OpenSearch

Using the NASA EOSDIS Common Metadata Repository

Collection Search

  • Collaborative Research: Characteristics of Snow Megadunes and their Potential Effects on Ice Core Interpretation

    https://cmr.earthdata.nasa.gov/search/concepts/C1214621845-SCIOPS.xml
    Description:

    Field study and remote sensing measurements of an area of snow megadunes on the East Antarctic plateau provides a preliminary assessment of dune morphology, firn structure, and layering in the features. Snow megadunes are undulating variations in accumulation and surface texture, with wavelengths of 2 to 5 km and amplitudes up to 5 meters. The features cover 500,000 km2 of the East Antarctic plateau, occurring in areas of moderate regional slope and low accumulation on the flanks of the ice sheet between 2500 and 3800 meters elevation (Fahnestock et al., 2000). Our field area lies in the Byrd Glacier catchment region, near 80.78 degrees S, 124.5 degrees E, at an elevation of 2885 meters. Crest to crest separation near the field site averages 4.2 km. GPS topographic profiles show a 4 to 5 meter surface amplitude on a regional slope of about 0.001. This region contains some of the best examples of the megadune features that could be found in satellite mappings. Landsat images and aerial photography indicate the dunes consist of alternating surfaces of glaze and rough sastrugi with gradational boundaries. This pattern is oriented perpendicular to the mean wind direction, as modeled in katabatic wind studies (and partly confirmed by our brief observations). Glaze surfaces cover the leeward faces and troughs; rough sastrugi cover the windward faces and crests. The megadune pattern is crossed by smooth to eroded wind-parallel longitudinal dunes. Wind-eroded longitudinal dunes form spectacular 1-meter-high sastrugi in nearby areas. Dune structure at depth was profiled by ground-penetrating radar. The profile shows a sub-surface wave structure with amplitude of 5 to 8 m and a shift in the crest/trough pattern with depth consistent with upwind accretionary migration of the rough sastrugi patches. The layer pattern also indicates greatly reduced accumulation in glaze areas. The dune wave pattern is visible to the base of the profile, 40 meters below the surface. Given the very low accumulation rates for the area (1 to 4 cm at Vostok and nearby IGY-era snowpit studies), this thickness may represent the last few thousand years.

    Links: Temporal Extent: Spatial Extent:

    SCIOPS Short Name: scambos_0125570 Version ID: Not provided Unique ID: C1214621845-SCIOPS

  • Georectification of IKONOS image, January 2004, Heard Island

    https://cmr.earthdata.nasa.gov/search/concepts/C1214313763-AU_AADC.xml
    Description:

    NOTE - this record has been superseded by "SIC_266_267_ortho", which describes a more recent orthorectification of the same two images. Two IKONOS 2004 images (SIC 266 and 267) were chosen as the base images for the AAS2939 change detection project. The reason for choosing these images where that they were the earliest very high resolution (VHR) image with the least amount of cloud cover for which DGPS GCPs are available and identified on the image by Jenny Scott. The importance of having a base image to register all other images to is to allow change detection between images. The 2004 IKONOS image was resampled to a 0.6m resolution, in order to match the resolution of the Quickbird images (for future rectification and change detection).

    Links: Temporal Extent: Spatial Extent:
    Minimum Bounding Rectangle: -53.3 73.2 -52.9 73.9

    AU_AADC Short Name: SIC_266_267_georectification Version ID: 1 Unique ID: C1214313763-AU_AADC

  • Heard Island Radarsat Georeferencing Report, September 2002

    https://cmr.earthdata.nasa.gov/search/concepts/C1214313518-AU_AADC.xml
    Description:

    The aim of the project was to derive a number of control points that could be used to georeference two Radarsat scenes over Heard Island. Control points were derived from aerial photography covering various locations around the island, namely: Cape Gazert, Atlas Cove, Brown Lagoon, Manning Lagoon and Winston Lagoon. ERDAS Imagine with OrthoBase Pro photogrammatric software was used to ortho-rectify the aerial photography and extract values for the derived control points. ERDAS Imagine OrthoRadar was used to georeference the Radarsat images. The measurements taken from the aerial photography have been described in an earlier report.

