GRIB2 - PRODUCT DEFINITION TEMPLATE 4.101

Analysis or forecast at a horizontal level or in a horizontal layer at a point in time for wave 2D spectra with
frequencies and directions defined by formulae

Created 08/30/2023


Octet No. Contents
10
Parameter category (see Code table 4.1)
11
Parameter number (see Code table 4.2)
12-13
Wave direction number
14-15
Number of wave directions (ND)
16-17
Wave frequency number
18-19
Number of wave frequencies (NF)
20
Type of generating process (see Code table 4.3)
21
Background generating process identifier (defined by originating center)
22
Analysis or forecast generating process identifier (defined by originating center)
23-24
Hours of observational data cut-off after reference time (see Note 1)
25
Minutes of observational data cut-off after reference time
26
Indicator of unit of time range (see Code Table 4.4)
27-30
Forecast time in units defined by previous octet
31
Type of wave direction sequence
32
Number of wave direction sequence parameters (NDSP)

The next two entries are repeated NDSP times to encode the scale factors and scaled values of the sequence parameters.
33 + (NDSP-1)*5
Scaled factor of wave direction sequence parameter
34+(NDSP-1)*5 - 37+(NDSP-1)*5
Scaled value of wave direction sequence parameter (see Note 2)
33+NDSP*5
Type of wave frequency sequence (see Code Table 4.251)
34+NDSP*5
Number of wave frequency sequence parameters (NFSP)

The next two entries are repeated NFSP times to encode the scale factors and scaled values of the sequence parameters
35+NDSP*5+(NFSP-1)*5
Scale factor of wave frequency sequence parameter
36+NDSP*5+(NFSP-1)*5 -39+NDSP*5+(NFSP-1)*5
Scaled value of wave frequency sequence parameter (see Note 3)


Notes:

(1) Hours greater than 65534 will be coded as 65534.

(2) The units of the wave directions are degree true.

(3) The frequencies are defined as 1/T where T is the wave period in seconds.



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