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Data Set ID:
NSIDC-0522

Coastal and Terminus History of the Eastern Amundsen Sea Embayment, West Antarctica, 1972 - 2011, Version 1

This data set provides a coastline history of the eastern Amundsen Sea Embayment and terminus histories of its outlet glaciers derived from those coastlines. These outlet glaciers include Smith, Haynes, Thwaites, and Pine Island Glaciers. The coastlines were derived from detailed tracing of Landsat imagery between late 1972 and late 2011 (at a scale of 1:50,000). The data set also uses some additional data from other sources. The terminus histories are calculated as the intersections between these coastlines and 1996 flowlines.

Data are available via FTP in ESRI shapefile and comma separated value (.csv) formats.

Geographic Coverage

Spatial Coverage:
  • N: -74, S: -76, E: -100, W: -110

Spatial Resolution: Not Specified
Temporal Coverage:
  • 1 January 1947 to 31 December 1966
  • 1 December 1972 to 30 November 2011
  • 1 January 1992 to 31 December 1998
Temporal Resolution: Not specified
Parameter(s):
  • Geomorphology > Coastal Landforms/Processes
  • Glaciers/Ice Sheets > Glaciers
  • Glaciers/Ice Sheets > Glacier Topography/Ice Sheet Topography
Platform(s) ERS-1, LANDSAT, LANDSAT-5
Sensor(s): CAMERAS, SAR, TM
Data Format(s):
  • MATLAB
  • ESRI Shapefile
  • ASCII Text
Version: V1
Data Contributor(s): Joseph MacGregor, Ginny Catania, Michael Markowski, Alan Andrews

Data Citation

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

MacGregor, J. A., G. Catania, M. Markowski, and A. G. Andrews. 2012. Coastal and Terminus History of the Eastern Amundsen Sea Embayment, West Antarctica, 1972 - 2011, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5CC0XNK. [Date Accessed].

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Detailed Data Description

This data includes coastlines and glacier terminus histories, derived from manual tracing of Landsat and ERS SAR imagery. The coastline data are provided as ESRI shapefiles, while the terminus data are provided as text files in Comma Separated Value (.csv) format. The data set includes scene information in .csv format, that describe the mosaics from which the coastline and terminus data were derived. It also includes a Matlab (.m) script, useful for reading the data in Matlab.

Data Image

Figure 1. Evolution of the Amundsen Sea Embayment coastline from 1972 to 2011
Credit: MacGregor, et. al. 2012
Format

Coastlines: Environmental Systems Research Institute (ESRI) shapefiles and Comma Separated Value (.csv) text files
Terminus Histories: Text (.csv) files
Mosaic Information: Text (.csv) files
Matlab Script: .m file

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File and Directory Structure

Data are available on the FTP site in ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0522_macgregor_V01/. This directory contains four text files, listed below, and a sub-folder with the coastline data in ESRI shapefile format.

Table 1. File Description
File/Folder Name Description
ase_load.m Matlab file for loading the coastline shapefiles in Matlab
ase_mosaic_ers.csv

Text file containing the scene information for all ERS data used in the data set

ase_mosaic_landsat.csv Text file containing the scene information for all Landsat data used in the data set
ase_terminus_hist.csv Text file containing the terminus data
ase_coastline_shapefiles Folder containing the shapefiles with the coastline data
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File Naming Convention

Text Files

Text files are named according to the following convention.

ase_xxxx_aaaa.csv

Where:

Table 2. File Naming Convention for Text Files
Variable Description
ase Amundsen Sea Embayment
xxxx

Data Type:

  • mosaic: information on all scenes used to make the mosaic
  • terminus: data on glacier termina derived from ERS and Landsat data
aaaa

Source or data type:

  • landsat: Landsat data
  • ers: ERS data
  • hist: History data
csv Comma Separated Value file extension

Shapefiles

Shapefile names follow the convention described in the mosaic table files (ase_mosaic_landsat.csv and ase_mosaic_ers.csv). Mosaic years are followed by a one- or two-character identifier, which specifies whether the mosaic was formed from scenes in the first (a) or second (b) half of the calendar year, and, if there are multiple mosaics for a given half of that calendar, the chronological order of each mosaic. For example, 2000a1, 2000a2, 2000a3.

Where available, an outline of the detached Thwaites Glacier Tongue is also included. These files end in "_tongue", and their year labeling follows the same style as for the coastlines. If more than one detached ice tongue is outlined. For example, late 1972, 2010-2011, then these files are sub-labeled as ...tongue1 or ...tongue2.

Matlab

The Matlab script, ase_load.m, is an example of how to load and plot the shapefile and terminus history data into Matlab.

