GRIB2 - PRODUCT DEFINITION TEMPLATE 4.42

Average, Accumulation, and/or Extreme values or Other statistically-processed
values at a horizontal level or in a horizontal layer in a continuous or
non-continuous time interval for atmospheric chemical constituents

Created 05/27/2009


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
 Analysis or forecast generating process identified (see Code ON388 Table A)
17-18
 Hours after reference time data cutoff (see Note 1)
19
 Minutes after reference time data cutoff
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 surfaced (see Code Table 4.5)
32
 Scale factor of second fixed surface
33-36
 Scaled value of second fixed surfaces
37-38
 Year  ― Time of end of overall time interval
39
 Month  ― Time of end of overall time interval
40
 Day  ― Time of end of overall time interval
41
 Hour  ― Time of end of overall time interval
42
 Minute  ― Time of end of overall time interval
43
 Second  ― Time of end of overall time interval
44
 n ― number of time ranges specifications describing the time intervals used to calculate the statistically-processed field
45-48
 Total number of data values missing in 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 the result of continuous (or near continuous) process, not the of a number of discrete samples. Examples of such continuous process are the temperatures measured by analogue maximum and minimum thermometers or thermographs and the rainfall measured by a rain gauge.

(4)   The reference and forecast times are successively set to their initial 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 reference and forecast time.


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