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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 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. 

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 George VI Sound is an ~600 km‐long curvilinear channel on the west coast of the southern Antarctic Peninsula separating Alexander Island from Palmer Land. The Sound is a geologically complex region presently covered by the George VI Ice Shelf. Here we model the bathymetry using aerogravity data. Our model is constrained by water depths from seismic measurements. We present a crustal density model for the region, propose a relocation for a major fault in the Sound, and reveal a dense body, ~200 km long, flanking the Palmer Land side. The southern half of the Sound consists of two distinct basins ~1,100 m deep, separated by a −650 m‐deep ridge. This constricting ridge presents a potential barrier to ocean circulation beneath the ice shelf and may account for observed differences in temperature‐salinity (T‐S) profiles. 

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. 

Abstract From 2015 to 2017, theROSETTA‐Ice project comprehensively mapped Antarctica's Ross Ice Shelf using IcePod, a newly developed aerogeophysical platform. The campaign imaged the ice‐shelf surface with lidar and its internal structure with ice‐penetrating radar. TheROSETTA‐Ice data was combined with pre‐existing ice surface and bed topography digital elevation models to create the first augmented reality (AR) visualisation of the Antarctic Ice Sheet, using the Microsoft HoloLens. TheROSETTA‐Ice datasets support cross‐disciplinary science that aims to understand 4D processes, namely the change of 3D ice‐shelf structures over time. The work presented here usesARto visualise this dataset in 3D and highlights howARcan be simultaneously a useful research tool for interdisciplinary geoscience as well as an effective device for science communication education. 

Abstract Basal melting of ice shelves is a major source of mass loss from the Antarctic Ice Sheet. In situ measurements of ice shelf basal melt rates are sparse, while the more extensive estimates from satellite altimetry require precise information about firn density and characteristics of near‐surface layers. We describe a novel method for estimating multidecadal basal melt rates using airborne ice penetrating radar data acquired during a 3‐year survey of the Ross Ice Shelf. These data revealed an ice column with distinct upper and lower units whose thicknesses change as ice flows from the grounding line toward the ice front. We interpret the lower unit as continental meteoric ice that has flowed across the grounding line and the upper unit as ice formed from snowfall onto the relatively flat ice shelf. We used the ice thickness difference and strain‐induced thickness change of the lower unit between the survey lines, combined with ice velocities, to derive basal melt rates averaged over one to six decades. Our results are similar to satellite laser altimetry estimates for the period 2003–2009, suggesting that the Ross Ice Shelf melt rates have been fairly stable for several decades. We identify five sites of elevated basal melt rates, in the range 0.5–2 m a⁻¹, near the ice shelf front. These hot spots indicate pathways into the sub‐ice‐shelf ocean cavity for warm seawater, likely a combination of summer‐warmed Antarctic Surface Water and modified Circumpolar Deep Water, and are potential areas of ice shelf weakening if the ocean warms.