This data set consists of experimental output from a higher-order finite-element model that was utilized in conjunction with existing data sets to isolate essential physical processes affecting Thwaites Glacier (TG) in the Amundsen Sea Embayment (ASE) of West Antarctica.
Get Data
DOWNLOADING DATA VIA FTP
Data can be downloaded through a Web browser or command line via FTP. When using a Web browser, the FTP link first directs you to an Optional Registration Form that if filled out, will allow you to receive notifications about updates or processing changes related to that specific data set. After completing the Optional Registration Form, the FTP directory becomes available. For additional help downloading data through an FTP client, go to the How to access data using an FTP client support page.
Synthesis of Thwaites Glacier Dynamics: Diagnostic and Prognostic Sensitivity Studies of a West Antarctic Outlet System, Version 1
Geographic Coverage
Spatial Coverage: |
|
---|---|
Spatial Resolution: | Not Specified |
Temporal Coverage: |
|
Temporal Resolution: | Not specified |
Parameter(s): |
|
Platform(s) | Not specified |
Sensor(s): | Not specified |
Data Format(s): |
|
Version: | V1 |
Data Contributor(s): | Byron Parizek, Donald Blankenship, Todd Dupont, John Holt |
Metadata XML: | View Metadata Record |
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.
Parizek, B. R. et al. 2014. Synthesis of Thwaites Glacier Dynamics: Diagnostic and Prognostic Sensitivity Studies of a West Antarctic Outlet System, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N58913TN. [Date Accessed].Literature Citation
As a condition of using these data, we request that you acknowledge the author(s) of this data set by referencing the following peer-reviewed publication.
Parizek, B. R.. 2013. Dynamic (in)stability of Thwaites Glacier, West Antarctica, Journal of Geophysical Research-Earth Surface. 118. 638-655. http://dx.doi.org/10.1002/jgrf.20044
Detailed Data Description
A higher-order finite-element model is utilized to explore the effects of ice-ocean interactions, ice-shelf buttressing, basal properties (stress distribution, topography, sliding, rheology, and grounding-zone processes), surface mass balance, and inland dynamic perturbations on the present and future dynamics of Thwaites Glacier. This particular model is ideally suited for the broad nature of this investigation, as it incorporates efficient yet regionally reasonable simplifications of the stress field (higher-order), system geometry (2-d flowline), and mass-momentum-ocean coupling (mechanical ice and plume ocean). The model is constrained by data sets (including regional maps of ice thickness, surface elevation, basal topography, and ice surface velocity) and geophysical data analyses (including increasing the spatial resolution of surface and basal elevations and characterizing the sub-glacial interface of grounded ice as well as the grounding-zone transition between grounded and floating ice). Figure 1 shows the model domain for the different elements of the model.
The simulation for each process is described in Parizek et al. (2013).

The data files are in Network Common Data Form (netCDF) format and are identified with the .nc
file extension.
Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0619_parizek/
directory. Within this directory, there is one folder, Thwaites_NSF
, which contains 23 NetCDF (.nc
) files.
The netCDF files are named according to the the Sea-level Response to Ice Sheet Evolution (SeaRISE) naming conventions outlined at http://websrv.cs.umt.edu/isis/index.php/Output_Format.
This section explains the file naming convention used for this product with examples.
Example File Names:BPA1_A_D2_C1_E0.nc
NNNn_X_Dd_Xx_Ee.nc
Refer to Table 1 for the valid values for the file name variables listed above.
Variable | Description |
---|---|
NNN | three letter characters for name, either a group name like PSU for Penn State, or an individual name made up by the first character of the first name followed by the first two characters of the last name |
n | model number (n = 1 if you have only one model) |
X | experiment category, either A for Antarctica, or G for Greenland |
D | denotes model dimension |
d | model dimension identifier (1 for 1D, 2 for 2D, 3 for 3D) |
X | C denotes model climate treatment S denotes model sliding treatment M denotes model ocean treatment |
x |
c = model climate identifier (1 for constant climate, 2 for 4th Assessment future climate forcing (see below) s = model sliding identifier (1 for sliding forcing with experiment number (see below), m = model ocean forcing identifier (1 for ocean forcing with experiment number (see below), |
E | denotes experiment category |
e | experiment number (0 for no forcing, versus >0 for forcing experiments as detailed above) |
Example File Names:BPA1_A_D2_T3_E1.nc
NNNn_X_Dd_Tt_Ee.nc
Refer to Table 2 for the valid values for the file name variables listed above.