    Links: Temporal Extent: Spatial Extent:
    Minimum Bounding Rectangle: -53.21 73.24 -52.95 73.9

    AU_AADC Short Name: Heard_RadarSat_georef Version ID: 1 Unique ID: C1214313518-AU_AADC

  • High-resolution Image-derived Grounding and Hydrostatic Lines for the Antarctic Ice Sheet

    https://cmr.earthdata.nasa.gov/search/concepts/C1407211681-SCIOPS.xml
    Description:

    This data set provides grounding line and hydrostatic line locations for the Antarctic coastline and islands around Antarctica. The data are derived using customized software to combine data from Landsat-7 imagery and Ice, Cloud, and land Elevation Satellite (ICESat) laser altimetry, which were primarily collected between 1999 to 2003. The data set also includes elevations along each line, selected from six candidate digital elevation models. The data were developed as part of the Antarctic Surface Accumulation and Ice Discharge (ASAID) project.

    Links: Temporal Extent: Spatial Extent:
    Minimum Bounding Rectangle: -80 -180 -60 180

    SCIOPS Short Name: NSIDC-0489 Version ID: 1 Unique ID: C1407211681-SCIOPS

  • High-resolution Image-derived Grounding and Hydrostatic Lines for the Antarctic Ice Sheet, Version 1

    https://cmr.earthdata.nasa.gov/search/concepts/C1386250691-NSIDCV0.xml
    Description:

    This data set provides grounding line and hydrostatic line locations for the Antarctic coastline and islands around Antarctica. The data are derived using customized software to combine data from Landsat-7 imagery and Ice, Cloud, and land Elevation Satellite (ICESat) laser altimetry, which were primarily collected between 1999 to 2003. The data set also includes elevations along each line, selected from six candidate digital elevation models. The data were developed as part of the Antarctic Surface Accumulation and Ice Discharge (ASAID) project.

    Links: Temporal Extent: Spatial Extent:
    Minimum Bounding Rectangle: -80 -180 -60 180

    NSIDCV0 Short Name: NSIDC-0489 Version ID: 1 Unique ID: C1386250691-NSIDCV0

  • IMS Daily Northern Hemisphere Snow and Ice Analysis at 1 km, 4 km, and 24 km Resolutions, Version 1

    https://cmr.earthdata.nasa.gov/search/concepts/C1386246258-NSIDCV0.xml
    Description:

    This data set provides maps of snow cover and sea ice for the Northern Hemisphere from February 1997 to the present from the National Ice Center's Interactive Multisensor Snow and Ice Mapping System (IMS). It is derived from a variety of data products including satellite imagery and in situ data. The data are provided in ASCII text and GeoTIFF formats in three different resolutions: 1 km, 4 km, and 24 km. Note: The IMS product is considered an operational product; however, NIC, who creates this product, does not guarantee availability or timely delivery of data via the NIC Web server. NSIDC, as the data archive, does not guarantee availability of this product via the NSIDC Web server. These servers should not be used to support operational observation, forecasting, emergency, or disaster mitigation operations, either public or private. Users with real-time operational needs should visit the NIC Web site and contact the National Ice Center Liaison to request access to their operational server.

    Links: Temporal Extent: Spatial Extent:
    Minimum Bounding Rectangle: 0 -180 90 180

    NSIDCV0 Short Name: G02156 Version ID: 1 Unique ID: C1386246258-NSIDCV0

  • Mass flux measurements across the margin of the Antarctic ice sheet

    https://cmr.earthdata.nasa.gov/search/concepts/C1214312644-AU_AADC.xml
    Description:

