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{"Abstract":["The PPT survey extended from the Ross Ice Shelf, southward over the TAM along 150W between the Scott and Reedy Glaciers, and through the South Pole. Approximately 15,000 line km were flown. North-south oriented transects were flown 10 km apart and west-east tie lines were flown with a 30 km line spacing. Fifteen km long transect 'run-ins' and 'run-outs' were added to each line, thus ensuring data collection to survey boundaries. Laser altimetry, ice-penetrating radar, gravity and magnetic field intensity data were collected. This work was funded by NSF-OPP grant 9615832 with the project title: Collaborative Research: Contrasting Architecture and Dynamics of the Transantarctic Mountains (Pensacola-Pole Transect). Principal Investigators were D.D. Blankenship, University of Texas Institute for Geophysics, and R.E. Bell and W.R. Buck, Lamont-Doherty Earth Observatory.\n<br>\n<br>\nThis work was conducted by the Support Office for Aerogeophysical Research (SOAR) NSF facility under cooperative agreement OPP-9319379. The 1998/1999 field season <a href="http://hdl.handle.net/2152/65412"> report </a>(Holt et al 1999) describes the field work in more detail.\n<br>\n<br>\nThese data are gridded orthogonal data with a point every 850 m. Data is in a space delimited ASCII table with three columns: Longitude, Latitude and geophysical observation. Grids are smoothed using a Gaussian filter (2.125 km for gravity, magnetic field anomaly, surface elevation and 8.5 km for ice thickness) and surfaced using a bicubic spline method.\n<br>\nObservations include:\n<ol>\n<li> Bed elevation (m, WGS-84) </li> \n<li> Gravity disturbance (mGal, WGS-84) </li> \n<li> Ice Thickness (m) </li> \n<li> Laser Derived Surface Elevation (m, WGS-84) </li> \n<li> Magnetic Anomaly (nT, IGRF) </li> \n<li> Radar Derived Surface Elevation (m, WGS-84) </li> \n</ol>\nA browse image is included. \n<br><br>\n<i>Acknowledgement: </i><br>\nIn keeping with NSF Grant Policy, any publication using these data (including web documents) must contain the following acknowledgment: "This material is based on work supported by the National Science Foundation under cooperative agreement OPP-9319379." Also, any oral presentation utilizing these materials should acknowledge the support of the National Science Foundation. In addition, we request that any oral presentation, web page or publication also acknowledge SOAR and the University of Texas. A suitable citation for PPT data is:\n<br>\n<i>Davis, M.B., 2001, Subglacial Morphology and Structural Geology in the Southern Transantarctic Mountains from Airborne Geophysics, M.S. Thesis, Univ. of Texas, 133 pp.<a href="http://dx.doi.org/10.26153/tsw/2786">doi:10.26153/tsw/2786</a></i>\n<br>\nThese data represent the data that was hosted on the UTIG webpage at https://www-udc.ig.utexas.edu/external/facilities/aero/data/soar/PPT/SOAR_ppt.htm."]} 

Abstract Sít’ Tlein (Malaspina Glacier), located in Southeast Alaska, has a complex flow history. This piedmont glacier, the largest in the world, is fed by three main tributaries that all exhibit similar flow patterns, yet with varying surge cycles. The piedmont lobe is dramatically reshaped by surges that occur at approximately decadal timescales. By combining historical accounts with modern remote sensing data, we derive a surge history over the past century. We leverage the Stochastic Matrix Factorization, a novel data analysis and interpolation technique, to process and interpret large datasets of glacier surface velocities. A variant of the Principal Component Analysis allows us to uncover spatial and temporal patterns in ice dynamics. We show that Sít’ Tlein displays a wide range of behaviors, spanning quiescence to surge with seasonal to decadal variations of ice flow direction and magnitude. We find that in the lobe, surges dominate the velocity dataset’s variance (spanning 1984–2021), while seasonal variations represent a much smaller part of the variance. However, despite the regular surge pulses, the glacier lobe is far from equilibrium, and widespread retreat of the glacier is inevitable, even without further climate warming. 

Abstract. Sít' Tlein, located in the St. Elias Range, which straddles Alaska's Wrangell–St. Elias National Park and Kluane National Park in the Yukon, is the world's largest piedmont glacier. Sít' Tlein has thinned considerably over 30 years of altimetry, yet its low-elevation piedmont lobe has remained intact in contrast to the glaciers that once filled neighboring Icy and Disenchantment bays. In an effort to forecast changes to Sít' Tlein over decadal to centennial timescales, we take a data-constrained dynamical modeling approach in which we infer the parameters of a higher-order model of ice flow – the bed elevation, basal traction, and surface mass balance – with a diverse but spatiotemporally sparse set of observations including satellite-derived, time-varying velocity fields; radar-derived bed and surface elevation measurements; and in situ and remotely sensed observations of accumulation and ablation. Nonetheless, such data do not uniquely constrain model behavior, so we adopt an approximate Bayesian approach based on the Laplace approximation and facilitated by low-rank parametric representations to quantify uncertainty in the bed, traction, and mass balance fields alongside the induced uncertainty in model-based predictions of glacier change. We find that Sít' Tlein is considerably out of balance with contemporary (and presumably future) climate, and we expect its piedmont lobe to largely disappear over the coming centuries. If warming ceases, and surface mass balance remains at 2023 levels, then by 2073 (2173) we forecast a mass loss (expressed in terms of 95 % credible interval) of 323–444 km3 (546–728 km3). If instead surface mass balance continues to change at the same rate as inferred over the historical period, then we forecast a 2073 (2173) mass loss of 383–505 km3 (740–900 km3). In either case, the resulting retreat and subsequent replacement of glacier ice with a marine embayment or lake will yield a significant modification to the regional landscape and ecosystem. 

