GL062715 and glaciers, calving, icebergs, jamming}, issn = {00948276}, doi = {10.1002/2014GL062715}, author = {Peters, I and Amundson, J. M. and Cassotto, R and Fahnestock, M and Darnell, K and Truffer, M. and Zhang, W.} } @article {253, title = {Run-away thinning of the low elevation {Yakutat Glacier} and its sensitivity to climate change}, journal = {Journal of Glaciology}, volume = {61}, year = {2015}, doi = {10.3189/2015JoG14J125}, author = {Truessel, Barbara and Martin Truffer and Regine Hock and Roman Motyka and Matthias Huss and Jing Zhang} } @article {350, title = {Seasonal and interannual variations in ice melange and its impact on terminus stability, Jakobshavn Isbr{\ae}, Greenland}, journal = {Journal of Glaciology}, volume = {61}, year = {2015}, pages = {76{\textendash}88}, keywords = {arctic glaciology, calving, ice, ocean interactions, Remote sensing, sea-ice dynamics}, issn = {00221430}, doi = {10.3189/2015JoG13J235}, author = {Cassotto, Ryan and Fahnestock, Mark and Amundson, Jason M. and Truffer, Martin and Joughin, Ian} } @article {289, title = {Tidal and seasonal variations in calving flux observed with passive seismology}, journal = {Journal of Geophysical Research: Earth Surface}, year = {2015}, author = {Bartholomaus, Timothy C and Larsen, Christopher F and West, Michael E and O{\textquoteright}Neel, Shad and Pettit, Erin C and Truffer, Martin} } @article {rebesco2014boundary, title = {Boundary condition of grounding lines prior to collapse, Larsen-B Ice Shelf, Antarctica}, journal = {Science}, volume = {345}, number = {6202}, year = {2014}, pages = {1354{\textendash}1358}, publisher = {American Association for the Advancement of Science}, author = {Rebesco, M and Domack, E and Zgur, F and Lavoie, C and Leventer, A and Brachfeld, S and Willmott, V and Halverson, G and Truffer, M and Scambos, T and Pettit, Erin C} } @inbook {352, title = {Glacier Surges}, booktitle = {Snow and Ice-Related Hazards, Risks, and Disasters}, year = {2014}, abstract = {{\textcopyright} 2015 Elsevier Inc. All rights reserved.Surge-type glaciers periodically undergo large flow acceleration after extended quiescent phases of slow movement, usually accompanied by terminus advance. Such glaciers are relatively rare but occur in many of the world{\textquoteright}s glacierized areas. High water pressures and extreme basal sliding are obvious characteristics but key questions concerning this, usually spectacular phenomenon, remain open. Why are glaciers in some regions surge-type but not in others, what sort of "memory" lets glaciers surge again and again, what is the influence of climate, geology, and topography? Besides their scientific interest, glacier surges can also be a threat to humans, especially in connection with rapidly forming lakes and their sudden outbursts. Cases of hazard- and disaster-related glacier surges are described from the Pamirs, the Andes, the Italian Alps, and Alaska.}, keywords = {Flow instabilities, Ice dammed lakes, Outburst floods, Pipeline safety, River blocking, surge-type glaciers}, isbn = {9780123964731}, doi = {10.1016/B978-0-12-394849-6.00013-5}, author = {Harrison, W.D. and Osipova, G.B. and Nosenko, G.A. and Espizua, L. and K{\"a}{\"a}b, A. and L Fischer and Huggel, C. and Craw Burns, P.A. and Truffer, M. and Lai, A.W.} } @article {353, title = {Ice Thickness Measurements on the Harding Icefield , Kenai Peninsula , Alaska}, year = {2014}, author = {Truffer, Martin} } @article {355, title = {Quantifying velocity response to ocean tides and calving near the terminus of Jakobshavn Isbr{\ae}, Greenland}, journal = {Journal of Glaciology}, volume = {60}, year = {2014}, pages = {609{\textendash}621}, keywords = {calving, glacier fluctuations, ice, ocean interactions}, issn = {00221430}, doi = {10.3189/2014JoG13J130}, url = {http://www.igsoc.org/journal/60/222/t13J130.html}, author = {Podrasky, David and Truffer, Martin and L{\"u}thi, Martin and Fahnestock, Mark} } @article {354, title = {Surface Drifters Track the Fate of Greenland Ice Sheet Meltwater}, journal = {Eos Trans. AGU}, volume = {95}, year = {2014}, pages = {237{\textendash}239}, doi = {10.1002/2014EO260002}, author = {Hauri, C. and Truffer, M. and Winsor, P. and Lennert, K.} } @article {2013/08/01, title = {Challenges to Understanding the Dynamic Response of Greenland{\textquoteright}s Marine Terminating Glaciers to Oceanic and Atmospheric Forcing}, journal = {Bulletin of the American Meteorological Society}, volume = {94}, year = {2013}, month = {2013/08/01}, pages = {1131 - 1144}, doi = {10.1175/BAMS-D-12-00100.1}, url = {http://dx.doi.org/10.1175/BAMS-D-12-00100.1}, author = {Straneo, Fiammetta and Heimbach, Patrick and Sergienko, Olga and Hamilton, Gordon and Catania, Ginny and Griffies, Stephen and Hallberg, Robert and Jenkins, Adrian and Joughin, Ian and Motyka, Roman and Pfeffer, W. Tad and Stephen F. Price and Eric Rignot and Scambos, Ted and Martin Truffer and Vieli, Andreas} } @article {11/2013, title = {Changing basal conditions during the speed-up of Jakobshavn Isbr{\ae}, Greenland}, journal = {The Cryosphere}, volume = {7}, year = {2013}, month = {11/2013}, pages = {1679{\textendash}1692}, author = {Habermann, M and Martin Truffer and Maxwell, D} } @article {sep, title = {Channelized ice melting in the ocean boundary layer beneath Pine Island Glacier, Antarctica.