    Metadata record for data from ASAC Project 2318 See the link below for public details on this project. ---- Public Summary from Project ---- This project is a cooperative venture between Australian and Italian institutes in a study of the mass budget of a large sector of the East Antarctic ice sheet. The mass budget represents the difference between the net input of moisture from the ocean as snow accumulating on the surface and the discharge of ice from the grounded part of the ice sheet. Any mismatch between these input and out put terms produces a direct contribution to change in sea level. Measurements of ice thickness along the coastal margin of the grounded ice sheet, combined with velocity data derived from satellite remote sensing methods, will provide the first direct measurements of the total mass output for the part of the ice sheet draining through this sector of the coastline. The observations will also a baseline against which future change in the mass flux can be assessed. From the abstract of the referenced paper: An air-borne radio echo sounding survey was conducted over the Amery Ice Shelf, East Antarctica, in December 2003. Nine transverse profiles where obtained approximately normal to the flow of direction, together with one longitude profile for a total length of of flight lines of about 1000km. We determined the spatial distribution of the characteristics of the RES signal returned from the ice-water interface at the base of the shelf. The key characteristics are described by the amplitude of the echo and the slope of the leading edge of the returned pulse. For the mass flux we ice thickness values extracted from our RES data, and velocities derived form InSAR maximum coherence tracking in pairs of Radarsat SAR images, with control provided by surface measurements. We calculate the mass budget for a set of discrete areas bounded by our RES survey lines across the shelf, and flow-lines derived from the velocity field (modified in the across shelf components of the velocity) and from linear flow-features identified in the satellite images. using available estimates of the snow accumulation rate at the upper surface, and assuming the ice thickness and velocities are stationary in time, we attribute the mass imbalance within a sub-area to be the result of melt or freeze at the base of the shelf. Both, the distribution of values of melt-freeze rates, and of the characteristics basal echoes form distinct patterns that appear to be influenced by variations in the ice draft and conditions in the sub-shelf ocean cavity. We find a net melt regime associated with the deeper draft to the South and under the central part of the shelf, and net freeze conditions in the North and sides, particularly towards the western margin. the strength of the electromagnetic signals reflected from the ice water-interface shows a similar pattern of variation along all nine transverse profiles. We find a strong association with basal mass balance Summary of progress 2004/2005 The field phase of the project was completed in 03/04 season. Current work involves analysis and interpretation of the Radio Echo Sounding measurements of ice thickness. An initial appraisal was completed of all RES data. A coarsely-spaced set of preliminary estimates of ice thickness were extracted and merged with GPS position data for generation of a first-cut distribution of ice thickness round a large sector of the ice sheet margin. New analysis systems have been developed and to-date applied to 25% of the data for extraction of detail ice thickness information and characteristics of the radar echoes. An initial assessment of all the RES data collected during the field work has been completed. Preliminary ice thickness estimates have been extracted at coarse spacing along the flight lines to generate a first-cut assessment of the ice thickness distribution for planning next phases of the project and for assessment of the need for additional field work. Those data have been merged with GPS position data collected at a ten-second time-interval along the flight track. This work has been carried out primarily by the Italian investigators. In Australia, software systems have been developed to carry out the full-resolution analysis of the digital RES data. This analysis system is based on developments undertaken in AAS project # 2224. To-date, data analysis using this system has been completed for all flights over the Amery Ice Shelf, and analysis of flights over the Law Dome, Totten Glacier, Moscow University Ice Shelf is nearing completion. As part of the depth extraction procedure, algorithms have been developed and implemented that allow extraction of the echo characteristics for an horizon identified in the digital record. For the echoes forming that horizon, the leading-edge slope, peak and base power, echo-width, and height are extracted. These characteristics vary with the characteristics of the reflector in the ice and can be related to roughness, reflectivity coefficient (dielectric contrast), etc. For the flight lines over the Amery Ice Shelf we have found a spatially coherent pattern in the variation in the echo-height and leading-edge-slope of the basal echo that appears to correspond to variation between individual flow-bands of reflection properties of the ice-water interface. This is a recent preliminary finding and work is continuing with these aspects. This detail analysis phase of the project is being carried out jointly by N Young and A Forieri during a 5-month visit by A Forieri to the ACE CRC funded by PNRA (Italy) and ACE CRC.