Abstract We present Bedmap3, the latest suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60 °S. Bedmap3 incorporates and adds to all post-1950s datasets previously used for Bedmap2, including 84 new aero-geophysical surveys by 15 data providers, an additional 52 million data points and 1.9 million line-kilometres of measurement. These efforts have filled notable gaps including in major mountain ranges and the deep interior of East Antarctica, along West Antarctic coastlines and on the Antarctic Peninsula. Our new Bedmap3/RINGS grounding line similarly consolidates multiple recent mappings into a single, spatially coherent feature. Combined with updated maps of surface topography, ice shelf thickness, rock outcrops and bathymetry, Bedmap3 reveals in much greater detail the subglacial landscape and distribution of Antarctica’s ice, providing new opportunities to interpret continental-scale landscape evolution and to model the past and future evolution of the Antarctic ice sheets. 

The following dataset includes transient electromagnetic (TEM) data collected from the foreland region surrounding the front of the Malaspina Glacier, Alaska. This dataset was collected during the Summer of 2021 for the purpose of identifying regions within the forelands that contained buried stagnant glacial ice, and the thickness of the ice deposits. 

Abstract Debris‐covered glaciers (DCG) and rock glaciers have been increasingly studied in recent years because of the role they play within local watersheds, glacial ablation models due to climate change, and as analogs for buried ice features on planetary bodies such as Mars. Characterizing the supraglacial debris layer is a large part of these efforts. Geophysical exploration of DCG has mostly excluded active seismic methods, with the exception of refraction studies, due to the attenuating properties of the debris cover and field survey efficiency. We evaluate the accuracy, field efficiency, and effectiveness of seismic refraction, reflection, and surface‐wave surveys for determining the elastic properties of the debris layer and any underlying layers on DCG using the Sourdough Rock Glacier in Southcentral Alaska as a test site. We provide evidence for imaging an ultra‐shallow seismic reflection from the bottom of the loose debris layer using ultra‐dense receiver arrays and compare it to ground‐penetrating radar (GPR) images taken along the same profiles. We also detail how reliable dispersion curve images can be extracted from the surface wave package of the seismic data using the multi‐channel analysis of surface waves technique, which allows for the (s)‐wave profile to be inverted for. We find this could be a valuable addition to the toolbox of future geophysical investigations on DCG. 

Observing damage and documenting successful performance of buildings and other structures. Classes include residential, commercial, and power infrastructure. Methodologies include detailed damage assessments in Fulcrum, deployment of UAS for high-resolution aerial imagery, and deployment of surface-level panoramic imaging devices. Hazard indicators were also captured. 

We present here Bedmap3, the latest suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of Antarctica south of 60degS. Bedmap3 incorporates and adds to all post-1950s datasets previously used for Bedmap1 and Bedmap2, including 84 new aero-geophysical surveys by 15 data providers, an additional 52 million data points and 1.9 million line-kilometres of measurement. This has filled notable gaps in East Antarctica, including the South Pole and Pensacola basin, Dronning Maud Land, Recovery Glacier and Dome Fuji, Princess Elizabeth Land, plus the Antarctic Peninsula, West Antarctic coastlines, and the Transantarctic Mountains. Our new Bedmap3/RINGS grounding line similarly consolidates multiple recent mappings into a single, spatially coherent feature. Combined with updated maps of surface topography, ice shelf thickness, rock outcrops and bathymetry, Bedmap3 reveals in much greater detail the subglacial landscape and distribution of Antarctica's ice, providing new opportunities to interpret continental-scale landscape evolution and to model in detail the past and future evolution of the Antarctic ice sheets. Sponsored by the Scientific Committee on Antarctic Research (SCAR), the Bedmap3 Action group aims to produce a new map and datasets of Antarctic ice thickness and bed topography for the international scientific community. The associated Bedmap datasets are listed here: https://www.bas.ac.uk/project/bedmap/#data 

Abstract. One of the key components of this research has been the mapping of Antarctic bed topography and ice thickness parameters that are crucial for modelling ice flow and hence for predicting future ice loss andthe ensuing sea level rise. Supported by the Scientific Committee on Antarctic Research (SCAR), the Bedmap3 Action Group aims not only to produce newgridded maps of ice thickness and bed topography for the internationalscientific community, but also to standardize and make available all thegeophysical survey data points used in producing the Bedmap griddedproducts. Here, we document the survey data used in the latest iteration,Bedmap3, incorporating and adding to all of the datasets previously used forBedmap1 and Bedmap2, including ice bed, surface and thickness point data from all Antarctic geophysical campaigns since the 1950s. More specifically,we describe the processes used to standardize and make these and futuresurveys and gridded datasets accessible under the Findable, Accessible, Interoperable, and Reusable (FAIR) data principles. With the goals of making the gridding process reproducible and allowing scientists to re-use the data freely for their own analysis, we introduce the new SCAR Bedmap Data Portal(https://bedmap.scar.org, last access: 1 March 2023) created to provideunprecedented open access to these important datasets through a web-map interface. We believe that this data release will be a valuable asset to Antarctic research and will greatly extend the life cycle of the data heldwithin it. Data are available from the UK Polar Data Centre: https://data.bas.ac.uk (last access: 5 May 2023​​​​​​​). See the Data availability section for the complete list of datasets.