}, journal = {Science (New York, N.Y.)}, volume = {341}, year = {2013}, month = {sep}, pages = {1236{\textendash}9}, abstract = {Ice shelves play a key role in the mass balance of the Antarctic ice sheets by buttressing their seaward-flowing outlet glaciers; however, they are exposed to the underlying ocean and may weaken if ocean thermal forcing increases. An expedition to the ice shelf of the remote Pine Island Glacier, a major outlet of the West Antarctic Ice Sheet that has rapidly thinned and accelerated in recent decades, has been completed. Observations from geophysical surveys and long-term oceanographic instruments deployed down bore holes into the ocean cavity reveal a buoyancy-driven boundary layer within a basal channel that melts the channel apex by 0.06 meter per day, with near-zero melt rates along the flanks of the channel. A complex pattern of such channels is visible throughout the Pine Island Glacier shelf.}, keywords = {Antarctic Regions, Freezing, Ice Cover, Oceans and Seas}, issn = {1095-9203}, doi = {10.1126/science.1239373}, url = {http://www.ncbi.nlm.nih.gov/pubmed/24031016}, author = {Stanton, T P and Shaw, W J and Truffer, M. and Corr, H F J and Peters, L E and Riverman, K L and Bindschadler, R and Holland, D M and Anandakrishnan, S} } @article {SeariseAntarctica2013, title = {{Insights into spatial sensitivities of ice mass response to environmental change from the SeaRISE ice sheet modeling project I: Antarctica}}, journal = {J. Geophys. Res.}, volume = {118}, number = {2}, year = {2013}, pages = {1002{\textendash}1024}, issn = {21699003}, doi = {10.1002/jgrf.20081}, url = {http://doi.wiley.com/10.1002/jgrf.20081}, author = {Nowicki, Sophie and Robert A. Bindschadler and Abe-Ouchi, Ayako and Andy Aschwanden and E. Bueler and Choi, Hyeungu and Fastook, Jim and Granzow, Glen and Greve, Ralf and Gutowski, Gail and Herzfeld, Ute and Jackson, Charles and Jesse V Johnson and Constantine Khroulev and Larour, Eric and Anders Levermann and Lipscomb, William H. and Maria A. Martin and Morlighem, Mathieu and Parizek, Byron R. and David Pollard and Stephen F. Price and Ren, Diandong and Eric Rignot and Fuyuki Saito and Tatsuru Sato and Seddik, Hakime and Seroussi, Helene and Takahashi, Kunio and Walker, Ryan and Wang, Wei Li} } @article {SeariseGreenland2013, title = {{Insights into spatial sensitivities of ice mass response to environmental change from the SeaRISE ice sheet modeling project II: Greenland}}, journal = {J. Geophys. Res.}, volume = {118}, number = {2}, year = {2013}, month = {jun}, pages = {1025{\textendash}1044}, issn = {21699003}, doi = {10.1002/jgrf.20076}, url = {http://doi.wiley.com/10.1002/jgrf.20076}, author = {Nowicki, Sophie and Robert A. Bindschadler and Abe-Ouchi, Ayako and Andy Aschwanden and E. Bueler and Choi, Hyeungu and Fastook, Jim and Granzow, Glen and Greve, Ralf and Gutowski, Gail and Herzfeld, Ute and Jackson, Charles and Jesse V Johnson and Constantine Khroulev and Larour, Eric and Anders Levermann and Lipscomb, William H. and Maria A. Martin and Morlighem, Mathieu and Parizek, Byron R. and David Pollard and Stephen F. Price and Ren, Diandong and Eric Rignot and Fuyuki Saito and Tatsuru Sato and Seddik, Hakime and Seroussi, Helene and Takahashi, Kunio and Walker, Ryan and Wang, Wei Li} } @article {165, title = {The propagation of a surge front on Bering Glacier, Alaska, 2001\&$\#$8211;2011}, journal = {Annals of Glaciology}, volume = {54}, year = {2013}, pages = {221-228}, abstract = {Bering Glacier, Alaska, USA, has a \&$\#$8764;20 year surge cycle, with its most recent surge reaching the terminus in 2011. To study this most recent activity a time series of ice velocity maps was produced by applying optical feature-tracking methods to Landsat-7 ETM+ imagery spanning 2001\&$\#$8211;11. The velocity maps show a yearly increase in ice surface velocity associated with the down-glacier movement of a surge front. In 2008/09 the maximum ice surface velocity was 1.5 {\textpm} 0.017 km a\&$\#$8211;1 in the mid-ablation zone, which decreased to 1.2 {\textpm} 0.015 km a\&$\#$8211;1 in 2009/10 in the lower ablation zone, and then increased to nearly 4.4 {\textpm} 0.03 km a\&$\#$8211;1 in summer 2011 when the surge front reached the glacier terminus. The surge front propagated down-glacier as a kinematic wave at an average rate of 4.4 {\textpm} 2.0 km a\&$\#$8211;1 between September 2002 and April 2009, then accelerated to 13.9 {\textpm} 2.0 km a\&$\#$8211;1 as it entered the piedmont lobe between April 2009 and September 2010. The wave seems to have initiated near the confluence of Bering Glacier and Bagley Ice Valley as early as 2001, and the surge was triggered in 2008 further down-glacier in the mid-ablation zone after the wave passed an ice reservoir area.