Coastal and Terminus History of the Eastern Amundsen Sea Embayment, West Antarctica, 1972 to 2011

This data set provides a history of coastal change in the Eastern Amundsen Sea Embayment, based primarily on imagery from the NASA/USGS Landsat satellite, with additional data from the European Remote Sensing (ERS) satellite and historical coastline data derived from published aerial photography.

Table of Contents

  1. Contacts and Acknowledgments
  2. Detailed Data Description
  3. Data Access and Tools
  4. Data Acquisition and Processing
  5. References and Related Publications
  6. Document Information

Citing These Data

We kindly request that you cite the use of this data set in a publication using the following citation example. For more information, see our Use and Copyright Web page.

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

Overview

Platform

Landsat
European Remote Sensing (ERS) satellite
Aerial Photography

Sensor

Thematic Mapper (TM)

Synthetic Aperture Radar (SAR)

Spatial Coverage

Eastern Amundsen Sea Embayment, West Antarctica
Southernmost Latitude: 76° S
Northernmost Latitude: 74° S
Westernmost Longitude: 110° W
Easternmost Longitude: 100° W

Spatial Resolution

~200 m

Temporal Coverage

December 1972 to 09 November, 2011, with some additional data from 1947, 1963, and 1966, from other sources.

Parameters

Coastline Locations

Glacier Terminus Histories

Mosaic

Data Format

Coastlines: Environmental Systems Research Institute (ESRI) shapefiles and Comma Separated Value (.csv) text files
Terminus Histories: Text (.csv) files.

Metadata Access

View Metadata Record

Data Access

FTP

1. Contacts and Acknowledgments

Investigators

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

Technical Contact

NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449  USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
e-mail: nsidc@nsidc.org

Acknowledgements

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

2. 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

map of data showing evolution of coastline
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

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

 

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 (e.g., 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 (e.g., 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.

File Size

Files range in size from 3 KB to 77 KB.

Volume

Total volume of the data set is 23 MB.

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.

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.

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)

3. Data Access and Tools

Data Access

Data are available via FTP.

Software and Tools

Data are accessible using image processing software and Matlab.

4. 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.

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.

5. References and Related Publications

MacGregor, J.A., G.A. Catania, M.S. Markowski and A.G. Andrews. 2012. Widespread Rifting and Retreat of Ice Shelf Margins in the Eastern Amundsen Sea Embayment Between 1972 and 2011, Journal of Glaciology, 58(209), 458-466, doi:10.3189/2012JoG11J262.

Related Web Sites

6. Document Information

Acronyms and Abbreviations

The acronyms used in this document are listed in Table 3.

Table 3. Acronyms and Abbreviations
Acronym Description
AGDC Antarctic Glaciological Data Center
CSV Comma Separated Value
ERS European Remote Sensing
ESRI Earth System Research Institute
FTP File Transfer Protocol
MOA Mosaic of Antarctica
NSF National Science Foundation
OPP Office of Polar Programs
SAR Synthetic Aperture Radar

Document Creation Date

May 2012

Document URL

http://nsidc.org/data/docs/agdc/nsidc0522_macgregor/index.html