New section 4 templates for advanced surface tiling

[sebvi]

Initial request

Several templates for encoding land surface tiling schemes have been proposed in the past and can be divided into 2 categories:

• The templates 4.53 and 4.54, proposed by ECMWF, to encode the tile fractions/percentage within grid boxes. These templates can only be used for this purpose as highlighted in the accompanying notes of the templates: sum of fractions =1 or sum of percentage = 100.
• The templates 4.55, 4.56, 4.59, 4.62 and 4.63, proposed by DWD, tried to generalise the concept, extending it to allow 2 new features: (i) the fractions of tiles do not need to sum up to 1 (or 100% anymore), i.e. only N "dominating tiles" can be considered, (ii) each tile can be further subdivided by tile coverage attributes that are change in space and time during the course of a model run.

From the annex describing the spatio-temporal changing tiles, it is clear that each grid box contains N fixed number of tiles and that the tile types are different from grid box to grid box: with N=3, one grid box could be ocean/forest/crop and another grid box could be urban/lake/bare-rock. The tiles are labelled 1 to N with tile 1 being the highest fraction, tile 2 the next highest and so on to tile N with the smallest fraction. It implies that tile 1 in one grid box could be for instance "ocean" but it could be "deciduous forest" in another grid box. Hence the data is encoded over a set of GRIB2 messages that need to work together to recover what "tile 1" is in a given grid box: typically one message containing the "tile class" parameter using parameter encoded in discipline 2 category 0 entry 35 (2/0/35), which points to Code Table 4.243 and one message to encode the fraction or percentage using 2/0/36 and 2/0/37 respectively.

These templates have a number of caveats, practical and technical:

• If one wants to access only the fraction of "deciduous forest", one must obtain and read all tile 1 to N "tile class" fields
• To discover the tile number of "deciduous forest" in each grid box , one must obtain and read all tile 1 to N "tile class" fields and then all 1 to N "tile fraction" fields and recombine all of them. This is extremely impractical as "accessing by tile class" is much more common than "accessing by tile number" or "accessing by most dominant tile".
• There is no mechanism that "links" the messages together, for instance a common UUID, in the same way that it is done for the section 3 templates for unstructured grids.

Our use case at ECMWF is that now we now want to encode traditional land surface parameters (2m temperature, 10 metre winds, humidity, you name it...) per specific type of tiles: 2m temp of urban areas, over lake, over ocean. This is very relevant because these parameters can be very different over different land surfaces within a grid box and this is usually a source of apparent error when only the spatial average temperature of the grid box is given. With the existing spatio-temporal tile approach, encoding such parameters is possible but is extremely cumbersome as it can't be encoded in a single GRIB message.

We are therefore proposing a new set of tile templates building on the existing spatio-temporal tile approach, trying to fix the issues listed above:
The type of tiles is no longer a set of separate GRIB messages listing the types by decreasing importance, defined through a tile class parameter. Instead the type of tile is included in the template itself, avoiding the need for the extra set of messages. In this approach, tile 1 is always the same type across all grid boxes, and the same for tile 2 to N.
We are also introducing a unique identifier to easily match parameters belonging to the same tile of the same model run configuration.

To prepare these templates, we have been in contact with several land surface modelling groups from ECMWF (IFS), MeteoFrance/SMHI (surfex model) and DWD (ICON) to make sure the new set of templates would fit all use cases. We are proposing a new table listing land type according to the major land cover surveys defined in existing Code Table 2.242 (which we are also extending). The new code table 4.251 is organised to group land type by surveys and can be extended to accommodate new future surveys. Each survey range is divided in a range for base land types and a range for composed land types. This is usually because land surface models tend to group native cover into major groups. A good example of this is how the various vegetation types can be grouped. Note that the dominant tiles approach can still be used if the tile type is set to 3501 and the parameter 2/0/35 is provided again for the tiles 1 to N.

