GRIB2 - GRID TEMPLATE 4.12
Derived forecasts based on all ensemble members at a horizontal level or in a horizontal layer in a continuous or non-continuous time interval
Created 08/29/2005

Octet | Contents
--- | ---
10 | Parameter category (see Code Table 4.1)
11 | Parameter number (see Code Table 4.2)
12 | Type of generating process (see Code Table 4.3)
13 | Background generating process identifier (defined by originating Centre)
14 | Forecast generating process identifier (defined by originating Centre)
15-16 | Hours after reference time data cutoff (see Note 1)
17 | Minutes after reference time data cutoff
18 | Indicator of unit of time range (see Code Table 4.4)
19-22 | Forecast time in units defined by octet 18 (see Note 2)
23 | Type of first fixed surface (see Code Table 4.5)
24 | Scale factor of first fixed surface
25-28 | Scaled value of first fixed surface
29 | Type of second fixed surfaced (see Code Table 4.5)
30 | Scale factor of second fixed surface
31-34 | Scaled value of second fixed surfaces
35 | Derived forecast (see Code Table 4.7)
36 | Number of forecasts in the ensemble (N)
37-38 | Year of end of overall time interval
39 | Month of end of overall time interval
40 | Day of end of overall time overall time interval
41 | Hour of end of overall time interval
42 | Minute of end overall time interval
43 | Second of end of overall time interval
44 | n ― number of time range specifications describing the time intervals used to calculate the statistically-processed field
45-48 | Total number of data values missing in the statistical process 49-60 Specification of the outermost (or only) time range over which statistical processing is done
49 | Statistical process used to calculate the processed field from the field at each time increment during the time range (see Code Table 4.10)
50 | Type of time increment between successive fields used in the statistical processing (see Code Table 4.11)
51 | Indicator of unit of time for time range over which statistical processing is done (see Code Table 4.4)
52-55 | Length of the time range over which statistical processing is done, in units defined by the previous octet
56 | Indicator of unit of time for the increment between the successive fields used (see Code Table 4.4)
57-60 | Time increment between successive fields, in units defined by the previous octet (see Notes 3 and 4) 61-nn These octets are included only if n>1, where nn = 48 +12 x n
61-72 | As octets 49 to 60, next innermost step of processing
73-nn | Additional time range specifications, included in accordance with the value of n, Contents as octets 49 to 60, 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) 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 guage. (4) 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 50, 62, 74 ...). For all but the innermost (last) time range, the next inner range is then processed using these reference and forecast times as the initial references and forecast time.

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