BOREAS Follow-on DSP-10 Regridded NDVI Maps for 1994, 10 by 5 minutes
---------------------------------------------------------------------
 March 2, 2001

These images were produced by averaging the 1-km FASIR-NDVI maps by Jing 
Chen to a 10' (horizontal) by 5' (vertical) pixel size in a straight 
latitude/longitude grid.  Each pixel represents the average NDVI of the
1-km pixels that fall in each 10' by 5' pixel, where more than 50% of the 1-km
pixels in the 10' by 5' area are not cloud and are not missing.  If more than
50% of the 1-km pixels are missing or cloudy, a value of 0 is assigned to the
10' by 5' pixel.

See document "rss_staff_avhrr_l4c_doc.html" for more information on the
original data product that this is based on.

If there are any questions about how this aggregation was done, please
contact Dave Knapp (David.Knapp@gsfc.nasa.gov).


Image Specifications
--------------------
The following images represent the average FASIR-NVDI (unsmoothed) for the 
following 10-day compositing periods.

94-04-11_ndvi.img  (April 11-21, 1994)
94-04-21_ndvi.img  (April 21-31, 1994)
94-05-01_ndvi.img  (May 1-10, 1994)
94-05-11_ndvi.img  (May 11-20, 1994)
94-05-21_ndvi.img  (May 21-31, 1994)
94-06-01_ndvi.img  (June 1-10, 1994)
94-06-11_ndvi.img  (June 11-20, 1994)
94-06-21_ndvi.img  (June 21-31, 1994)
94-07-01_ndvi.img  (July 1-10, 1994)
94-07-11_ndvi.img  (July 11-20, 1994)
94-07-21_ndvi.img  (July 21-31, 1994)
94-08-01_ndvi.img  (Aug 1-10, 1994)
94-08-11_ndvi.img  (Aug 11-20, 1994)
94-08-21_ndvi.img  (Aug 21-31, 1994)
94-09-01_ndvi.img  (Sep 1-10, 1994)

Each image is 66 pixels by 60 lines and contains no leading header bytes.
Each pixel in the image is represented by two bytes.  Byte swapping may
be necessary to use the data on your system.  If the data appear to be
out of the range 0 to 20000, Use the following UNIX command to swap the
bytes:

dd if=in_file conv=swab of=out_file

The DN for each pixel can be converted to NDVI with the following equation:

NDVI = (DN/10000) - 1


The Pixel-Area Image
--------------------
The file "0_pixel_area_10by5min.img" is an image that provides the area for each 
of the 10 by 5 minute cells. The area for each pixel is given in hectares.
One hectare equals 10,000 square meters. 

Each pixel value is represented as a 2-byte integer.  This image has 
the low-order byte first.  On some systems, the bytes may need to be 
swapped in order the read the 2-byte integers correctly.  On UNIX 
systems, this can be done with the following command.

dd if=input_file_name conv=swab of=output_file_name 


Spatial Coverage
----------------
These data cover the same area as the regional meteorological parameters 
assembled by Val Pauwels.  The data are in a straight latitude/longitude
grid.  The BOREAS grid coordinates listed below are simply given for 
reference purposes.  The corner coordinates are identical to the upper left 
corner of Val's regional data set.

Corner          X         Y        Longitude         Latitude
--------------------------------------------------------------------------
Upper Left    242.697   675.191  107¡00'00.00" W   57¡00'00.00" N
Upper Right   903.583   765.939   96¡00'00.00" W   57¡00'00.00" N
Lower Left    274.686   119.043  107¡00'00.00" W   52¡00'00.00" N
Lower Right  1022.683   221.752   96¡00'00.00" W   52¡00'00.00" N

The X and Y coordinates are the BOREAS grid coordinates which are based on
an Albers Equal Area Conic (AEAC) projection with the following parameters:

Origin: 111.00 deg W, 51.00 deg N
Standard Parallels: 52.5 deg N
                    58.5 deg N
Units of Measure: kilometers