}, doi = {doi:10.3189/2013AoG63A341}, url = {http://www.ingentaconnect.com/content/igsoc/agl/2013/00000054/00000063/art00024}, author = {Turrin, James and Richard R. Forster and Chris F. Larsen and Sauber, Jeanne} } @article {152, title = {Rapid Submarine Melting Driven by Subglacial Discharge, LeConte Glacier, Alaska}, journal = {Geophysical Research Letters}, volume = {40}, year = {2013}, abstract = {We show that subglacial freshwater discharge is the principal process driving high rates of submarine melting at tidewater glaciers. This buoyant discharge draws in warm seawater, entraining it in a turbulent upwelling flow along the submarine face that melts glacier ice. To capture the effects of subglacial discharge on submarine melting, we conducted 4 days of hydrographic transects during late summer 2012 at LeConte Glacier, Alaska. A major rainstorm allowed us to document the influence of large changes in subglacial discharge. We found strong submarine melt fluxes that increased from 9.1 {\textpm} 1.0 to 16.8 {\textpm} 1.3 m d-1 (ice face equivalent frontal ablation) as a result of the rainstorm. With projected continued global warming and increased glacial runoff, our results highlight the direct impact that increases in subglacial discharge will have on tidewater outlet systems. These effects must be considered when modeling glacier response to future warming and increased runoff.}, keywords = {frontal ablation, submarine melting, tidewater glaciers}, issn = {1944-8007}, doi = {10.1002/grl.51011}, url = {http://dx.doi.org/10.1002/grl.51011}, author = {Roman J. Motyka and Dryer, W. P. and Jason M Amundson and Martin Truffer and Mark Fahnestock} } @article {357, title = {Rapid thinning of lake-calving Yakutat Glacier and the collapse of the Yakutat Icefield, southeast Alaska, USA}, journal = {J. Glaciol.}, volume = {59}, year = {2013}, pages = {149{\textendash}161}, issn = {00221430}, doi = {10.3189/2013J0G12J081}, url = {http://www.igsoc.org/journal/59/213/t12J081.html}, author = {Tr{\"u}ssel, Barbara L. and Motyka, Roman J. and Truffer, M. and Larsen, C. F.} } @article {153, title = {On the seasonal freshwater stratification in the proximity of fast-flowing tidewater outlet glaciers in a sub-Arctic sill fjord}, journal = {Journal of Geophysical Research: Oceans}, volume = {118}, year = {2013}, pages = {1382{\textendash}1395}, abstract = {The Greenland Ice Sheet releases large amounts of freshwater into the fjords around Greenland and many fjords are in direct contact with the ice sheet through tidewater outlet glaciers. Here we present the first seasonal hydrographic observations from the inner part of a sub-Arctic fjord, relatively close to and within 4{\textendash}50 km of a fast-flowing tidewater outlet glacier. This region is characterized by a dense glacial and sea ice cover. Freshwater from runoff, subglacial freshwater (SgFW) discharge, glacial, and sea ice melt are observed above 50{\textendash}90 m depth. During summer, SgFW and subsurface glacial melt mixed with ambient water are observed as a layered structure in the temperature profiles below the low-saline summer surface layer (<7 m). During winter, the upper water column is characterized by stepwise halo- and thermoclines formed by mixing between deeper layers and the surface layer influenced by ice melt. The warm (T > 1{\textdegree}C) intermediate water mass is a significant subsurface heat source for ice melt. We analyze the temperature and salinity profiles observed in late summer with a thermodynamic mixing model and determine the total freshwater content in the layer below the summer surface layer to be between 5\% and 11\%. The total freshwater contribution in this layer from melted glacial ice was estimated to be 1{\textendash}2\%, while the corresponding SgFW was estimated to be 3{\textendash}10\%. The winter measurements in the subsurface halocline layer showed a total freshwater content of about 1\% and no significant contribution from SgFW.}, keywords = {fjord, freshwater sources and their distribution, Greenland Ice Sheet, subglacial freshwater fraction model, subsurface heat sources for glacial ice melt, tidewater outlet glaciers}, issn = {2169-9291}, doi = {10.1002/jgrc.20134}, url = {http://dx.doi.org/10.1002/jgrc.20134}, author = {Mortensen, J. and Bendtsen, J. and Roman J. Motyka and Lennert, K. and Martin Truffer and Mark Fahnestock and Rysgaard, S.} } @article {mar, title = {Analysis of low-frequency seismic signals generated during a multiple-iceberg calving event at Jakobshavn Isbr{\ae}, Greenland}, journal = {Journal of Geophysical Research}, volume = {117}, year = {2012}, month = {mar}, pages = {1{\textendash}11}, keywords = {calving, glacier, iceberg, seismology}, issn = {0148-0227}, doi = {10.1029/2011JF002132}, url = {http://www.agu.org/pubs/crossref/2012/2011JF002132.shtml}, author = {Walter, F. and Amundson, J. M. and O{\textquoteright}Neel, S. and Truffer, M. and Fahnestock, M.A. and Fricker, H. A.