    Links: Temporal Extent: Spatial Extent:
    Minimum Bounding Rectangle: -70 62 -62 159

    AU_AADC Short Name: ASAC_2318 Version ID: Not provided Unique ID: C1214312644-AU_AADC

  • MEaSUREs Annual Antarctic Ice Velocity Maps 2005-2017 V001

    https://cmr.earthdata.nasa.gov/search/concepts/C1458152674-NSIDC_ECS.xml
    Description:

    This data set, part of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) program, provides 12 annual maps of Antarctic ice velocity from 2005-2017. The maps are assembled using SAR data from the Japanese Space Agency's (JAXA) ALOS PALSAR, the European Space Agency's (ESA) ENVISAT ASAR and Copernicus Sentinel-1, the Canadian Space Agency's (CSA) RADARSAT-1, RADARSAT-2, the German Aerospace Agency's (DLR) TerraSAR-X (TSX) and TanDEM –X (TDX), and the U.S. Geological Survey's (USGS) Landsat-8 optical imagery acquired between 2005 and 2017. See <a href="https://nsidc.org/data/measures/aiv">Antarctic Ice Sheet Velocity and Mapping Data</a> for related data.

    Links: Temporal Extent: Spatial Extent:
    Minimum Bounding Rectangle: -90 -180 -60 180

    NSIDC_ECS Short Name: NSIDC-0720 Version ID: 1 Unique ID: C1458152674-NSIDC_ECS

  • MEaSUREs Antarctic Boundaries for IPY 2007-2009 from Satellite Radar V002

    https://cmr.earthdata.nasa.gov/search/concepts/C1454773262-NSIDC_ECS.xml
    Description:

    This data set, part of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) program, provides maps of Antarctic ice shelves, Antarctic basins, and the Antarctic coastline. The maps are assembled from 2008-2009 ice-front data from the Japan Aerospace Exploration Agency's (JAXA) ALOS PALSAR and European Space Agency's ENVISAT ASAR data, acquired during International Polar Years 2007-2009 (IPY); the InSAR-based grounding line data (MEaSUREs Antarctic Grounding Line from Differential Satellite Radar Interferometry), augmented with other grounding line sources; the Antarctic ice velocity map (MEaSUREs InSAR-Based Antarctica Ice Velocity Map); and the Bedmap-2 DEM. See <a href="https://nsidc.org/data/measures/aiv">Antarctic Ice Sheet Velocity and Mapping Data</a> for related data.

    Links: Temporal Extent: Spatial Extent:
    Minimum Bounding Rectangle: -90 -180 -60 180

    NSIDC_ECS Short Name: NSIDC-0709 Version ID: 2 Unique ID: C1454773262-NSIDC_ECS

  • MEaSUREs Antarctic Grounding Line from Differential Satellite Radar Interferometry V002

    https://cmr.earthdata.nasa.gov/search/concepts/C1573480652-NSIDC_ECS.xml
    Description:

    This data set, part of the NASA Making Earth System Data Records for Use in Research Environments (MEaSUREs) program, provides 22 years of comprehensive high-resolution mapping of grounding lines in Antarctica from 1992 to 2014. The data were derived using differential satellite synthetic aperture radar interferometry (DInSAR) measurements from the following platforms: Earth Remote Sensing Satellites 1 and 2 (ERS-1 and ERS-2), RADARSAT-1, RADARSAT-2, the Advanced Land Observing System Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR), Cosmo Skymed, and Copernicus Sentinel-1. See <a href="https://nsidc.org/data/measures/aiv">Antarctic Ice Sheet Velocity and Mapping Data</a> for related data.

    Links: Temporal Extent: Spatial Extent:
    Minimum Bounding Rectangle: -90 -180 -60 180

    NSIDC_ECS Short Name: NSIDC-0498 Version ID: 2 Unique ID: C1573480652-NSIDC_ECS