Variable | Description |
---|---|
NNN | three letter characters for name, either a group name like PSU for Penn State, or an individual name made up by the first character of the first name followed by the first two characters of the last name |
n | model number (n = 1 if you have only one model) |
X | experiment category, either A for Antarctica, or G for Greenland |
D | denotes model dimension |
d | model dimension identifier (1 for 1D, 2 for 2D, 3 for 3D) |
T | denotes combinations of climate, sliding, and/or ocean treatments |
t | multiple forcing identifier (1 for climate, sliding, and ocean, 2 for climate and sliding, and 3 for climate and ocean forcings with experiment number (see below), e assigned with the following amplification factors if that particular forcing is included 1= 1x AR4, 2x u(b), 2m/yr subshelf melt rates 2= 1x AR4, 2x u(b), coupled ice-ocean melt rates 3_T1= 1x AR4, coupled ice-ocean melt rates, and higher resolution topography around the grounding zone |
E | denotes experiment category |
e | experiment number (0 for no forcing, versus >0 for forcing experiments as detailed above) |
Example File Names:BPA1_A_D2_T3_E4_GZ1.nc
NNNn_X_Dd_Tt_Ee_GZx.nc
Refer to Table 3 for the valid values for the file name variables listed above.
Variable | Description |
---|---|
NNN | three letter characters for name, either a group name like PSU for Penn State, or an individual name made up by the first character of the first name followed by the first two characters of the last name |
n | model number (n = 1 if you have only one model) |
X | experiment category, either A for Antarctica, or G for Greenland |
D | denotes model dimension |
d | model dimension identifier (1 for 1D, 2 for 2D, 3 for 3D) |
T | denotes combinations of climate, sliding, and/or ocean treatments |
t | multiple forcing identifier (1 for climate, sliding, and ocean, 2 for climate and sliding, and 3 for climate and ocean forcings with experiment number (see below), e assigned with the following amplification factors if that particular forcing is included 4_GZ1 = 3_T1 with enhanced basal melting and reduced friction within a 5-km grounding zone 5_GZ2 = 3_T1 with enhanced basal melting and reduced friction within a 6-km grounding zone 6_GZ3 = 3_T1 with enhanced basal melting and reduced friction within a 7-km grounding zone 7_GZ4 = 3_T1 with enhanced basal melting and reduced friction within a 10-km grounding zone 8_GZ5 = 3_T1 with enhanced basal melting and reduced friction within a 6-km grounding zone and the lower-resolution SeaRise basal topography around the grounding zone |
E | denotes experiment category |
e | experiment number (0 for no forcing, versus >0 for forcing experiments as detailed above) |
Example File Names:BPA1_A_D2_T3_E10_GZ3p.nc
NNNn_X_Dd_Tt_Ee_GZ3p.nc
Refer to Table 4 for the valid values for the file name variables listed above.
Variable | Description |
---|---|
NNN | three letter characters for name, either a group name like PSU for Penn State, or an individual name made up by the first character of the first name followed by the first two characters of the last name |
n | model number (n = 1 if you have only one model) |
X | experiment category, either A for Antarctica, or G for Greenland |
D | denotes model dimension |
d | model dimension identifier (1 for 1D, 2 for 2D, 3 for 3D) |
T | denotes combinations of climate, sliding, and/or ocean treatments |
t | multiple forcing identifier (1 for climate, sliding, and ocean, 2 for climate and sliding, and 3 for climate and ocean forcings with experiment number (see below), e assigned with the following amplification factors if that particular forcing is included 9_GZ3p = effectively plastic (m =8) substrate across entire domain following forcing of linear viscous (m = 1) 6_GZ3 10_GZ3p = 9_GZ3p with an ~11% reduction in upstream flux) |
E | denotes experiment category |
e | experiment number (0 for no forcing, versus >0 for forcing experiments as detailed above) |
Refer to Table 5 for the names and descriptions of the files in the data set.
