Alternative implementation of the Hazards indices describes in #285

[sebvi]

Initial request

Following the discussion in issue #254 and #285, we will now also consider templates to implement the hazard indices in GRIB2. We will need ensemble and non-ensemble variants as well as instant and time-processed variants. Thus, the proposition below. We extend Table 4.0 to add the new templates, add a general hazard index parameter, add 4 new templates, an additional code table containing the hazard profiles, and an additional table for the value of the hazard index.

Amendment details

ADD to code table 4.0 Product definition template number

Code	Description
148	Analysis or forecast at a horizontal level or in a horizontal layer at a point in time for hazards
149	Individual ensemble forecast, control and perturbed, at a horizontal level or in a horizontal layer at a point in time for hazards
150	Average, accumulation, 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 hazards
151	Individual ensemble forecast, control and perturbed, at a horizontal level or in a horizontal layer, in a continuous or non-continuous interval, for hazards

ADD to code table 4.2: Product discipline 20 - Health and socioeconomic impacts, parameter category X: ???

Code	Description	Unit
0	Hazard index	(Code table 4.254)

TEMPLATE 4.148, Analysis or forecast at a horizontal level or in a horizontal layer at a point in time for hazards

Octet	Number of octets	Description
10	1	Parameter Category (see code table 4.1)
11	1	Parameter Number (see code table 4.2)
12-13	2	Hazard Profile (see Code Table 4.253)
14-15	2	Input process Identifier (See Note 1)
16-17	2	Input originating centre (see Common Code table C-11 and Note 2)
18	1	Type of Generating Process (see code table 4.3)
19	1	Background Process
20	1	Generating Process Identifier
21-22	2	Hours After Data Cut-off
23	1	Minutes After Data Cut-off
24	1	Indicator of Unit of Time Range (see code table 4.4)
25- 28	4	Forecast Time
29	1	Type of First Fixed Surface (see code table 4.5)
30	1	Scale Factor of First Fixed Surface
31-34	4	Scaled Value of First Fixed Surface
35	1	Type of Second Fixed Surface (see code table 4.5)
36	1	Scale Factor of Second Fixed Surface
37-40	4	Scaled Value of Second Fixed Surface

Notes:

• 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.
• The input originating centre shall have the value of the "originating centre" of the original GRIB message used as input of the post-processing.

TEMPLATE 4.149 Individual ensemble forecast, control and perturbed, at a horizontal level or in a horizontal layer at a point in time for hazards

Octet	Number of octets	Description
10	1	Parameter Category (see code table 4.1)
11	1	Parameter Number (see code table 4.2)
12-13	2	Hazard Profile (see Code Table 4.253)
14-15	2	Input process Identifier (See Note 1)
16-17	2	Input originating centre (see Common Code table C-11 and Note 2)
18	1	Type of Generating Process (see code table 4.3)
19	1	Background Process
20	1	Generating Process Identifier
21-22	2	Hours After Data Cut-off
23	1	Minutes After Data Cut-off
24	1	Indicator of Unit of Time Range (see code table 4.4)
25- 28	4	Forecast Time
29	1	Type of First Fixed Surface (see code table 4.5)
30	1	Scale Factor of First Fixed Surface
31-34	4	Scaled Value of First Fixed Surface
35	1	Type of Second Fixed Surface (see code table 4.5)
36	1	Scale Factor of Second Fixed Surface
37-40	4	Scaled Value of Second Fixed Surface
41	1	Type of Ensemble Forecast (see code table 4.6)
42-45	4	Perturbation Number
46-49	4	Number of Forecasts in Ensemble

Notes:

• 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.
• The input originating centre shall have the value of the "originating centre" of the original GRIB message used as input of the post-processing.