This proposal might seem complex at first. What it does is in fact relatively simple as it simply injects the following keys in existing templates 4.0, 4.8, 4.1 and 4.11 to produce templates 4.113, 4.114, 4.115 and 4.116 respectively:

Octet	Description
12	Tile Classification (see code table 4.242)
13-14	Type of Tile (see code table 4.251)
15	Number of Used Spatial Tiles
16	Number of Used Tile Attribute Combinations for Type of Tile
17	Number of Used Tile Attributes for Tile Attribute Combination (NUTAFTAC)
	Repeat the following octet for each attribute of tile (n=1,NUTAFTAC)
18 + (n-1)	Attribute of Tile (see code table 4.241)
	end of the repetition
19 + (NUTAFTAC-1)	Total Number of Tile Attribute Combinations
20 + (NUTAFTAC-1)	Tile Index
21 + (NUTAFTAC-1) - 36 + (NUTAFTAC-1)	UUID of Data Group

Octet 12: defines the Land survey used to derive the type of tiles. The surveys are listed in the existing Code Table 4.242 and we are proposing to add 3 more surveys to this table.
Octets 13-14: define the type of tile within a specified survey in octet 12. Code table 4.251 is new. We did not want to reuse Code table 4.243 which contains a subset of Code Table 2.251 because 4.243 is tightly couple to its use with the parameter "tile class", discipline 2, category 0, entry 35. Code Table 4.251 is organised in the following way: entries 1-1000 are for generic tile type not coupled with a particular survey and are meant to be used for inter-comparison. Then each subsequent range of a thousand are assigned to a specific Land survey. Within that each range, the first half is for "base tile type" of that survey while the second half is used for groups of tiles, either because the model does not fully resolved the base tiles and because a model could output parameters averaged over a specific group of tiles. For instance, a model could use the entries 1007-1015 for the various types of forest covers or only use the entry 1503 which is the grouping of all the forest covers.
Octet 15: defines the number of tile types without considering additional attributes, i.e. the number of different value that Octets 13-14 could take in the given setup.
Octet 16: defines the number of combination of type attributes for the type of tile given in Octets 13-14. For instance, if for the tile type "forest" there exit the following combination, "bare forest", "Forest + intercepted snow", "Forest + flooded" and "forest + intercepted snow + flooded", then octet 16 should be set to 4. This implies that 4 separate GRIB message will be provided, one for each combination.
octet 17: defines NUTAFTAC which is the number of attributes specified in the following octet(s) 18 to 18 + NUTAFTAC.
octect(s) 18 to 18 + NUTAFTAC-1: if NUTAFTAC=1, then only octet 18 is used to encode 1 attribute, if NUTAFTAC=2, then octects 18 and 19 are used to encode 2 attributes, etc.
octet 19 + NUTAFTAC-1: sum of all combination of type of tiles with their attributes. For instance if a model uses 2 types of tile and type 1 has octet 16 set to 2 and type 2 has octet 16 set to 3, then this octet should be set to 2+3 = 5
octet 20 + NUTAFTAC-1: this is an index given to identify a particular combination of the previous tile keys. In principle, it ranges between 1 and the value encoded in octet 20+NUTAFTAC-1
octets 21 + (NUTAFTAC-1) - 36 + (NUTAFTAC-1) : 16 octets used to encode a unique identifier that encodes the specific tile configuration. All GRIB message sharing the same UUID are to be interpreted together. This provides a validation that the independent GRIB messages belong to the same run.

Amendment details

ADD new entries in Code Table 4.0

Code	Description
113	Generalised tiles at a horizontal level or horizontal layer at a point in time
114	Average, accumulation, and/or extreme values or other statistically processed values on generalised tiles at a horizontal level or in a horizontal layer in a continuous or non-continuous time interval
115	Individual ensemble forecast, control and perturbed on generalised tiles at a horizontal level or in a horizontal layer at a point in time
116	Individual ensemble forecast, control and perturbed on generalised tiles at a horizontal level or in a horizontal layer in a continuous or non-continuous time interval

ADD new entries in Code Table 4.241

Code	Description
5	With intercepted water
6	With intercepted snow
7	Aggregated
8	Unresolved

ADD new entries in Code Table 4.242

Code	Description
3	Land use classes according to ECOCLIMAP
4	Land use classes according to ECOCLIMAP-SG
5	Land use classes according to USGS EROS Global Land Cover Characterization (GLCC) v2.0 BATS Classification

ADD new template 4.113 - Generalised tiles at a horizontal level or horizontal layer at a point in time