} } @article {zagorodnov2012borehole, title = {Borehole temperatures reveal details of 20th century warming at Bruce Plateau, Antarctic Peninsula}, journal = {The Cryosphere}, volume = {6}, number = {3}, year = {2012}, pages = {675{\textendash}686}, publisher = {Copernicus GmbH}, author = {Zagorodnov, V and Nagornov, O and Scambos, TA and Muto, A and Mosley-Thompson, E and Erin C Pettit and Tyuflin, S} } @article {360, title = {Observing calving-generated ocean waves with coastal broadband seismometers, Jakobshavn Isbr{\ae}, Greenland}, journal = {Annals Of Glaciology}, volume = {53}, year = {2012}, pages = {79{\textendash}84}, doi = {10.3189/2012/AoG60A200}, author = {Amundson, J. M. and Clinton, John F and Fahnestock, M.A. and Truffer, M. and Motyka, Roman J. and L{\"u}thi, Martin P.} } @article {dec, title = {Outlet glacier response to forcing over hourly to interannual timescales, Jakobshavn Isbr{\ae}, Greenland}, journal = {J. Glaciol.}, volume = {58}, year = {2012}, month = {dec}, pages = {1212{\textendash}1226}, issn = {00221430}, doi = {10.3189/2012JoG12J065}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0022-1430{\&}volume=58{\&}issue=212{\&}spage=1212}, author = {Podrasky, David and Truffer, Martin and Fahnestock, Mark and Amundson, Jason M. and Cassotto, Ryan and Joughin, Ian} } @article {123, title = {Outlet glacier response to forcing over hourly to interannual timescales, Jakobshavn Isbr{\ae}, Greenland}, journal = {Journal of Glaciology}, volume = {58}, year = {2012}, pages = {1212}, doi = {10.3189/2012JoG12J065}, author = {Podrasky, David and Martin Truffer and Mark Fahnestock and Jason M Amundson and Cassotto, Ryan and Ian Joughin} } @article {77, title = {Reconstruction of basal properties in ice sheets using iterative inverse methods}, journal = {Journal of Glaciology}, volume = {58}, year = {2012}, pages = {795{\textendash}807}, author = {Habermann, M. and Maxwell, D. and Martin Truffer} } @article {Joughin2012, title = {{Seasonal to decadal scale variations in the surface velocity of Jakobshavn Isbrae, Greenland: Observation and model-based analysis}}, journal = {J. Geophys. Res.}, volume = {117}, number = {F2}, year = {2012}, month = {may}, pages = {1{\textendash}20}, keywords = {glacier, glaciology, ice stream}, issn = {0148-0227}, doi = {10.1029/2011JF002110}, url = {http://www.agu.org/pubs/crossref/2012/2011JF002110.shtml}, author = {Joughin, Ian and Smith, B. E. and Howat, I. M. and Floricioiu, Dana and Alley, Richard B. and Truffer, M. and Fahnestock, M.A.} } @article {76, title = {{Using surface velocities to calculate ice thickness and bed topography: a case study at Columbia Glacier, Alaska, USA}}, journal = {Journal of Glaciology}, volume = {58}, year = {2012}, pages = {1151-1164}, doi = {10.3189/2012JoG11J249}, author = {R ~W McNabb and Regine Hock and Shad O'Neel and L ~A Rasmussen and Ahn, Y. and M Braun and H Conway and Herreid, S. and Ian Joughin and W. Tad Pfeffer and B ~E Smith and Martin Truffer} } @article {pettit2011crossover, title = {The crossover stress, anisotropy and the ice flow law at Siple Dome, West Antarctica}, journal = {Journal of Glaciology}, volume = {57}, number = {201}, year = {2011}, pages = {39{\textendash}52}, publisher = {International Glaciological Society}, author = {Erin C Pettit and Waddington, Edwin D and Harrison, William D and Thorsteinsson, Throstur and Elsberg, Daniel and Morack, John and Zumberge, Mark A} } @article {69, title = {From ice-shelf tributary to tidewater glacier: continued rapid recession, acceleration and thinning of Rohss Glacier following the 1995 collapse of the Prince Gustav Ice Shelf, Antarctic Peninsula}, journal = {Journal of Glaciology}, volume = {57}, year = {2011}, pages = {397{\textendash}406}, doi = {10.3189/002214311796905578}, url = {http://openurl.ingenta.com/content/xref?genre=article\&issn=0022-1430\&volume=57\&issue=203\&spage=397}, author = {Glasser, NF and Scambos, TA and Bohlander, J. and Martin Truffer and Erin C Pettit and Davies, BJ} } @article {60, title = {Submarine melting of the 1985 Jakobshavn Isbr{\ae} floating tongue and the triggering of the current retreat}, journal = {Journal of Geophysical Research}, volume = {116}, year = {2011}, pages = {F01007}, doi = {10.1029/2009JF001632}, author = {Roman J. Motyka and Martin Truffer and Mark Fahnestock and Mortensen, J. and Rysgaard, S. and I M Howat} } @article {44, title = {Glacier microseismicity}, journal = {Geology}, volume = {38}, year = {2010}, pages = {319-322}, abstract = {We present a framework for interpreting small glacier seismic events based on data collected near the center of Bering Glacier, Alaska, in spring 2007. We find extremely high microseismicity rates (as many as tens of events per minute) occurring largely within a few kilometers of the receivers. A high-frequency class of seismicity is distinguished by dominant frequencies of 20{\textendash}35 Hz and impulsive arrivals. A low-frequency class has dominant frequencies of 6{\textendash}15 Hz, emergent onsets, and longer, more monotonic codas. A bimodal distribution of 160,000 seismic events over two months demonstrates that the classes represent two distinct populations. This is further supported by the presence of hybrid waveforms that contain elements of both event types. The high-low-hybrid paradigm is well established in volcano seismology and is demonstrated by a comparison to earthquakes from Augustine Volcano. We build on these parallels to suggest that fluid-induced resonance is likely responsible for the low-frequency glacier events and that the hybrid glacier events may be caused by the rush of water into newly opening pathways.