File Name Convention
--------------------
The filenames for the White and Black Sky Albedo files use the following naming 
convention:

avhrr_BSA:  Black_Sky_Albedo (unitless)
avhrr_WSA:  White_Sky_Albedo (unitless)
vis: Albedo for Visible broadband (350-680nm)
swir: Albedo for Shortwave Infrared broadband (680-3000nm) 
brd: Albedo for Solar broadband (350-3000nm)
1d: 1 degree resolution
hd: half degree resolution
qd: quarter degree resolution
1995mm: Where 1995 is year, mm is the month (either February or July).

So the file "avhrr_BSAbrd_hd_199502.asc" is the Black Sky broadband solar 
Albedo for February 1995 at 1/2 degree resolution. 


The filenames for the AVHRR BRDF model parameters use the following naming 
convention:
 
avhrr_BRDF: BRDF model parameters (unitless)
vis: BRDF model parameters for Visible broadband (350-680nm)
swir: BRDF model parameters for Shortwave Infrared broadband (680-3000nm) 
brd: BRDF model parameters for Solar broadband (350-3000nm)
c1: Isotropic BRDF model parameter (see Strugnell et al. 2001).
c2: Volumetric BRDF model parameter (see Strugnell et al. 2001).
c3: Geometric BRDF model parameter (see Strugnell et al. 2001).
1d: 1 degree resolution
hd: half degree resolution
qd: quarter degree resolution
1995mm: Where 1995 is year, mm is the month (either February or July).

So the file "avhrr_BRDFswir_c2_1d_199507.asc" is the Volumetric BRDF model 
parameter for the Shortwave Infrared broadband for July 1995 at 1 degree 
resolution.

The files that have an extension of *.dif" are ASCII tables of "differences", 
or points in the original file that did not match the ISLSCP II Land/Sea mask, 
and were removed from the ASCII map files.

ASCII File Format
------------------
All of the files in the ISLSCP Initiative II data collection are in the standard 
ARCGIS ASCII GRID, or text format. The file format consists of numerical fields 
of varying length, which are delimited by a single space and arranged in columns 
and rows. The files at different spatial resolutions each contain the following 
numbers of column and rows:
   One degree: 360 columns by 180 rows 
   1/2 degree: 720 columns by 360 rows 
   1/4 degree: 1440 columns by 720 rows 

All values are written as floating point values. Missing values are assigned the 
value of -99 on all data layers. Missing values over land are assigned the value 
of -88.

All files are gridded to a common equal-angle lat/long grid, where the 
coordinates of the upper left corner of the files are located at 180W, 90N and 
the lower right corner coordinates are located at 180E, 90S. Data in the files 
are ordered from North to South and from West to East beginning at 180 degrees 
West and 90 degrees North.

The ASCII map files (with the extension of ".asc") have all had the ISLSCP II 
land/water mask applied to them. All points removed from the original files are 
stored in "differences" files (with the extension ".dif"). These ASCII files 
contain the Latitude and Longitude location of the cell-center of each removed 
point, and the data value at that point. There is one ".dif" file for each ASCII 
map file.