Octet	Description
10	Parameter Category (see code table 4.1)
11	Parameter Number (see code table 4.2)
12	Tile Classification (see code table 4.242)
13-14	Type of Tile (see code table 4.251)
15	Number of Used Spatial Tiles
16	Number of Used Tile Attribute Combinations for Type of Tile
17	Number of Used Tile Attributes for Tile Attribute Combination (NUTAFTAC)
	Repeat the following octet for each attribute of tile (n=1,NUTAFTAC)
18 + (n-1)	Attribute of Tile (see code table 4.241)
	end of repetition
19 + (NUTAFTAC-1)	Total Number of Tile Attribute Combinations
20 + (NUTAFTAC-1)	Tile Index
21 + (NUTAFTAC-1) - 36 + (NUTAFTAC-1)	UUID of Data Group
37 + (NUTAFTAC-1)	Type of Generating Process
38 + (NUTAFTAC-1)	Background Process
39 + (NUTAFTAC-1)	Generating Process Identifier
40 + (NUTAFTAC-1) - 41 + (NUTAFTAC-1)	Hours After Data Cut-off
42 + (NUTAFTAC-1)	Minutes After Data Cut-off
43 + (NUTAFTAC-1)	Indicator of Unit of Time Range (see code table 4.4)
44 + (NUTAFTAC-1) - 47 + (NUTAFTAC-1)	Forecast Time
48 + (NUTAFTAC-1)	Type of First Fixed Surface (see code table 4.5)
49 + (NUTAFTAC-1)	Scale Factor of First Fixed Surface
50 + (NUTAFTAC-1) - 53 + (NUTAFTAC-1)	Scaled Value of First Fixed Surface
54 + (NUTAFTAC-1)	Type of Second Fixed Surface (see code table 4.5)
55 + (NUTAFTAC-1)	Scale Factor of Second Fixed Surface
56 + (NUTAFTAC-1) - 59 + (NUTAFTAC-1)	Scaled Value of Second Fixed Surface

ADD new template 4.114 - Average, accumulation, and/or extreme values or other statistically processed values on generalised tiles at a horizontal level or in a horizontal layer in a continuous or non-continuous time interval

Octet	Description
10	Parameter Category (see code table 4.1)
11	Parameter Number (see code table 4.2)
12	Tile Classification (see code table 4.242)
13-14	Type of Tile (see code table 4.251)
15	Number of Used Spatial Tiles
16	Number of Used Tile Attribute Combinations for Type of Tile
17	Number of Used Tile Attributes for Tile Attribute Combination (NUTAFTAC)
	Repeat the following octet for each attribute of tile (n=1,NUTAFTAC)
18 + (n-1)	Attribute of Tile (see code table 4.241)
	end of repetition
19 + (NUTAFTAC-1)	Total Number of Tile Attribute Combinations
20 + (NUTAFTAC-1)	Tile Index
21 + (NUTAFTAC-1) - 36 + (NUTAFTAC-1)	UUID of Data Group
37 + (NUTAFTAC-1)	Type of Generating Process
38 + (NUTAFTAC-1)	Background Process
39 + (NUTAFTAC-1)	Generating Process Identifier
40 + (NUTAFTAC-1) - 41 + (NUTAFTAC-1)	Hours After Data Cut-off
42 + (NUTAFTAC-1)	Minutes After Data Cut-off
43 + (NUTAFTAC-1)	Indicator of Unit of Time Range (see code table 4.4)
44 + (NUTAFTAC-1) - 47 + (NUTAFTAC-1)	Forecast Time
48 + (NUTAFTAC-1)	Type of First Fixed Surface (see code table 4.5)
49 + (NUTAFTAC-1)	Scale Factor of First Fixed Surface
50 + (NUTAFTAC-1) - 53 + (NUTAFTAC-1)	Scaled Value of First Fixed Surface
54 + (NUTAFTAC-1)	Type of Second Fixed Surface (see code table 4.5)
55 + (NUTAFTAC-1)	Scale Factor of Second Fixed Surface
56 + (NUTAFTAC-1) - 59 + (NUTAFTAC-1)	Scaled Value of Second Fixed Surface
60 + (NUTAFTAC-1) - 61 + (NUTAFTAC-1)	Year of End of Overall Time Interval
62 + (NUTAFTAC-1)	Month of End of Overall Time Interval
63 + (NUTAFTAC-1)	Day of End of Overall Time Interval
64 + (NUTAFTAC-1)	Hour of End of Overall Time Interval
65 + (NUTAFTAC-1)	Minute of End of Overall Time Interval
66 + (NUTAFTAC-1)	Second of End of Overall Time Interval
67 + (NUTAFTAC-1)	Number of Time Range
68 + (NUTAFTAC-1) - 71 + (NUTAFTAC-1)	Number of Missing In Statistical Process
72 + (NUTAFTAC-1)	Type of Statistical Processing
73 + (NUTAFTAC-1)	Type of Time Increment
74 + (NUTAFTAC-1)	Indicator of Unit for Time Range
75 + (NUTAFTAC-1) - 78 + (NUTAFTAC-1)	Length of Time Range
79 + (NUTAFTAC-1)	Indicator of Unit for Time Increment (see code table 4.4)
80 + (NUTAFTAC-1) - 83 + (NUTAFTAC-1)	Time Increment

