GRIB2 - PRODUCT DEFINITION TEMPLATE 4.59

Individual Ensemble Forecast, Control and Perturbed, at a horizontal level or in
a horizontal layer at a point in time interval for Spatio-Temporal changing tile parameters

Created 07/07/2017



Octet No. Contents
10
 Parameter category (see Code table 4.1)
11
 Parameter number (see Code table 4.2)
12
 Tile Classification (see Code table 4.242)
13
 Total number (NT) of tile/attribute pairs (See Notes 1 and 2)
14
 Number of used spatial tiles (NUT) (See Notes 1 and 2)
15
 Tile index (ITN={1,...,NUT}) (See Note 1)
16
 Number of used tile attributes (NAT) for tile ITN (See Note 1)
17
 Attribute of tile (see Code table 4.241) (A={A(1),...,A(NAT(ITN))}) (See Note 2)
18
 Type of generating process (see Code table 4.3)
19
 Background generating process identifier (defined by originating centre)
20
 Analysis or forecast generating process identifier (see Code ON388 Table A)
21-22
 Hours of observational data cutoff after reference time (see Note 3)
23
 Minutes of observational data cutoff after reference time
24
Indicator of unit of time range (see Code table 4.4)
25-28
 Forecast time in units defined by octet 24
29
 Type of first fixed surface (see Code table 4.5)
30
 Scale factor of first fixed surface
31-34
 Scaled value of first fixed surface
35
 Type of second fixed surfaced (see Code table 4.5)
36
 Scale factor of second fixed surface
37-40
 Scaled value of second fixed surfaces
41 Type of ensemble forecast (see Code table 4.6)
42
 Perturbation number
43
 Number of forecasts in ensemble

Notes:

(1)   The number of used tiles (NUT) is the number of used different spatial tiles, defining the cover structure of point. As each of these tiles has one or more different tile attributes A(NAT(ITN)), where (ITN=1,...,NUT), for example, (unmodified, snow-covered,...), there are NT=∑ITN=1NUT NAT(ITN) fields (that is, the total number of tile attribute pairs, defined in (octet 13) with indices (ITN,IAN) with the following meaning (IAN={1,...,ITN)}):
    1,1                                    First tile - first attribute (e.g. unmodified) attribute
    ...                           ...
    1,NAT(1)                         First tile - NAT of first tile (last, e.g. snow-covered) attribute
    2,1                                    Second tile - first attribute (e.g. unmodified)
    ...                          ...
    2,NAT(2)                         Second tile - NAT of second tile (last, e.g. snow-covered) attribute
    ...                          ...
    ...                          ...
    NUT,1                             NUT tile - first attribute (e.g. unmodified)
    ...                          ...
    NUT,NAT(NUT)          NUT tile - NAT of last attribute (last) attribute


A single tile attribute index (ITN,IAN) with spatial tile index ITN(1,...,NUT) and attribute A(IAN) with (IAN=1,...,NAT(ITN)) is represented in the template. All NT partitions are linked by the normalization formula, which states that the sum of all partions must be equal to normalization term (N=1 for fractions and N = 100 for percentage) on each point of the grid.

The fields "tile class" and "tile fraction" must be provided in order to obtain the tile structure of each grid point. Please note that the field "tile fraction" is time-dependent in the case of defined attribute, whereas the field "tile class" is not affected by attribute (NT=NUT).

(2)   For more informtion, see Part B, GRIB Attachment IV.

(3)   Hours greater than 65534 will be coded as 65534.

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