GRIB2 - PRODUCT DEFINITION TEMPLATE 4.153

Individual large ensemble reforecast, control and perturbed, at a horizontal level or in a horizontal layer,
in a continuous or non-continuous time interval for atmospheric chemical constituents

Created 11/19/2025


Octet No. Contents
10
Parameter category (see Code table 4.1)
11
Parameter number (see Code table 4.2)
12-13
Atmospheric chemical constituent type (see Code table 4.230)
14
Type of generating process (see Code table 4.3)
15
Background generating process identifier (defined by originating centre)
16
Forecast generating process identifier (see ON388 Table A)
17-18
Hours after reference time of data cut-off (see Note 1)
19
Minutes after reference time of data cut-off
20
Indicator of unit of time range (see Code table 4.4)
21-24
Forecast time in units defined by octet 20 (see Note 2)
25
Type of first fixed surface (see Code table 4.5)
26
Scale factor of first fixed surface
27-30
Scaled value of first fixed surface
31
Type of second fixed surface (see Code table 4.5)
32
Scale factor of second fixed surface
33-36
Scaled value of second fixed surface
37
Type of ensemble forecast (see Code table 4.6)
38-41
Perturbation number
42-45
Number of forecasts in ensemble
46-47
Year of model version date (see Note 3)
48
Month of model version date
49
Day of model version date
50
Hour of model version date
51
Minute of model version date
52
Second of model version date
53-54
Year of end of overall time interval
55
Month of end of overall time interval
56
Day of end of overall time interval
57
Hour of end of overall time interval
58
Minute of end of overall time interval
59
Second of end of overall time interval
60
n - number of time range specifications describing the time intervals used to calculate the statistically processed field
61-64
Total number of data values missing in statistical process

65-76 Specification of the outermost (or only) time range over which statistical processing is done
65
Statistical process used to calculate the processed field from the field at each time increment during the time range
(see Code table 4.10)
66
Type of time increment between successive fields used in the statistical processing (see Code table 4.11)
67
Indicator of unit of time for time range over which statistical processing is done (see Code table 4.4)
68-71
Length of the time range over which statistical processing is done, in units defined by octet 67
72
Indicator of unit of time for the increment between the successive fields used (see Code table 4.4)
73-76
Time increment between successive fields, in units defined by octet 72 (see Notes 4 and 5)

77-nn These octets are included only if n > 1, where nn = 64 + 12 x n
77-88
As octets 65 to 76, next innermost step of processing
89-nn
Additional time range specifications, included in accordance with the value of n.
Contents as octets 65 to 76, repeated as necessary


Notes:

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

(2)  The reference time in section 1 and the forecast time together define the beginning of the overall time interval.

(3)  This is the date when the reforecast is produced with a particular version of the model.

(4)  An increment of zero means that the statistical processing is the result of a continuous (or near-continuous) process, not the processing of a number of discrete samples. Examples of such continuous processes are the temperatures measured by analogue maximum and minimum thermometers or thermographs, and the rainfall measured by a rain gauge.

(5)  The reference and forecast times are successively set to their initial values plus or minus the increment, as defined by the type of time increment (one of octets 51, 63, 75, ...). For all but the innermost (last) time range, the next inner range is then processed using these reference and forecast times as the initial reference and forecast times.


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