}, doi = {10.1130/G30606.1}, url = {http://geology.gsapubs.org/content/38/4/319.abstract}, author = {West, M. and Chris F. Larsen and Martin Truffer and Shad O'Neel and LeBlanc, Laura} } @article {56, title = {Ice m{\'e}lange dynamics and implications for terminus stability, Jakobshavn Isbr{\ae}, Greenland}, journal = {Journal of Geophysical Research}, volume = {115}, year = {2010}, pages = {F01005}, doi = {10.1029/2009JF001405}, author = {Jason M Amundson and Mark Fahnestock and Martin Truffer and Brown, J. and M P L{\"u}thi and Roman J. Motyka} } @article {54, title = {Results from the Ice-Sheet Model Intercomparison ProjectHeinrich Event INtercOmparison (ISMIP HEINO)}, journal = {Journal of Glaciology}, volume = {56}, year = {2010}, pages = {371-383}, abstract = {Results from the Heinrich Event INtercOmparison (HEINO) topic of the Ice-Sheet Model Intercomparison Project (ISMIP) are presented. ISMIP HEINO was designed to explore internal large-scale ice-sheet instabilities in different contemporary ice-sheet models. These instabilities are of interest because they are a possible cause of Heinrich events. A simplified geometry experiment reproduces the main characteristics of the Laurentide ice sheet, including the sedimented region over Hudson Bay and Hudson Strait. The model experiments include a standard run plus seven variations. Nine dynamic/thermodynamic ice-sheet models were investigated; one of these models contains a combination of the shallow-shelf (SSA) and shallow-ice approximation (SIA), while the remaining eight models are of SIA type only. Seven models, including the SIA-SSA model, exhibit oscillatory surges with a period of \&$\#$8764;1000 years for a broad range of parameters, while two models remain in a permanent state of streaming for most parameter settings. In a number of models, the oscillations disappear for high surface temperatures, strong snowfall and small sediment sliding parameters. In turn, low surface temperatures and low snowfall are favourable for the ice-surge cycles. We conclude that further improvement of ice-sheet models is crucial for adequate, robust simulations of cyclic large-scale instabilities.}, doi = {doi:10.3189/002214310792447789}, url = {http://www.ingentaconnect.com/content/igsoc/jog/2010/00000056/00000197/art00001}, author = {Calov, Reinhard and Greve, Ralf and Abe-Ouchi, Ayako and E. Bueler and Huybrechts, Philippe and Jesse V Johnson and Frank Pattyn and David Pollard and Ritz, Catherine and Fuyuki Saito and Tarasov, Lev} } @article {58, title = {A unifying framework for iceberg-calving models}, journal = {Journal of Glaciology}, volume = {56}, year = {2010}, pages = {822{\textendash}830}, url = {http://openurl.ingenta.com/content/xref?genre=article\&issn=0022-1430\&volume=56\&issue=199\&spage=822}, author = {Jason M Amundson and Martin Truffer} } @article {49, title = {Volume change of Jakobshavn Isbrae, West Greenland:: 198519972007}, journal = {Journal of Glaciology}, volume = {56}, year = {2010}, pages = {635{\textendash}646}, url = {http://openurl.ingenta.com/content/xref?genre=article\&issn=0022-1430\&volume=56\&issue=198\&spage=635}, author = {Roman J. Motyka and Mark Fahnestock and Martin Truffer} } @article {35, title = {Calving icebergs indicate a thick layer of temperate ice at the base of Jakobshavn Isbr{\ae}, Greenland}, journal = {Journal of Glaciology}, volume = {55}, year = {2009}, pages = {563{\textendash}566}, url = {http://openurl.ingenta.com/content/xref?genre=article\&issn=0022-1430\&volume=55\&issue=191\&spage=563}, author = {M P L{\"u}thi and Mark Fahnestock and Martin Truffer} } @article {39, title = {Iterative methods for solving a nonlinear boundary inverse problem in glaciology}, journal = {Journal of Inverse and Ill-posed Problems}, volume = {17}, year = {2009}, pages = {239{\textendash}258}, url = {http://www.reference-global.com/doi/abs/10.1515/JIIP.2}, author = {Avdonin, S. and Kozlov, V. and Maxwell, D. and Martin Truffer} } @article {40, title = {A method to estimate the ice volume and ice-thickness distribution of alpine glaciers}, journal = {Journal of Glaciology}, volume = {55}, year = {2009}, pages = {422{\textendash}430}, url = {http://openurl.ingenta.com/content/xref?genre=article\&issn=0022-1430\&volume=55\&issue=191\&spage=422}, author = {Farinotti, D. and Huss, M. and Bauder, A. and Funk, M. and Martin Truffer} } @article {33, title = {Terminus dynamics at an advancing glacier: Taku Glacier, Alaska}, journal = {Journal of Glaciology}, volume = {55}, year = {2009}, pages = {1052{\textendash}1060}, url = {http://openurl.ingenta.com/content/xref?genre=article\&issn=0022-1430\&volume=55\&issue=194\&spage=1052}, author = {Martin Truffer and Roman J. Motyka and Hekkers, M. and I M Howat and King, M.A.