GRIB2 - PRODUCT DEFINITION TEMPLATE 4.97

Average, accumulation, extreme values or other statistically processed values of post-processing analysis or forecast
at a horizontal level or in a horizontal layer at a local time

Created 08/23/2023


Octet No. Contents
10
Parameter category (see Code table 4.1)
11
Parameter number (see Code table 4.2)
12-13
Input process identifier (see Note 1)
14-15
Input originating center (see Note 2 and Common Code table C-11)
16
Type of post-processing (see Note 3)
17
Type of generating process (see Code table 4.3)
18
Background generating process identifier (defined by originating center)
19
Analysis or forecast generating process identifier (defined by originating center)
20
Type of first fixed surfaced (see Code table 4.5)
21
Scale factor of first fixed surface
22-25
Scaled value of first fixed surface
26
Type of second fixed surfaced (see Code table 4.5)
27
Scale factor of second fixed surface
28-31
Scaled value of second fixed surface
32
Statistical process used to calculate the fields that will be used in the local time processing (see Code Table 4.10)
33
Indicator of unit of time range over which statistical processing is done (see Code Table 4.4)
34-37
Length of the time range over which statistical processing is done in units defined by the previous octet (see Note 4)
38
Number of statistically processed fields used in the local time composite field (see Note 5)
39
Method used to derive the data field values at the local time specified in section 1 (see Code Table 4.248)
40
n - number of forecasts used to create the composite data field at the local time specified in section 1 (n >= 1) (see Note 6)

Octets 41-58 Specification of the analysis or forecast used in the processing (n=1)
41-42
Year of the analysis or forecast used in the processing
43
Month of the analysis or forecast used in the processing
44
Day of the analysis or forecast used in the processing
45
Hour of the analysis or forecast used in the processing
46
Minute of the analysis or forecast used in the processing
47
Second of the analysis or forecast used in the processing
48
Indicator of units of forecast time (see Code Table 4.4)
49-52
Forecast Time (see Notes 7 and 9)
53
Number of time increments of the forecast used in the processing
54
Indicator of units of time for the time increments (see Code Table 4.4)
55-58
Time increments between successive forecast times (see Notes 8)

Octets 59-nn are included only if n > 1 where nn = 40 + 18 x n
52-nn
(n-1) repetitions of sequence of octets 41-58 describing the next analyses or forecasts used in the processing


Notes:

(1) The input process identifier shall have the value of the ""analysis or forecast process identifier"" of the original GRIB message used as input of the post-processing.

(2) The input originating center shall have the value of the ""originating center"" of the original GRIB message used as input of the post-processing.

(3) This identifies which post-processing technique was used. This is defined by the originating center.

(4) This represents the length of time over which the statistical processing was applied. The local time defined in section 1 represents the end of this processing.
For instance, a value of 24 h corresponds to a statistical processing between the previous day at local time and this day at local time.

(5) This represents the number of statistically processed fields (or stripes) used to create the composite local time field. For instance, a value of 8 means
that 8 statistically processed fields have been used in the processing, each of them representing a section of 45 degrees of longitude (360/8) centerd
around the UTC time corresponding to the local time.

(6) This is the number of forecasts and time steps used to create the statistically processed fields. These implicitly have the same statistical process as defined
in octet 32. If a forecast has 2 time increments (3 hourly day 1 to 5 then 6 hourly), it should be encoded as 2 forecasts with the same reference time, using
the appropriate starting forecast time and time increments.

(7) The reference time in octets 41-47 and the forecast time together define the beginning of the overall time interval

(8) This also represents the length of time range of the statistically processed fields. For instance, to create a 24 h accumulation (encoded in octets 34-37), we
could use several 3 h accumulations, or 6 h accumulations, a mixture of the two, etc.

(9) Set code to missing if analysis.


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