TEMPLATE 4.150, Average, accumulation, 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 hazards

Octet	Number of octets	Description
10	1	Parameter Category (see code table 4.1)
11	1	Parameter Number (see code table 4.2)
12-13	2	Hazard Profile (see Code Table 4.253)
14-15	2	Input process Identifier (See Note 1)
16-17	2	Input originating centre (see Common Code table C-11 and Note 2)
18	1	Type of Generating Process (see code table 4.3)
19	1	Background Process
20	1	Generating Process Identifier
21-22	2	Hours After Data Cut-off
23	1	Minutes After Data Cut-off
24	1	Indicator of Unit of Time Range (see code table 4.4)
25- 28	4	Forecast Time
29	1	Type of First Fixed Surface (see code table 4.5)
30	1	Scale Factor of First Fixed Surface
31-34	4	Scaled Value of First Fixed Surface
35	1	Type of Second Fixed Surface (see code table 4.5)
36	1	Scale Factor of Second Fixed Surface
37-40	4	Scaled Value of Second Fixed Surface
41-42	2	Year of end of overall time interval
43	1	Month of end of overall time interval
44	1	Day of end of overall time interval
45	1	Hour of end of overall time interval
46	1	Minute of end of overall time interval
47	1	Second of end of overall time interval
48	1	n - number of time range specifications describing the time intervals used to calculate the statistically processed field
49-52	4	Total number of data values missing in statistical process
		53 - 64 Specification of the outermost (or only) time range over which statistical processing is done
53	1	Statistical process used to calculate the processed field from the field at each time increment during the time range (see code table 4.10)
54	1	Type of time increment between successive fields used in the statistical processing (see code table 4.11)
55	1	Indicator of unit of time for time range over which statistical processing is done (see code table 4.4)
56-59	4	Length of the time range over which statistical processing is done, in units defined by the previous octet
60	1	Indicator of unit of time for the increment between the successive fields used (see code table 4.4)
61-64	4	Time increment between successive fields, in units defined by the previous octet
		65 - nn These octets are included only if n > 1, where nn = 53+ 12 x n
65-76	12	As octets 53 to 64, next innermost step of processing
77-nn	n/a	Additional time range specifications, included in accordance with the value of n. Contents as octets 53 to 64, repeated as necessary

Notes:

• 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.
• The input originating centre shall have the value of the "originating centre" of the original GRIB message used as input of the post-processing.

TEMPLATE 4.151, Individual ensemble forecast, control and perturbed, at a horizontal level or in a horizontal layer, in a continuous or non-continuous interval, for hazards

Octet	Number of octets	Description
10	1	Parameter Category (see code table 4.1)
11	1	Parameter Number (see code table 4.2)
12-13	2	Hazard Profile (see Code Table 4.253)
14-15	2	Input process Identifier (See Note 1)
16-17	2	Input originating centre (see Common Code table C-11 and Note 2)
18	1	Type of Generating Process (see code table 4.3)
19	1	Background Process
20	1	Generating Process Identifier
21-22	2	Hours After Data Cut-off
23	1	Minutes After Data Cut-off
24	1	Indicator of Unit of Time Range (see code table 4.4)
25- 28	4	Forecast Time
29	1	Type of First Fixed Surface (see code table 4.5)
30	1	Scale Factor of First Fixed Surface
31-34	4	Scaled Value of First Fixed Surface
35	1	Type of Second Fixed Surface (see code table 4.5)
36	1	Scale Factor of Second Fixed Surface
37-40	4	Scaled Value of Second Fixed Surface
41	1	Type of Ensemble Forecast (see code table 4.6)
42-45	4	Perturbation Number
46-49	4	Number of Forecasts in Ensemble
50-51	2	Year of end of overall time interval
52	1	Month of end of overall time interval
53	1	Day of end of overall time interval
54	1	Hour of end of overall time interval
55	1	Minute of end of overall time interval
56	1	Second of end of overall time interval
57	1	n - number of time range specifications describing the time intervals used to calculate the statistically processed field
58-61	4	Total number of data values missing in statistical process
		62 - 73 Specification of the outermost (or only) time range over which statistical processing is done
62	1	Statistical process used to calculate the processed field from the field at each time increment during the time range (see code table 4.10)
63	1	Type of time increment between successive fields used in the statistical processing (see code table 4.11)
64	1	Indicator of unit of time for time range over which statistical processing is done (see code table 4.4)
65-68	4	Length of the time range over which statistical processing is done, in units defined by the previous octet
69	1	Indicator of unit of time for the increment between the successive fields used (see code table 4.4)
70-73	4	Time increment between successive fields, in units defined by the previous octet
		74 - nn These octets are included only if n > 1, where nn = 62+ 12 x n
74-85	12	As octets 62 to 73, next innermost step of processing
86-nn	n/a	Additional time range specifications, included in accordance with the value of n. Contents as octets 62 to 73, repeated as necessary

Notes:

• 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.
• The input originating centre shall have the value of the "originating centre" of the original GRIB message used as input of the post-processing.