} } @article {28, title = {Continued evolution of Jakobshavn Isbrae following its rapid speedup}, journal = {J. geophys. Res}, volume = {113}, year = {2008}, pages = {F04006}, url = {http://www.agu.org/pubs/crossref/2008/2008JF001023.shtml}, author = {Ian Joughin and I M Howat and Mark Fahnestock and B ~E Smith and Krabill, W. and Alley, R.B. and Stern, H. and Martin Truffer} } @article {31, title = {Correspondence: Another surge of Variegated Glacier, Alaska, USA, 2003/04}, journal = {Journal of Glaciology}, volume = {54}, year = {2008}, pages = {192-200}, doi = {doi:10.3189/002214308784409134}, url = {http://www.ingentaconnect.com/content/igsoc/jog/2008/00000054/00000184/art00019}, author = {Harrison, W. and Roman J. Motyka and Martin Truffer} } @article {32, title = {Glacier, fjord, and seismic response to recent large calving events, Jakobshavn Isbr{\ae}, Greenland}, journal = {Geophysical Research Letters}, volume = {35}, year = {2008}, pages = {L22501}, url = {http://www.agu.org/pubs/crossref/2008/2008GL035281.shtml}, author = {Jason M Amundson and Martin Truffer and M P L{\"u}thi and Mark Fahnestock and West, M. and Roman J. Motyka} } @article {17, title = {Glacier Recession on Heard Island, Southern Indian Ocean}, journal = {Arctic, Antarctic, and Alpine Research}, volume = {40}, year = {2008}, pages = {199{\textendash}214}, url = {http://www.bioone.org/doi/abs/10.1657/1523-0430(06-084)\%5BTHOST\%5D2.0.CO;2}, author = {Thost, D.E. and Martin Truffer} } @article {29, title = {Ice-front variation and tidewater behavior on Helheim and Kangerdlugssuaq Glaciers, Greenland}, journal = {Journal of Geophysical Research}, volume = {113}, year = {2008}, pages = {F01004}, url = {http://www.agu.org/pubs/crossref/2008/2007JF000837.shtml}, author = {Ian Joughin and I M Howat and Alley, R.B. and Ekstrom, G. and Mark Fahnestock and Moon, T. and Nettles, M. and Martin Truffer and Tsai, V.C.} } @article {Joughin2008a, title = {{Ice-front variation and tidewater behavior on Helheim and Kangerdlugssuaq Glaciers, Greenland}}, journal = {Journal of Geophysical Research: Earth Surface}, volume = {113}, number = {1}, year = {2008}, month = {jan}, pages = {1{\textendash}11}, abstract = {We used satellite images to examine the calving behavior ofHelheim and Kangerdlugssuaq Glaciers, Greenland, from 2001 to 2006, a period in which they retreated and speed up. These data show that many large iceberge-calving episodes coincided with teleseismically detected glacial erthquakes, suggesting that calving-related processes are the source of seismicity. For each of several events for which we hace observations, the ice front calved back to a large, pre-existing rift. These refits form where the ice has thinned to near flotation as the ice front retreats down back side of a bathymetric high, which agrees well with earlier theoretical predictions. In adition to recent retreat in a period of high temperature, analysis of several images shows that Helhaim retreated in the 20th Century during a warmer period and then re-adcanced during a subsequent cooler period. This apparent sensitivity to waming suggests that higher temperatures may promote an initial retread off a bathymetric high that is then sustained by tidewater dynamics as the ice front retreats into depper water. The cycle of frontal advance and retreat in less than a century indicates that tidewater glaciers in Greenland can advance rapidly. Greenland{\textquoteright}s larger resorvoir of inland ice and conditions that favor the formation of ice shelves likely contribute to the rapid rates of advance.}, isbn = {0148-0227}, issn = {21699011}, doi = {10.1029/2007JF000837}, url = {http://www.agu.org/pubs/crossref/2008/2007JF000837.shtml}, author = {Joughin, Ian and Howat, Ian and Alley, Richard B. and Ekstrom, Goran and Fahnestock, Mark and Moon, Twila and Nettles, Meredith and Truffer, Martin and Tsai, Victor C.} } @article {24, title = {An iterative scheme for determining glacier velocities and stresses}, journal = {Journal of Glaciology}, volume = {54}, year = {2008}, pages = {888{\textendash}898}, url = {http://openurl.ingenta.com/content/xref?genre=article\&issn=0022-1430\&volume=54\&issue=188\&spage=888}, author = {Maxwell, D. and Martin Truffer and Avdonin, S. and Stuefer, M.} } @article {20, title = {Seasonal fluctuations in the advance of a tidewater glacier and potential causes: Hubbard Glacier, Alaska, USA}, journal = {Journal of Glaciology}, volume = {54}, year = {2008}, pages = {401{\textendash}411}, url = {http://openurl.ingenta.com/content/xref?genre=article\&issn=0022-1430\&volume=54\&issue=186\&spage=401}, author = {Ritchie, J.B. and C S Lingle and Roman J. Motyka and Martin Truffer} } @article {27, title = {Seasonality of snow accumulation at Mount Wrangell, Alaska, USA}, journal = {Journal of Glaciology}, volume = {54}, year = {2008}, pages = {273{\textendash}278}, url = {http://www.ingentaconnect.com/content/igsoc/jog/2008/00000054/00000185/art00008}, author = {Kanamori, S. and Benson, C.S. and Martin Truffer and Matoba, S. and Solie, D.J. and Shiraiwa, T.