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File Size

Files range in size from 3 KB to 77 KB.

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Volume

Total volume of the data set is 23 MB.

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Spatial Coverage

This data set spans the eastern Amundsen Sea Embayment in West Antarctica, including Thwaites Glacier, Pine Island Glacier, and Smith Glacier.

Southernmost Latitude: 76° S 
Northernmost Latitude: 74° S 
Westernmost Longitude: 110° W
Easternmost Longitude: 100° W

Spatial Resolution

~200 m: Estimated resolution of the data set is based on the differences between satellite scenes used, and ice flow speeds. The Landsat data resolution ranges from 60 m to 15 m. For more information see MacGregor, et. al., 2012.

Projection and Grid Description

Shapefiles: Standard polar stereographic projection for Antarctica. The standard parallel is 71 degrees South.

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Temporal Coverage

Landsat Data: 158 scenes acquired between December 1972 and November 2011

ERS SAR Data: 38 scenes acquired between 1992 and 1998.

Aerial Photography: For Pine Island Glacier only, the terminus history data include positions derived from published coastlines, which themselves were derived from 1947 and 1966 aerial photography and 1963 satellite photography.

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Parameter or Variable

This data set contains coastline positions for the Amundsen Sea Embayment, in polar stereographic coordinates (x/y, km), and terminus position (km) for a number of glaciers in the region

Parameter Description

Coastline

Coastline data are provided in ESRI shapefile format, organized by year.

Terminus Histories

Terminus History data are provided in comma separated value (.csv) text file format. NaN indicates missing data.

Table 2. Parameters in the ase_terminus_hist.csv File
Column Number Description
1 Mosaic date, as Matlab date number. Mosaic dates are the mean value for the scenes used to create the mosaic from which the coastline was traced.
2 Mosaic date, as mm/dd/yy. Mosaic dates are themean value for the scenes used to create the mosaic from which the coastline was traced.
3 Terminus position, Smith Glacier / Crosson Ice Shelf (km)
4 Terminus position, Haynes Glacier (km)
5 Terminus position, Thwaites Glacier Tongue (km)
6 Terminus position, Thwaites Glacier eastern ice shelf (km)
7 Terminus position, Pine Island Glacier ice shelf (km)
8 Terminus position, Pine Island Glacier ice shelf, flowband method, (km)
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Software and Tools

Software and Tools

Data are accessible using image processing software and Matlab.

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Data Acquisition and Processing

Data Acquisition Methods

Data were acquired from the NASA/USGS Landsat satellites, the European Remote Sensing Satellite (ERS), and aerial photography.

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Derivation Techniques and Algorithms

Coastlines

Coastlines were traced manually on Landsat and ERS/SAR mosaics, at a scale of 1:50,000. For more details, see MacGregor et. al. 2012.

Terminus Positions

Except where noted, terminus positions are calculated as the linearly interpolated intersection of traced coastline with fixed flowlines determined from a 1996 surface velocity map. The terminus position values are relative to the intersection of the Mosaic of Antarctica (MOA) grounding line with the flowline. The flowlines used are shown in Figure 1a of MacGregor et. al. 2012, and the terminus position data are identical to those shown in Figure 3 of that same study. Note that the flowlines used are not provided, and that the coastlines of these glaciers often jagged, with the notable exception of Pine Island Glacier. The flowline-derived terminus positions should therefore be considered only one possible representation of the terminus history, with the ice-shelf margins being the primary example of where these terminus histories break down. However, we experimented with the position of the flowlines to find those that best captured the main calving behavior of each glacier. For more details, refer to MacGregor et. al. 2012.

For Pine Island Glacier, the terminus position is also calculated using a flowband method, as shown in Fig. 4a of MacGregor et. al. 2012 and described therein.

Not-a-number (NaN) values for terminus position indicate that the flowline used for a given glacier (column) did not intersect the traced coastline for that date (row). Terminus positions for Pine Island Glacier in 1947, 1963, and 1966 were derived from published coastlines referenced in MacGregor et al. 2012, and they are not included in the accompanying set of coastline shapefiles.

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References and Related Publications

Contacts and Acknowledgments

Dr. Joseph A. MacGregor, Dr. Ginny Catania, Dr. Michael Markowski, and Dr. Alan G. Andrews.
Institute for Geophysics
University of Texas at Austin 
J.J. Pickle Research Campus, Bldg. 196
10100 Burnet Rd. (R2200)
Austin, TX 78758-4445

Acknowledgements: 

This research was supported by the National Science Foundation (NSF) Office of Polar Programs (OPP) grant number 0739654.

Document Information

DOCUMENT CREATION DATE

May 2012

DOCUMENT REVISION DATE

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