Format for 48 km
containing daily Northern Hemisphere snow-depth and ice coverage
Each data file contains two identical 20-byte header records in the form of a 16-byte character string of the form ‘NHSNOW ddmmyy ‘ (where dd is the day of the month, mm is the first two characters in the month name, and yy is the two digit year), followed by an INTEGER*4 value representing the number of hours since December 31, 1967.
The data are presented on a Polar Stereographic
512 x 512
array, laid out such that point (1,1) starts
lower left corner. The top of the file
is South America, the left side is the Pacific Ocean, the right side is
and the bottom is
Each row (i) of the array is a data record consisting of 512 INTEGER*2 values [representing the 512 columns (j) in the row]. The first data record holds values in row 512. The second data record holds values in row 511, etc. The 512’th (and last) data record holds values in row 1. Data values in the files range from 0 to 4090. A value of 4090 is the sea ice flag. Otherwise, the value represents inches of snow*10. (e.g. 250 means 25.0 inches of snow).
Points in the
The 512 x 512 Polar Stereographic grid has a mesh length of 47.625 km at 60 degrees N latitude and is oriented at 80 degrees W longitude. The coordinates of the North Pole are (257, 256). Grid point (1,1) is at 20.721 S latitude, 125.112 W longitude.