ADD new template 4.115 - Individual ensemble forecast, control and perturbed on generalised tiles at a horizontal level or in a horizontal layer at a point in time

Octet	Description
10	Parameter Category (see code table 4.1)
11	Parameter Number (see code table 4.2)
12	Tile Classification (see code table 4.242)
13-14	Type of Tile (see code table 4.251)
15	Number of Used Spatial Tiles
16	Number of Used Tile Attribute Combinations for Type of Tile
17	Number of Used Tile Attributes for Tile Attribute Combination (NUTAFTAC)
	Repeat the following octet for each attribute of tile (n=1,NUTAFTAC)
18 + (n-1)	Attribute of Tile (see code table 4.241)
	end of repetition
19 + (NUTAFTAC-1)	Total Number of Tile Attribute Combinations
20 + (NUTAFTAC-1)	Tile Index
21 + (NUTAFTAC-1) - 36 + (NUTAFTAC-1)	UUID of Data Group
37 + (NUTAFTAC-1)	Type of Generating Process
38 + (NUTAFTAC-1)	Background Process
39 + (NUTAFTAC-1)	Generating Process Identifier
40 + (NUTAFTAC-1) - 41 + (NUTAFTAC-1)	Hours After Data Cut-off
42 + (NUTAFTAC-1)	Minutes After Data Cut-off
43 + (NUTAFTAC-1)	Indicator of Unit of Time Range (see code table 4.4)
44 + (NUTAFTAC-1) - 47 + (NUTAFTAC-1)	Forecast Time
48 + (NUTAFTAC-1)	Type of First Fixed Surface (see code table 4.5)
49 + (NUTAFTAC-1)	Scale Factor of First Fixed Surface
50 + (NUTAFTAC-1) - 53 + (NUTAFTAC-1)	Scaled Value of First Fixed Surface
54 + (NUTAFTAC-1)	Type of Second Fixed Surface (see code table 4.5)
55 + (NUTAFTAC-1)	Scale Factor of Second Fixed Surface
56 + (NUTAFTAC-1) - 59 + (NUTAFTAC-1)	Scaled Value of Second Fixed Surface
60 + (NUTAFTAC-1)	Type of ensemble forecast (see Code Table 4.6)
61 + (NUTAFTAC-1) - 64 + (NUTAFTAC-1)	Perturbation number
65 + (NUTAFTAC-1) - 68 + (NUTAFTAC-1)	Number of forecasts in ensemble

ADD new template 4.116 - Individual ensemble forecast, control and perturbed on generalised tiles at a horizontal level or in a horizontal layer in a continuous or non-continuous time interval

