IMAPP MODIS Direct Broadcast Ice Surface
    Temperature (IST) Product Description
  -------------------------------------------

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  The IMAPP IST software produces retrievals of surface temperature
  over ice covered surfaces and surrounding waters from MODIS 1 km 
  resolution L1B files and the MODIS 1 km Cloud Mask file. The software 
  was developed by Dr. Jeffrey Key, NOAA/NESDIS and integrated into 
  IMAPP by Kathleen Strabala, kathy.strabala@ssec.wisc.edu.

  For a description of the algorithm, please see:

  Hall, D.K., J. Key, K.A. Casey, G.A. Riggs, and D.J. Cavalieri, 
    2004, Sea ice surface temperature product from the Moderate 
    Resolution Imaging Spectroradiometer (MODIS), IEEE Trans. 
    Geosci. Remote Sensing, 42(5), 1076-1087.

  Key, J., J. Collins, C. Fowler, and R. Stone, 1997. High-latitude 
    surface temperature estimates from thermal satellite data. Remote 
    Sensing Environ., 61, 302-309.

  Output for this product is a flat binary file and an HDF4 file.

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Binary Output File
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  The *.ist.bin file consists of one band containing 2 byte integer values
  scaled by 0.1 at 1 km resolution in degrees K.  The size of the file 
  will depend upon the size of the pass that is being processed 
  (1354 x number_of_lines x 2 bytes).

   Example file name:  a1.11012.0430.ist.bin
   Two byte integers
   Scale factor:  0.1
   1 parameter  -  Ice Surface Temperatures in Degrees K
   1 km pixel resolution

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HDF4 OUTPUT FILE
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  The HDF4 output file (*ist.hdf) contains 3 arrays.  Latitude, Longitude, 
  and the Ice Surface Temperature in degrees K at 1 km resolution. 
  The Ice Surface Temperature array is stored as 2 Byte Integers, and can be 
  converted to the actual temperature by applying the scale factor
  of 0.1. 

  The Latitude and Longitude arrays are stored as 4 byte float values
  at 5 km resolution.
  
  Example filename:  a1.11012.0430.ist.hdf


 (Example ncdump -h of an IMAPP IST HDF file)

netcdf a1.11012.0430.ist.hdf {
dimensions:
        Cell_Along_Swath_5km = 406 ; (example)
        Cell_Across_Swath_5km = 271 ;
        Cell_Along_Swath_1km = 2030 ; (example)
        Cell_Across_Swath_1km = 1354 ;

variables:
        float Latitude(Cell_Along_Swath_5km, Cell_Across_Swath_5km) ;
                Latitude:_FillValue = -999.98999f ;
        float Longitude(Cell_Along_Swath_5km, Cell_Across_Swath_5km) ;
                Longitude:_FillValue = -999.98999f ;
        short Ice_Surface_Temperature(Cell_Along_Swath_1km,Cell_Across_Swath_1k
m) ;
                Ice_Surface_Temperature:units = "K" ;
                Ice_Surface_Temperature:scale_factor = 0.1 ;
                Ice_Surface_Temperature:add_offset = 0. ;
                Ice_Surface_Temperature:valid_range = 3000s, 1800s ;
                Ice_Surface_Temperature:_FillValue = -10s ;
}