} } @article {15, title = {Flotation and retreat of a lake-calving terminus, Mendenhall Glacier, southeast Alaska, USA}, journal = {Journal of Glaciology}, volume = {53}, year = {2007}, pages = {211{\textendash}224}, author = {Boyce, E.S. and Roman J. Motyka and Martin Truffer} } @article {16, title = {Glaciervolcano interactions in the North Crater of Mt Wrangell, Alaska}, journal = {Annals of Glaciology}, volume = {45}, year = {2007}, pages = {48{\textendash}57}, author = {Benson, C.S. and Roman J. Motyka and McNUTT, S. and M P L{\"u}thi and Martin Truffer} } @article {5, title = {Hubbard Glacier, Alaska: 2002 closure and outburst of Russell Fjord and postflood conditions at Gilbert Point}, journal = {Journal of geophysical research}, volume = {112}, year = {2007}, pages = {F02004}, author = {Roman J. Motyka and Martin Truffer} } @article {tremblay2007ocean, title = {Ocean acoustic effects of explosions on land: Evaluation of Cook Inlet beluga whale habitability}, journal = {The Journal of the Acoustical Society of America}, volume = {122}, number = {5}, year = {2007}, pages = {3002{\textendash}3002}, publisher = {Acoustical Society of America}, author = {Tremblay, Sara K and Anderson, Thomas S and Pettit, Erin C and Scheifele, Peter M and Potty, Gopu R and Miller, James H} } @article {3, title = {Rethinking ice sheet time scales}, journal = {Science}, volume = {315}, year = {2007}, pages = {1508{\textendash}1510}, doi = {10.1126/science.11404}, author = {Martin Truffer and Mark Fahnestock} } @article {pettit2007role, title = {The role of crystal fabric in flow near an ice divide}, journal = {Journal of Glaciology}, volume = {53}, number = {181}, year = {2007}, pages = {277{\textendash}288}, publisher = {International Glaciological Society}, author = {Erin C Pettit and Thorsteinsson, Throstur and Jacobson, H Paul and Waddington, Edwin D} } @article {364, title = {Episodic reactivation of large-scale push moraines in front of the advancing Taku Glacier, Alaska}, journal = {J. Geophys. Res.}, volume = {111}, year = {2006}, pages = {{\textendash}01009}, issn = {0148-0227}, doi = {10.1029/2005JF000385}, url = {http://www.agu.org/pubs/crossref/2006/2005JF000385.shtml}, author = {Kuriger, Elsbeth Maria and Truffer, M. and Motyka, Roman J. and Bucki, Adam K.} } @article {mar, title = {In situ measurements of till deformation and water pressure}, journal = {J. Glaciol.}, volume = {52}, year = {2006}, month = {mar}, pages = {175{\textendash}182}, issn = {00221430}, doi = {10.3189/172756506781828700}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0022-1430{\&}volume=52{\&}issue=177{\&}spage=175}, author = {Truffer, M. and Harrison, W.D.} } @article {dec, title = {Rapid erosion of soft sediments by tidewater glacier advance: Taku Glacier, Alaska, USA}, journal = {Geophys. Res. Lett.}, volume = {33}, year = {2006}, month = {dec}, pages = {1{\textendash}5}, issn = {0094-8276}, doi = {10.1029/2006GL028467}, url = {http://www.agu.org/pubs/crossref/2006/2006GL028467.shtml}, author = {Motyka, Roman J. and Truffer, M. and Kuriger, Elsbeth Maria and Bucki, Adam K.} } @article {362, title = {Time-dependent basal stress conditions beneath Black Rapids Glacier, Alaska, USA, inferred from measurements of ice deformation and surface motion}, journal = {J. Glaciol.}, volume = {52}, year = {2006}, pages = {347{\textendash}357}, issn = {00221430}, doi = {10.3189/172756506781828593}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0022-1430{\&}volume=52{\&}issue=178{\&}spage=347}, author = {Amundson, J. M. and Truffer, M. and L{\"u}thi, Martin P.} } @article {conway2005candidate, title = {Candidate drill site near the Ross-Amundsen ice divide, West Antarctica}, journal = {DRAFT, Mar}, year = {2005}, author = {Conway, H and Neumann, TA and Stephen F. Price and Waddington, ED and Morse, D and Taylor, K and Mayewski, PA and Dixon, D and Erin C Pettit and Steig, EJ} } @article {conway2005proposed, title = {Proposed drill site near the Ross{\textendash}Amundsen ice divide, West Antarctica}, journal = {White Paper for the US Ice Core Working Group}, year = {2005}, author = {Conway, H and Neumann, TA and Stephen F. Price and Waddington, ED and Morse, D and Taylor, K and Mayewski, PA and Dixon, D and Erin C Pettit and Steig, EJ} } @article {sep, title = {Record negative glacier balances and low velocities during the 2004 heatwave in Alaska, USA: implications for the interpretation of observations by Zwally and others in Greenland}, journal = {Journal of Glaciology}, volume = {51}, year = {2005}, month = {sep}, pages = {663{\textendash}664}, issn = {0022-1430}, doi = {10.3189/172756505781829016}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0022-1430{\&}volume=51{\&}issue=175{\&}spage=663 https://www.cambridge.org/core/product/identifier/S002214300021085X/type/journal{\_}article}, author = {Truffer, Martin and Harrison, W.D. and March, R.S.} } @article {mar, title = {The basal speed of valley glaciers: an inverse approach}, journal = {J. Glaciol.}, volume = {50}, year = {2004}, month = {mar}, pages = {236{\textendash}242}, issn = {00221430}, doi = {10.3189/172756504781830088}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0022-1430{\&}volume=50{\&}issue=169{\&}spage=236}, author = {Truffer, M.