Octet	Description
10	Parameter Category (see code table 4.1)
11	Parameter Number (see code table 4.2)
12	Tile Classification (see code table 4.242)
13-14	Type of Tile (see code table 4.251)
15	Number of Used Spatial Tiles
16	Number of Used Tile Attribute Combinations for Type of Tile
17	Number of Used Tile Attributes for Tile Attribute Combination (NUTAFTAC)
	Repeat the following octet for each attribute of tile (n=1,NUTAFTAC)
18 + (n-1)	Attribute of Tile (see code table 4.241)
	end of repetition
19 + (NUTAFTAC-1)	Total Number of Tile Attribute Combinations
20 + (NUTAFTAC-1)	Tile Index
21 + (NUTAFTAC-1) - 36 + (NUTAFTAC-1)	UUID of Data Group
37 + (NUTAFTAC-1)	Type of Generating Process
38 + (NUTAFTAC-1)	Background Process
39 + (NUTAFTAC-1)	Generating Process Identifier
40 + (NUTAFTAC-1) - 41 + (NUTAFTAC-1)	Hours After Data Cut-off
42 + (NUTAFTAC-1)	Minutes After Data Cut-off
43 + (NUTAFTAC-1)	Indicator of Unit of Time Range (see code table 4.4)
44 + (NUTAFTAC-1) - 47 + (NUTAFTAC-1)	Forecast Time
48 + (NUTAFTAC-1)	Type of First Fixed Surface (see code table 4.5)
49 + (NUTAFTAC-1)	Scale Factor of First Fixed Surface
50 + (NUTAFTAC-1) - 53 + (NUTAFTAC-1)	Scaled Value of First Fixed Surface
54 + (NUTAFTAC-1)	Type of Second Fixed Surface (see code table 4.5)
55 + (NUTAFTAC-1)	Scale Factor of Second Fixed Surface
56 + (NUTAFTAC-1) - 59 + (NUTAFTAC-1)	Scaled Value of Second Fixed Surface
60 + (NUTAFTAC-1)	Type of ensemble forecast (see Code Table 4.6)
61 + (NUTAFTAC-1) - 64 + (NUTAFTAC-1)	Perturbation number
65 + (NUTAFTAC-1) - 68 + (NUTAFTAC-1)	Number of forecasts in ensemble
69 + (NUTAFTAC-1) - 70 + (NUTAFTAC-1)	Year of End of Overall Time Interval
71 + (NUTAFTAC-1)	Month of End of Overall Time Interval
72 + (NUTAFTAC-1)	Day of End of Overall Time Interval
73 + (NUTAFTAC-1)	Hour of End of Overall Time Interval
74 + (NUTAFTAC-1)	Minute of End of Overall Time Interval
75 + (NUTAFTAC-1)	Second of End of Overall Time Interval
76 + (NUTAFTAC-1)	Number of Time Range
77 + (NUTAFTAC-1) - 80 + (NUTAFTAC-1)	Number of Missing In Statistical Process
81 + (NUTAFTAC-1)	Type of Statistical Processing
82 + (NUTAFTAC-1)	Type of Time Increment
83 + (NUTAFTAC-1)	Indicator of Unit for Time Range
84 + (NUTAFTAC-1) - 87 + (NUTAFTAC-1)	Length of Time Range
88 + (NUTAFTAC-1)	Indicator of Unit for Time Increment (see code table 4.4)
89 + (NUTAFTAC-1) - 92 + (NUTAFTAC-1)	Time Increment

