GRIB2 - PRODUCT DEFINITION TEMPLATE 4.142

Individual ensemble reforecast, control and perturbed, at a horizontal level or in a horizontal layer at a point in time
for wave 2D spectra with explicit list of frequencies and directions

Created 09/29/2025


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 centre)
22
 Analysis or forecast generating process identifier (see ON388 Table A)
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 octet 26
31
 Type of ensemble forecast (see Code table 4.6)
32-35
 Perturbation number
36-39
 Number of forecasts in ensemble
40-41
 Year of model version date
42
 Month of model version date
43
 Day of model version date
44
 Hour of model version date
45
 Minute of model version date
46
 Second of model version date
47
 Scale factor of wave directions

The following entry of 4 octets is repeated ND times (ND is defined in octets 14-15)
(48 + (ND-1)*4) - (51 + (ND-1)*4)
 Scaled values of wave directions (see Note 2)
52+(ND-1)*4
 Scale factor of wave frequencies

The following entry of 4 octets is repeated NF times (NF is defined in octets 18-19)
(53 + (ND-1)*4 + (NF-1)*4) - (56 + (ND-1)*4 + (NF-1)*4)
 Scaled values of wave frequencies (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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