Time Dependent Topography Through the Glacial Cycle
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Source: Prof W.R. Peltier, Dept of Physics, University of Toronto 

Date:   May 1993

Data resolution:        1 degree latitude/longitude grid
        data starting at (-179.5,+89.5) 
        180 rows of (360 points along a line of constant latitude).

Time Period: 21KBP to the present

Data 1: topographical heights at 1 Kyr intervals since the last glacial
        maximum.

Units:  metres. However in order to present a dataset in positive
        integer format, 10000 has been added.
        i.e if the data in this dataset is called itopog
            then
                true_topog = itopog - 10000
        true_topog has values within the range [-9300,7200] metres.

Data 2: Ice-cover data at 1 Kyr intervals since the last glacial maximum.

Values: 1 if there is ice, 0 otherwise.


Files: Either   tar files TOP.tar and ICE.tar
       Or       top.n     for n=0,1,...,21 and
                is_ice.n  for n=0,1,...,21

      OR   asciispecial format files   ice0.asc   through    ice21.asc,
        located in directory /asciispecial.  Asciispecial files are
        text files suitable for import to plotting programs such as
         Spyglass.   The format includes text headers, a listing of 
         lat-long grid values, and the data points (specify 1 header line
         when loading files into Spyglass).

       There is also an ascii version of top.21 called TOP.21.ascii,
       which can be used to check interpretation of the binary files.

        The tar files were created on an SGI machine, you may need to
        use dd to swap bytes on other machines (eg Suns):
          dd if=TOP.tar conv=swab | tar xvof -


Logical Data Structure: 16 bit binary unsigned integers,
                        least significant byte first.


Note:   In some areas, the ice-cover data indicates that there is ice
        while the topographic height is negative indicating that the
        region is below sealevel. In these cases, it should be assumed
        that the area is ice-covered. Either the region is not inundated
        or the ice is floating.

Reference for the data sets is:
Peltier, W. R., Ice Age Paleotopography, 1994, Science, v. 265, pp. 195-201.