ADD new Code Table 4.253, Hazard profiles

Code	Description
0	Reserved
1	Downburst
2	Lightning (Electrical Storm)
3	Thunderstorm
4	Coastal Flood
5	Estuarine (Coastal) Flood
6	Flash Flood
7	Fluvial (Riverine) Flood
8	Groundwater Flood
9	Ice-Jam Flood Including Debris
10	Ponding (Drainage) Flood
11	Snowmelt Flood
12	Surface Water Flooding
13	Glacial Lake Outburst Flood
14	Black Carbon (Brown Clouds)
15	Dust storm or Sandstorm
16	Fog
17	Haze
18	Polluted Air
19	Sand haze
20	Smoke
21	Ocean Acidification
22	Rogue Wave
23	Sea Water Intrusion
24	Sea Ice (Ice Bergs)
25	Ice Flow
26	Seiche
27	Storm Surge
28	Storm Tides
29	Tsunami
30	Depression or Cyclone (Low Pressure Area) (Pressure-Related)
31	Extra-tropical Cyclone (Pressure-Related)
32	Sub-Tropical Cyclone (Pressure-Related)
33	Acid Rain
34	Blizzard
35	Drought
36	Hail
37	Ice Storm
38	Snow
39	Snow Storm
40	Cold Wave
41	Dzud
42	Freeze
43	Frost (Hoar Frost)
44	Freezing Rain (Supercooled Rain)
45	Glaze
46	Ground Frost
47	Heatwave
48	Icing (Including Ice)
49	Thaw
50	Avalanche
51	Mud Flow
52	Rock slide
53	Derecho
54	Gale (Strong Gale)
55	Squall
56	Subtropical Storm
57	Tropical Cyclone (Cyclonic Wind, Rain [Storm] Surge) (Wind-Related)
58	Tropical Storm (Wind-Related)
59	Tornado
60	Wind
61-100	Reserved for meteorological and hydrological hazard indices
101	Household Air Pollution
102	Air Pollution (Point Source)
103	Ambient (Outdoor) Air Pollution
104	Land Degradation
105	Soil Degradation
106	Runoff / Nonpoint Source Pollution
107	Salinity
108	Biodiversity Loss
109	Deforestation
110	Forest Declines and Diebacks
111	Forest Disturbances
112	Forest Invasive Species
113	Wildfires
114	Desertification
115	Loss of Mangroves
116	Wetland Loss/Degradation
117	Coral Bleaching
118	Compressive Soils
119	Soil Erosion
120	Coastal Erosion and Shoreline Change
121	Permafrost Loss
122	Sand Mining
123	Sea Level Rise
124	Eutrophication
125-200	Reserved for environmental hazard indices
201-32767	Reserved for additional official hazard indices
32768-65534	Reserved for local use
65535	Missing

ADD new Code Table 4.254, Hazard index

Code	Description
0	Undefined
1-191	Reserved (see Note 1)
192-254	Reserved for local use
255	Missing

Notes:

• The hazard index can be locally defined by the centre.

Comments

No response

Requestor(s)

Sebastien Villaume (ECMWF)
Matthew Griffith (ECMWF)
Robert Osinski (ECMWF)

Stakeholder(s)

ECMWF
Destination Earth

Publication(s)

Manual on Codes (WMO-No. 306), Volume I.2, GRIB code table 4.0 (update)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB code table 4.2.20.X (update)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB code table 4.253 (create)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB code table 4.254 (create)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB Template 4.148 (create)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB Template 4.149 (create)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB Template 4.150 (create)
Manual on Codes (WMO-No. 306), Volume I.2, GRIB Template 4.151 (create)

Expected impact of change

None

Collaborators

No response

References

No response

Validation

No response

[amilan17]

https://github.com/wmo-im/et-data/wiki/2024.12.03.et.data notes:
Matthew introduced the alternate proposal, using the same idea of #285 but adding new templates instead to encode the octet; values are from a UN WMO hazard profile document; there was a discussion about referring to code tables in the units column; Debbie said it would be less clunky to use the #285 approach;

• the team decided that New categories for Hazard indices in discipline 20 [Code Table 4.1 and 4.2 and new Code table 4.253] #285 is the better approach.