Some Problems with the Snow Cover
					       Eugenia Kalney

An error in the snow cover:

In preparation for the pre-1973 reanalysis, another error was discovered. The snow cover for the NH was 
obtained from a file of snow cover which starts in 1973 maintained by Don Garrett of CPC. The file 
was in ON84 format and had to be converted to GRIB. The NH snow records were first merged into one 
long file. The index array of the week number for each year was used to drive a do-loop, and a problem 
came is matching the FORTRAN to the file format. The concatenated file had been written as an unblocked 
file (-s unblocked) as required by GrADS.

Our previous experience was almost exclusively with blocked files. So instead of positioning the file at 
the beginning of the proper year, the file position kept pointing at January 1973, and the snow cover 
for 1973 was used also for the period 1974-1994. 1973, 1995 and 1996 have the correct snow cover. 

(more text follows)

For the rest of the text, see

            http://www.cpc.ncep.noaa.gov/products/wesley/ek.snow.html