File Name | Approximate File Size | Description |
---|---|---|
BPA1_A_D2_C1_E0.nc | 2.7 MB | Constant-climate control run; fixed at 2004 values |
BPA1_A_D2_C2_E1.nc | 2.7 MB | Climate forcing of 1x the anomalies from ensemble mean of 18 AR4 climate models for the A1B emissions scenario |
BPA1_A_D2_C2_E2.nc | 2.7 MB | Climate forcing of 1.5x the anomalies from ensemble mean of 18 AR4 climate models for the A1B emissions scenario |
BPA1_A_D2_C2_E3.nc | 2.7 MB | Climate forcing of 2x the anomalies from ensemble mean of 18 AR4 climate models for the A1B emissions scenario |
BPA1_A_D2_S1_E1.nc | 2.7 MB | Sliding forcing with 2x amplification factor on u(b) |
BPA1_A_D2_S1_E2.nc | 2.7 MB | Sliding forcing with 2.5x amplification factor on u(b) |
BPA1_A_D2_S1_E3.nc | 2.7 MB | Sliding forcing with 3x amplification factor on u(b) |
BPA1_A_D2_M1_E1.nc | 2.7 MB | Ocean forcing with subshelf melt rates of 2 m/yr |
BPA1_A_D2_M1_E2.nc | 2.7 MB | Ocean forcing with subshelf melt rates of 20 m/yr |
BPA1_A_D2_M1_E3.nc | 2.7 MB | Ocean forcing with subshelf melt rates of 200 m/yr |
BPA1_A_D2_M1_E4.nc | 2.7 MB | Ocean forcing with subshelf melt rates from coupled ocean-ice models |
BPA1_A_D2_T1_E2.nc | 2.7 MB | C1S1M4 combination forcings. See above for the surface, bed, and ocean components included here. |
BPA1_A_D2_T2_E1.nc | 2.7 MB | C1S1 combination forcings. See above for the surface, bed, and ocean components included here. |
BPA1_A_D2_T3_E1.nc | 2.7 MB | C1M1 combination forcings. See above for the surface, bed, and ocean components included here. |
BPA1_A_D2_T3_E2.nc | 2.7 MB | C1M4 combination forcings. See above for the surface, bed, and ocean components included here. |
BPA1_A_D2_T3_E3_T1.nc | 2.7 MB | T1=C1M4 above with higher resolution topographic data around the grounding zone and activation of ocean coupling for entire simulation |
BPA1_A_D2_T3_E4_GZ1.nc | 2.7 MB | T1 with enhanced basal melting and reduced friction within a 5 km grounding zone. |
BPA1_A_D2_T3_E5_GZ2.nc | 2.7 MB | T1 with enhanced basal melting and reduced friction within a 6 km grounding zone. |
BPA1_A_D2_T3_E6_GZ3.nc | 2.7 MB | T1 with enhanced basal melting and reduced friction within a 7 km grounding zone. |
BPA1_A_D2_T3_E7_GZ4.nc | 2.7 MB | T1 with enhanced basal melting and reduced friction within a 10 km grounding zone. |
BPA1_A_D2_T3_E8_GZ5.nc | 2.7 MB | T1 with enhanced basal melting and reduced friction within a 6 km grounding zone and the lower resolution SeaRISE basal topography. |
BPA1_A_D2_T3_E9_GZ3p.nc | 2.7 MB | Effectively plastic (m = 8) substrate across entire domain following forcing of linear viscous (m = 1) GZ3 run |
BPA1_A_D2_T3_E10_GZ3p.nc | 2.7 MB | GZ3p with an ~11% reduction in upstream flux |
The NetCDF files are approximately 2.7 MB each.
The entire data set is approximately 62 MB.
Spatial coverage is:
Southernmost Latitude: 76.65° S
Northernmost Latitude: 74.05° S
Easternmost Longitude: 105.28° W
Westernmost Longitude: 110.06° W
Spatial Resolution
Spatial resolution varies between 0.1 km to 1 km.