add Code Table 4.252 - Tile classes and groupings

Code		Description
0		Reserved
1	SEOC	Seas and oceans
2	INWB	Inland water bodies
3	BARE	Bare areas
4	HIV	High vegetation
5	LOV	Low vegetation
6	URBAN	Urban
7-1000		Reserved (see Note XXX: Reserved for intercomparison tile classes/groupings)
1001	SEAO	Sea and oceans
1002	LAKE	Lakes
1003	RIVE	Rivers
1004	NO	Bare land
1005	ROCK	Bare rock
1006	SNOW	Permanent snow
1007	BOBD	Boreal broadleaf deciduous
1008	TEBD	Temperate broadleaf deciduous
1009	TRBD	Tropical broadleaf deciduous
1010	TEBE	Temperate broadleaf evergreen
1011	TRBE	Tropical broadleaf evergreen
1012	BONE	Boreal needleleaf evergreen
1013	TENE	Temperate needleleaf evergreen
1014	BOND	Boreal needleleaf deciduous
1015	SHRB	Shrubs
1016	BOGR	Boreal grassland
1017	GRAS	Temperate grassland
1018	TROG	Tropical grassland
1019	C3W	Winter C3 crops
1020	C3S	Summer C3 crops
1021	C4	C4 crops
1022	FLTR	Flooded trees
1023	FLGR	Flooded grassland
1024	LCZ1	Local climate zone 1: compact high-rise (buildings)
1025	LCZ2	Local climate zone 2: compact midrise (buildings)
1026	LCZ3	Local climate zone 3: compact low-rise (buildings)
1027	LCZ4	Local climate zone 4: open high-rise (buildings)
1028	LCZ5	Local climate zone 5: open midrise (buildings)
1029	LCZ6	Local climate zone 6: open low-rise (buildings)
1030	LCZ7	Local climate zone 7: lightweight low-rise (buildings)
1031	LCZ8	Local climate zone 8: large low-rise (buildings)
1032	LCZ9	Local climate zone 9: sparsely built (buildings)
1033	LCZ10	Local climate zone 10: heavy industry (buildings)
1034	TEBDU	Urban temperate broadleaf deciduous
1035	TRBDU	Urban tropical broadleaf deciduous
1036	TEBEU	Urban temperate broadleaf evergreen
1037	TRBEU	Urban tropical broadleaf evergreen
1038	BONEU	Urban boreal needleleaf evergreen
1039	TENEU	Urban temperate needleleaf evergreen
1040	BONDU	Urban boreal needleleaf deciduous
1041-1500		Reserved (see Note XXX: Reserved for tile class entries for tile models using the ECOCLIMAP-SG land cover survey)
1501		Nature grouping (NO + ROCK + SNOW + BOBD + TEBD + TRBD + TEBE + TRBE + BONE + TENE + BOND + SHRB + BOGR + GRAS + TROG + C3W + C3S + C4 + FLTR + FLGR)
1502		Non-forest grouping (NO + ROCK + SNOW + BOGR + GRAS + TROG + C3W + C3S + C4 + FLTR + FLGR)
1503		Forest grouping (BOBD + TEBD + TRBD + TEBE + TRBE + BONE + TENE + BOND + SHRB)
1504		Non-vegetated grouping (NO + ROCK + SNOW)
1505		Trees grouping (BOBD + TEBD + TRBD + TEBE + TRBE + BONE + TENE + BOND + SHRB + FLTR)
1506		Low vegetation grouping (BOGR + GRAS + TROG + C3W + C3S + C4 + FLGR)
1507		Non-flooded low vegetation grouping (BOGR + GRAS + TROG + C3W + C3S + C4)
1508		Crops grouping (C3W + C3S + C4)
1509		Grassland grouping (BOGR + GRAS + TROG)
1510		Bare and rock grouping (NO + ROCK)
1511		C3 crops grouping (C3W + C3S)
1512		Broadleaf forest grouping (BOBD + TEBD + TRBD + TEBE + TRBE + SHRB)
1513		Needleleaf forest grouping (BONE + TENE + BOND)
1514		Deciduous broadleaf forest grouping (BOBD + TEBD + TRBD + TEBE + SHRB)
1515		Temperate grassland grouping (BOGR + GRAS)
1516		Non-forest (no FLTR) grouping (NO + ROCK + SNOW + BOGR + GRAS + TROG + C3W + C3S + C4 + FLGR)
1517		Broadleaf forest (with FLTR) grouping (BOBD + TEBD + TRBD + TEBE + TRBE + SHRB + FLTR)
1518		Broadleaf trees grouping (BOBD + TEBD + TRBD + TEBE + TRBE + FLTR)
1519		C3/C4 grasslands grouping (BOGR + GRAS + FLGR)
1520		Broadleaf deciduous trees grouping (BOBD + TEBD + TRBD + FLTR)
1521		Broadleaf evergreen trees grouping (TEBE + TRBE)
1522		Needleleaf evergreen trees grouping (BONE + TENE)
1523		LCZ or urban grouping (LCZ1 + LCZ2 + LCZ3 + LCZ4 + LCZ5 + LCZ6 + LCZ7 + LCZ8 + LCZ9 + LCZ10)
1524		Inland water grouping (LAKE + RIVE)
1525		Urban parks and gardens TEBD grouping (NO + GRAS + TEBDU)
1526		Urban parks and gardens TRBD grouping (NO + GRAS + TRBDU)
1527		Urban parks and gardens TEBE grouping (NO + GRAS + TEBEU)
1528		Urban parks and gardens TRBE grouping (NO + GRAS + TRBEU)
1529		Urban parks and gardens BONE grouping (NO + GRAS + BONEU)
1530		Urban parks and gardens TENE grouping (NO + GRAS + TENEU)
1531		Urban parks and gardens BOND grouping (NO + GRAS + BONDU)
1532-2000		Reserved (see Note XXX: Reserved for tile grouping entries for tile models using the ECOCLIMAP-SG land cover survey)
2001	CRMF	Crops, mixed farming
2002	SHGR	Short grass
2003	EVNE	Evergreen needleleaf trees
2004	DENE	Deciduous needleleaf trees
2005	DEBR	Deciduous broadleaf trees
2006	EVBR	Evergreen broadleaf trees
2007	TAGR	Tall grass
2008	DESE	Desert