} } @article {366, title = {Probing the till beneath Black Rapids Glacier, Alaska, USA}, journal = {J. Glaciol.}, volume = {50}, year = {2004}, pages = {608{\textendash}614}, issn = {00221430}, doi = {10.3189/172756504781829693}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0022-1430{\&}volume=50{\&}issue=171{\&}spage=608}, author = {Harrison, W.D. and Truffer, M. and Echelmeyer, K. A. and Pomraning, D. A. and Abnett, K. A. and Ruhkick, R. H.} } @article {370, title = {Of isbr{\ae} and ice streams}, journal = {Ann. Glaciol.}, volume = {36}, year = {2003}, pages = {66{\textendash}72}, issn = {02603055}, doi = {10.3189/172756403781816347}, author = {Truffer, M. and Echelmeyer, K. A.} } @article {jan, title = {A surface motion survey of Black Rapids Glacier, Alaska, U.S.A.}, journal = {Ann. Glaciol.}, volume = {36}, year = {2003}, month = {jan}, pages = {29{\textendash}36}, issn = {02603055}, doi = {10.3189/172756403781816095}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0260-3055{\&}volume=36{\&}issue=1{\&}spage=29}, author = {Fatland, Dennis R. and Lingle, Craig S. and Truffer, M.} } @article {369, title = {Mechanisms of fast flow in Jakobshavns Isbr{\ae}, Greenland, Part III: Measurements of ice deformation, temperature and cross-borehole conductivity in boreholes to the bedrock}, journal = {J. Glaciol.}, volume = {48}, year = {2002}, pages = {369{\textendash}385}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0022-1430{\&}volume=48{\&}issue=162{\&}spage=369}, author = {L{\"u}thi, Martin P. and Funk, M. and Iken, A. and Truffer, M. and Gogineni, S.} } @article {feb, title = {Implications of till deformation on glacier dynamics}, journal = {J. Glaciol.}, volume = {47}, year = {2001}, month = {feb}, pages = {123{\textendash}134}, issn = {00221430}, doi = {10.3189/172756501781832449}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0022-1430{\&}volume=47{\&}issue=156{\&}spage=123}, author = {Truffer, M. and Echelmeyer, K. A. and Harrison, W.D.} } @article {sep, title = {Glacier motion dominated by processes deep in underlying till}, journal = {J. Glaciol.}, volume = {46}, year = {2000}, month = {sep}, pages = {213{\textendash}221}, issn = {00221430}, doi = {10.3189/172756500781832909}, url = {http://openurl.ingenta.com/content/xref?genre=article{\&}issn=0022-1430{\&}volume=46{\&}issue=153{\&}spage=213}, author = {Truffer, M. and Harrison, W.D. and Echelmeyer, K. A.} } @article {373, title = {Subglacial drilling at Black Rapids Glacier, Alaska, U.S.A : drilling method and sample descriptions}, journal = {J. Glaciol.}, volume = {45}, year = {1999}, pages = {495{\textendash}505}, author = {Truffer, M. and Motyka, Roman J. and Harrison, W.D. and Echelmeyer, K. A. and Fisk, B. and Tulaczyk, S.} } @article {375, title = {The sliding velocity over a sinusoidal bed at high water pressure}, journal = {Journal of Glaciology}, volume = {44}, year = {1998}, pages = {379{\textendash}382}, doi = {10.3189/S0022143000002707}, author = {Truffer, Martin and Iken, Almut} } @article {374, title = {The relationship between subglacial water pressure and velocity of Findelengletscher, Switzerland, during its advance and retreat} volume = {43}, journal = {Journal of Glaciology}, year = {1997}, pages = {328{\textendash}338}, abstract = {Findelengletscher, Switzerland, advanced about 250 m between 1979$\backslash$nand 1985, and retreated thereafter. Subglacial water pressure, surface$\backslash$nvelocity and surface strain rate were determined at several sites.$\backslash$nThe measurements were made early in the melt seasons of 1980, 1982,$\backslash$n1985 and 1994 and in the autumn of 1983 and the winter of 1984. Changes$\backslash$nof surface geometry were assessed from aerial photographs. The estimated$\backslash$nbasal shear stress changed little between 1982 and 1994. Nevertheless,$\backslash$nlarge changes in the relationship of subglacial water pressure and$\backslash$nsurface velocity were observed, which cannot be reconciled with the$\backslash$nmost commonly used sliding law unless it is modified substantially$\backslash$nConsideration of possible reasons indicates that a change in the$\backslash$nsubglacial drainage system occurred, probably involving a change$\backslash$nin the degree of cavity interconnection. Isolated cavities damp the$\backslash$nvariations in sliding velocity that normally result from changes$\backslash$nin water pressure, because the pressure in isolated cavities decreases$\backslash$nas the sliding speed increases. In contrast, by transmitting water-pressure$\backslash$nfluctuations to a larger area of the bed, interconnected cavities$\backslash$namplify the effect of water-pressure fluctuations on sliding speed.$\backslash$nThus, we suggest that an observed decrease in velocity (for a given$\backslash$nwater pressure) between 1982 and 1994 was a consequence of a decrease$\backslash$nin the interconnectedness of the subglacial cavity system.}, isbn = {0022-1430}, issn = {00221430}, doi = {10.1017/CBO9781107415324.004}, author = {Iken, A. and Truffer, M.} }