Projection and Grid Description
Refer to Table 6 for the description of the projection and grid structure
Projection and Grid Variables | Value |
---|---|
grid_mapping_name | polar_stereographic |
false_easting | 0 |
false_northing | 0 |
straight_vertical_longitude_from_pole | 0 |
latitude_of_projection_origin | -90 |
standard_parallel | 71 |
This modeling data set covers from 1973 to 2500.
Temporal Resolution
Temporal resolution is either weekly (arrays with a dimension = 27405) or decadal (arrays with a dimension = 54)
Ground Ice
Ice Depth/Thickness
Ice Extent
Ice Temperature
Ice Velocity
Ice Temperature
Glacier Mass Balance
Variable Description
Refer to Table 7 for the output variables descriptions.
Variable Name | Units | Description |
---|---|---|
time | yrs | reported years (at constant decadal intervals) relative to 2004-1-1 0:0:0 (1973-2500) |
tseries | yrs | reported years (at constant weekly intervals) relative to 2004-1-1 0:0:0 (1973-2500) |
x | m | projection_x_coordinate (2D horizontal variables are 1D (with an associated flowband width); (x,y) coordinates for 1D nodes spaced at 5 km are recorded in the x and y variables) |
y | m | projection_y_coordinate (2D horizontal variables are 1D (with an associated flowband width); (x,y) coordinates for 1D nodes spaced at 5 km are recorded in the x and y variables) |
lat | ° | latitude |
lon | ° | longitude |
x_flowline | m | distance along flowline with 1-km resolution |
ivol | m3 | ice volume (ice equiv.) |
totig | m3 | grounded ice volume (ice equiv.) |
totif | m3 | floating ice volume (ice equiv.) |
iarea | m2 | area covered by ice |
iareag | m2 | area covered by grounded ice |
iareaf | m2 | area covered by floating ice |
flowbandwidth | m | flowband width along the flowline (at x_flowline) |
usruf | m | surface topography or elevation |
topg | m | bedrock topography or elevation (Note: elevation of ice bottom = usurf - thk = topg for grounded ice) |
thk | m | ice thickness |
acab | m/yr | upper surface mass balance (ice equiv.) |
bmelt | m/yr | lower surface mass balance (ice equiv.) |
dHdt | m/yr | tendency of ice thickness (ice equiv.) |
mask | NA | Integer mask: flag_values = 1 ice-free ocean, 2 ice-free land, 3 grounded ice, 4 floating ice |
gline_flux | m2/yr | grounding line flux (ice equiv.) |
uvelsurf | m/yr | flowline ice velocity at the surface |
uvelbase | m/yr | flowline ice velocity at the base |
tempsurf | K | ice temperature at the surface |
Software and Tools
In order to view the data, download the free software Panoply netCDF, HDF and GRIB Data Viewer from NASA.
Data Acquisition and Processing
References and Related Publications
Contacts and Acknowledgments
Byron R. Parizek
Penn State DuBois
Mathematics and Geosciences
181 Smeal Building
College Place
DuBois, PA 15801
USA
Don Blankenship
Institute for Geophysics
J.J. Pickle Research Campus
Bldg. 196 10100 Burnet Rd.
Austin, TX 78758
USA
Todd K. Dupont
University of California
Department of Earth System Science
3218 Croul Hall
Mail Code 3100
Irvine, CA 92697
USA
John W. Holt
Institute for Geophysics
University of Texas at Austin
4412 Spicewood Springs Rd. #600
Austin, TX 78759-8500
USA
This research was supported by NSF OPP grant numbers 0531211, 0632198, 0732844, 0758274, 0909335. Other grants supporting the research were the Center for Remote Sensing of Ice Sheets (CReSIS) grant number 0424589, NASA grant numbers NRA-04-OES-02, NNX-09-AV94G, NNX-10-AI04G, 10-CRYO10-0025, and the NASA Cryospheric Science program grant number 281945.02.53.02.19.
Document Information
Document Creation Date
October 2014
Access complete Knowledge Base
Questions? Please contact:NSIDC User Services
Phone: 1 303 492-6199
Email: nsidc@nsidc.org