2009	TUND	Tundra
2010	IRCR	Irrigated crops
2011	SEDE	Semidesert
2012	ICGL	Ice caps and glaciers
2013	BOMA	Bogs and marshes
2014	INWA	Inland water
2015	OCEA	Ocean
2016	EVSH	Evergreen shrubs
2017	DESH	Deciduous shrubs
2018	MFWO	Mixed forest/woodland
2019	INFO	Interrupted forest
2020	WLMI	Water and land mixtures
2021	BASO	Bare soil
2022	URBA	Urban
2023	LORI	Low-rise building
2024	HIRI	High-rise building
2025-2500		Reserved (see Note XXX: Reserved for tile class entries for tile models using the GLCC v2.0 BATS Classification survey)
2501		Low vegetation grouping (CRMF + SHGR + TAGR + TUND + IRCR + SEDE + BOMA + EVSH + DESH + WLMI)
2502		High vegetation grouping (EVNE + DENE + DEBR + EVBR + MFWO + INFO)
2503-3000		Reserved (see Note XXX: Reserved for tile grouping entries for tile models using the GLCC v2.0 BATS Classification survey)
3001	PFIC	Post-flooding or irrigated croplands
3002	RACR	Rainfed croplands
3003	MCVE	Mosaic cropland (50-70%) / vegetation (grassland, shrubland, forest) (20-50%)
3004	MVCR	Mosaic vegetation (grassland, shrubland, forest) (50-70%) / cropland (20-50%)
3005	COBS	Closed to open (>15%) broadleaved evergreen and/or semi-deciduous forest (>5m)
3006	CLBD	Closed (>40%) broadleaved deciduous forest (>5m)
3007	OPBD	Open (15-40%) broadleaved deciduous forest (>5m)
3008	CLNE	Closed (>40%) needleleaved evergreen forest (>5m)
3009	ONDE	Open (15-40%) needleleaved deciduous or evergreen forest (>5m)
3010	COBN	Closed to open (>15%) mixed broadleaved and needleleaved forest (>5m)
3011	MFSG	Mosaic forest/shrubland (50-70%) / grassland (20-50%)
3012	MGFS	Mosaic grassland (50-70%) / forest / shrubland (20-50%)
3013	COSH	Closed to open (>15%) shrubland (<5m)
3014	COHV	Closed to open (>15%) herbaceous vegetation
3015	SPVE	Sparse (<15%) vegetation (woody vegetation, shrubs, grassland)
3016	COBFF	Closed to open (>15%) broadleaved forest regularly flooded (semi-permanently or temporarily) - fresh or brackish water
3017	CLBFF	Closed (>40%) broadleaved forest or shrubland permanently flooded - saline or brackish water
3018	COVEF	Closed to open (>15%) vegetation (grassland, shrubland, woody vegetation) on regularly flooded or waterlogged soil - fresh, brackish or saline water
3019	ASAA	Artificial surfaces and associated areas (urban areas >50%)
3020	BAAR	Bare areas
3021	WABO	Water bodies
3022	PESI	Permanent snow and ice
3023-3500		Reserved (see Note XXX: Reserved for tile class entries for tile models using the ESA-GlobCover GCV2009 survey)
3501		Grouping using the dominant tiles approach (dominant tile varies per gridbox)
3502-4000		Reserved (see Note XXX: Reserved for tile grouping entries for tile models using the ESA-GlobCover GCV2009 survey)
4001	TBECO	Tree cover, broadleaved evergreen, closed to open (>15%)
4002	TBDC	Tree cover, broadleaved deciduous, closed (>40%)
4003	TBDO	Tree cover, broadleaved deciduous, open (15-40%)
4004	TNECO	Tree cover, needleleaved evergreen, closed to open (>15%)
4005	TNDCO	Tree cover, needleleaved decidous, closed to open (>15%)
4006	TMLCO	Tree cover, mixed leaftype, closed to open (>15%)
4007	TCOFF	Tree cover, closed to open (>15%), regularly flooded, fresh or brackish water: swamp forests
4008	TCOFS	Tree cover, closed to open (>15%), regularly flooded, saline water: mangrove forests
4009	MTVG	Mosaic of tree cover and other natural vegetation (crop component possible)
4010	TBURN	Tree Cover, burnt (mainly boreal forests)
4011	SCOE	Shrubcover, closed to open (>15%) , evergreen (broadleaved or needleleaved)
4012	SCOD	Shrubcover, closed to open (>15%), deciduous (broadleaved)
4013	HCCO	Herbaceous cover, closed to open (>15%)
4014	SHSC	Sparse herbaceous or sparse shrub cover
4015	FSHCO	Regularly flooded (>2 month) shrub or herbaceous cover, closed to open
4016	CROP	Cropland (upland crops or inundated/ flooded crops)
4017	MCTNV	Mosaic of cropland / tree cover/ other natural vegetation
4018	MCSH	Mosaic of cropland / shrub or herbaceous cover
4019	BAARE	Bare areas
4020	WBNA	Water bodies (natural or artificial)
4021	SINA	Snow or ice (natural or artificial)
4022	URAR	Urban areas
4023-4500		Reserved (see Note XXX: Reserved for tile class entries for tile models using the European Commission-Global Land Cover Project GLC2000 survey)
4501-5000		Reserved (see Note XXX: Reserved for tile grouping entries for tile models using the European Commission-Global Land Cover Project GLC2000 survey)
5001-32767		Reserved for additional land cover surveys
32768-65534		Reserved for local use
65535		Missing

