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Time Dependent Topography Through the Glacial Cycle

Frequently-anticipated questions:

• What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How should this data set be cited?

   Peltier, W.R., 1993, Time Dependent Topography Through the Glacial Cycle: IGBP PAGES/World Data Center-A for Paleoclimatology Data Contribution Series 93-015, NOAA/NGDC Paleoclimatology Program, Boulder CO, USA..

   Online Links:

   • <ftp://ftp.ngdc.noaa.gov/paleo/ice_topo/>

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -180.0

   East_Bounding_Coordinate: 180.0

   North_Bounding_Coordinate: 90.0

   South_Bounding_Coordinate: -90.0

3. What does it look like?

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: cc21000

   Ending_Date: present

   Currentness_Reference:

   ground condition; data are given in 1000-year steps from 21ka to present

5. What is the general form of this data set?

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?

      This is a Raster data set. It contains the following raster data types:

      • Dimensions 180 x 360 x 22, type Pixel

   2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 1. Longitudes are given to the nearest 1. Latitude and longitude values are specified in Decimal degrees.

7. How does the data set describe geographic features?

   Topography grid cell

   16-bit value at even offsets in topography files (Source: Peltier, 1994)

   Topography grid cell value

   Topographical heights at 1 Kyr intervals since the last glacial maximum, plus 10000 (Source: Peltier, 1994)

   Range of values
   Minimum:	700
   Maximum:	17200
   Units:	meters
   Resolution:	1

   Ice cover grid cell

   16-bit value at even offsets in ice cover files (Source: Peltier, 1994)

   Ice cover grid cell value

   Overall presence of ice in the grid cell (Source: Peltier, 1994)

   Value	Definition
   0	Grid cell not ice-covered
   1	Grid cell is ice-covered

   Range of values
   Units:	logical
   Resolution:	1

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Peltier, W.R.

2. Who also contributed to the data set?

3. To whom should users address questions about the data?
   Peltier, W.R.
   Department of Physics, University of Toronto
   Department of Physics
   University of Toronto
   Toronto, ON Canada
   

   unavailable (voice)
   

Why was the data set created?

Presentation of results of model ICE4G.

How was the data set created?

1. From what previous works were the data drawn?

   Peltier, 1994 (source 1 of 1)

   Peltier, W.R., 1994, Ice age paleotopography: Science v. 265, pp. 195-201.

   Type_of_Source_Media: paper

   Source_Contribution:

   This published paper describes the mathematical model used to create the data set.

2. How were the data generated, processed, and modified?

   Date: 1993 (process 1 of 1)

   Compilation of data set is described in Peltier, 1994.

   Data sources used in this process:

   • Peltier, 1994

3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?

   See source information

2. How accurate are the geographic locations?

   see source information

3. How accurate are the heights or depths?

4. Where are the gaps in the data? What is missing?

   See source information

5. How consistent are the relationships among the observations, including topology?

   See source information

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: none

Use_Constraints: none

1. Who distributes the data set? (Distributor 1 of 1)
   National Geophysical Data Center
   c/o Bruce Bauer
   325 Broadway E/GCx3
   Boulder, CO 80303
   USA
   

   303-497-6280 (voice)
   303-497-6513 (FAX)
   bab@ngdc.noaa.gov
   

2. What's the catalog number I need to order this data set?

   paleo/ice_topo

3. What legal disclaimers am I supposed to read?

   unknown

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	The data files are at 1,000 year intervals, for example Top18.asc is the 18,000YBP Topography data file. in format BIL (version 0) 16 bit binary unsigned integers, least significant byte first Size: 3MB
     Network links:	<ftp://ftp.ngdc.noaa.gov/paleo/ice_topo/ice.tar.Z> <ftp://ftp.ngdc.noaa.gov/paleo/ice_topo/top.tar> <ftp://ftp.ngdc.noaa.gov/paleo/ice_topo/readme_ice_topography.txt>

   • Cost to order the data: none

Who wrote the metadata?

Dates:

Last modified: 30-Sep-1998

Metadata author:

Peter N. Schweitzer
U.S. Geological Survey
Mail Stop 918, National Center
12201 Sunrise Valley Drive
Reston, VA 20192

703-648-6533 (voice)
703-648-6560 (FAX)
pschweitzer@usgs.gov

Metadata standard:

Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)