Fields

The text fields which make up a file name are

quantity

A four-character alphanumeric field which begins the file name and and indicates what physical quantity the file contains. This field must start with an alphabetic character.

date

Indicates the date for which the data are valid. The leading character will be I (for instantaneous data), D (indicating data averaged over days), M (indicating data averaged over months), or Y (indicating data averaged over years). If the rest of the field is numeric, then it may be of the form 'yymmdd' or 'yymmddhh', where the y's stand for year digits, the m's for month number digits, d's for the digits of the day of the month, and h's for the hour of the day. If the part of the date field past the leading character is alphabetic, then it is a three-digit base-26 number (A=0, Z=25) indicating the number of days since 1 January 1970.

time

Indicates the time for which the data are valid. The leading character is T. If the rest of the field is numeric, then it is of the form 'mmmmss', where the m's represent minutes, and the s's represent seconds.

source

Indicates the source of the data. This field is a three-character alphanumeric string designating where the data came from. It goes at the end of the file name (usually as an extension) and has no leading character.

format

Indicates the format or binary representation used in the file. The leading character is X. If there are no more characters in this field, or if only one character, P (indicating that the file contains packed data) follows, then the file uses XDR data formats. Otherwise, the lead character is followed either or both of two subfields: a C followed by either A or E, indicating whether character data is ASCII or EBCDIC; or a B followed by a floating-point format indicator (E for IEEE, V for VAX, I for IBM mainframe, and Y for Cray), a byte-order flag (B for big-endian, L for little-endian), a word-order flag (B for big-endian, L for little-endian), record-header flag (C for C-style stream files without record headers, F for Fortran record headers), a flag indicating the type of file record structure (S for pure stream files, V for variable-length records, and F for fixed-length records), and a packing flag (P for packed data, U for unpacked).

sequence

Indicates some user-specified sequence number or code. The leading character is E.

gridtype

Specifies on what sort of grid regular, rectangularly gridded data is written. The leading character is G, and the characters following should follow some local convention to indicate grid type, location, grid spacing, etc. If needed, decimal points may be represented by Level-2 delimiter characters (see Section B.3.2).

forecast

Indicates, for model forecast data, how far in advance of the data-valid date or time the data were generated. The leading character is F.

special

Is a field to hold any miscellaneous information the user feels should be included in the file name. The leading character is S.