Comments

No response

Requestor(s)

Matthew Griffith (ECMWF)
Sebastien Villaume (ECMWF)

Stakeholder(s)

ECMWF, Meteo France, SMHI, DMI, FMI, Met Norway and DWD

Publication(s)

Manual on Codes (WMO-No. 306), Volume I.2, GRIB section 4, product definition template number 113 (new)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB section 4, product definition template number 114 (new)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB section 4, product definition template number 115 (new)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB section 4, product definition template number 116 (new)
Manual on Codes (WMO-No. 306), Volume I.2, Code Table 4.251 (new)
Manual on Codes (WMO-No. 306), Volume I.2, Code Table 4.0 (add entries)
Manual on Codes (WMO-No. 306), Volume I.2, Code Table 4.241 (add entries)
Manual on Codes (WMO-No. 306), Volume I.2, Code Table 4.242 (add entries)

Expected impact of change

MEDIUM

Collaborators

ECMWF, MeteoFrance, SMHI, DWD

References

No response

Validation

We can provide an ecCodes version which encode/decodes GRIB2 messages making use of the features described in this proposal

[chenxiaoxia2019]

25-April meeting: Sebastian to provide ecCodes version which encode/decodes GRIB2 messages

[sebvi]

a version of eccodes for the tile template can be obtain here: eccodes

[amilan17]

https://github.com/wmo-im/CCT/wiki/Teleconference.6.7.June.2023 notes:

samples are available; @sebvi update branch

[sebvi]

Branch is updated

[amilan17]

https://github.com/wmo-im/CCT/wiki/Teleconference.13.July.2023 notes:

Sebastien is responding to Anna's review in PR; @sebvi will provide samples and @SibylleK will do technical validation within a week; the FT proposal can be circulated to stakeholders/contributors during the NFP review;

[sebvi]

an up-to-date eccodes is available here: eccodes

I have created some samples to download:
WMO_tile.tar.zip

[amilan17]

Branches look good with one question remaining in PR.

[amilan17]

Branches look good with one question remaining in PR.

Can't find question. I assume I was mistaken! 

@SibylleK to validate?

[SibylleK]

I tried to decode the provided example using the csv files of the branch.

As in the templates the "attribute of tile" should rather be a list of NUTAFTAC attributes, I am not satisfied with the notation.
My suggestion would be:

Octet	Description
12	Tile Classification (see code table 4.242)
13-14	Type of Tile (see code table 4.251)
15	Number of Used Spatial Tiles
16	Number of Used Tile Attribute Combinations for Type of Tile
17	Number of Used Tile Attributes for Tile Attribute Combination (NUTAFTAC)
.	Repeat the following octet for each attribute of tile (n=1,NUTAFTAC)
18+1(n-1)	List of attribute of tile (see code table 4.241)
..	..

Regarding 4.116 - Individual ensemble forecast, control and perturbed on generalised tiles at a horizontal level or in a horizontal layer in a continuous or non-continuous time interval
the GRIB2 example and the proposal differ!

In the example the ensemble entries (i.e. Type of ensemble forecast, Perturbation number and Number of forecasts in ensemble) comes after the second fixed surface. In the proposal and the branch they are at the end of the template.

As in most (if not all) ensemble PDTs these entries come after the fixed surface types, I rather suppose changing the proposal.

With these changes I was able to read the entries in section 4 of the GRIB examples with a DWD GRIB reader software.
The entries were the same as in an output of eccodes grib_dump.
In that case the proposal has been validated.

@sebvi @amilan17 shall I update the branch?

[sebvi]

dear @SibylleK , thank you for validating the templates. I an on annual leave at the moment but I will have a look at your comments later this evening.

[sebvi]

Dear @SibylleK , I have now reviewed your comments and I fully agree with you.

• we can make clearer that the number of attributes of tiles triggers to read a list of attributes and it is not very clear in the eway it is presented in the proposal.
• I had the same remark as you regarding the position of the keys for the ensemble in templates 4.115 and 4.116 and this is why it was changed in the ecCodes branch and in the samples. It seems that we never updated the word document I used when I copied it over in the issue. So I need to change it in the proposal and in the branch

[sebvi]

I have updated the proposal and will update the branch tomorrow morning

[sebvi]

I have updated the branch

[amilan17]

@SibylleK -- Did you want to check this again or shall we consider it validated?

[SibylleK]

@amilan17, I double checked and the updated branch is OK. It can be considered validated.