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Rules for allocating WMO numbers

What is a WMO number and how to get/allocate WMO numbers?

WMO numbers are allocated for ocean platforms reporting on GTS. WMO numbers are allocated depending upon platform type, and deployment area (see table and map below). Considered platform types are drifting buoys, moored buoys, ocean reference sites, gliders, profiling floats (Argo), and marine animals equipped with instrumentation for measuring geo-physical variables .

General form of a WMO number is [V]A1bwnnn or [V]A1bwnnnnn:

  • The letter "V" is optional, and is used only for allocating numbers to virtual platforms (e.g. reference points). The same rules as below then apply to the remaining part of the WMO number (A1bwnnn or A1bwnnnnn). When the letter "V" is used,it shall always be included with the WMO number as it is an integral part of it in that case. The corresponding "virtual observational" reports shall by no way be distributed on the GTS as they are not real-observations.
  • A1bw represents the WMO regional association area (A1) and the sub-area (bw) belonging to the area indicated by A1 where the platform is being deployed (regional association area not defined for marine animals; sub-area not defined for profiling floats, ocean sites, gliders, and marine animals). Figure 1 provides for the possible values of A1bw, noting that in the peri-Antarctic regions, A1 is coded '7' in FM-18 BUOY code but it is coded '0' in FM-94 BUFR reports (BUFR code table 0 01 003).

  • nnn or nnnnn is the serial number assigned to the platform for that WMO region and sub-area corresponding to the deployment area. Serial numbers are allocated depending upon platform type as shown in the table below.The rules for using of the short or extended form are defined in the table below.

  • Numbers in the form A1bwnnn are considered equivalent to the form A1bw00nnn. In addition, in order to avoid allocating a 7-digit WMO number to a new buoy with this 7-digit number being equivalent to a 5-digit WMO number of an existing buoy, all newly allocated 7-digit WMO numbers in the form A1bwnnnnn have always the nnnnn part ≥ 1000 (in other words the 7-digit numbers where nnnnn < 1000 are reserved for the 5-digit equivalence.)

Reallocation, uniqueness:

  • For drifting and moored buoys using the short form A1bwnnn, provided that buoy type and deployment area does not change, WMO number can be reallocated to a new buoy, 3 months at the earliest after the end of the buoy operational life-time. In the contrary, if your buoy programme stops and you do not intend to deploy buoys in the future, please release the WMO numbers to your National Focal Point.

  • For buoys reporting in BUFR or CREX and using the extended form A1bwnnnnn; for ocean sites; gliders; profiling floats; and marine animals, they are unique and can’t therefore be reallocated.

Table 1: rules for WMO number allocation

Platform type

Format

Reporting code form

Deployment area

Serial no.

Reallocation

Comment

Drifting buoys

A1bwnnn

BUOY, BUFR, CREX

A1=WMO region, bw=sub-area

nnn: 500 to 999

Yes, after 3 months

Surface drifting buoys, http://www.jcommops.org/dbcp/
Twin number A 1bwxxx with xxx=nnn-500 can be used for a moored buoy.

Drifting buoys (table driven codes only) A1bwnnnnn BUFR, CREX A1=WMO region, bw=sub-area nnnnn: xx500 to xx999 with xx: 00 to 99 No, unique numbers Surface drifting buoys, http://www.jcommops.org/dbcp/
No twin number (i.e. A 1bwxxxxx with xxxxx=nnnnn-500 allocated to a moored buoy separately/ independently ).

Moored buoys

A1bwnnn

BUOY, BUFR, CREX, SHIP

A1=WMO region, bw=sub-area

nnn: 000 to 499

Yes, after 3 months

Surface meteorological and/or oceanographic buoys, http://www.jcommops.org/dbcp/
Twin number A 1bwxxx with xxx=500+nnn can be used for a drifting buoy.

Moored buoys (table driven codes only) A1bwnnnnn BUFR, CREX A1=WMO region, bw=sub-area nnnnn: xx000 to xx499 with xx: 00 to 99 No, unique numbers Surface meteorological and/or oceanographic buoys, http://www.jcommops.org/dbcp/
Ni twin number (i.e. A 1bwxxxxx with xxxxx=500+nnnnn allocated to a drifter separately/ independently ).

Ocean sites

A184nn

BUOY

A1=WMO region

nn: 00 to 99

No, unique numbers

Ocean reference sites, http://www.oceansites.org/

bw forced to 8
Twin number A189nn can be used for a glider

Ocean sites (table driven codes only) A18nnnnn BUFR, CREX A1=WMO region

nnnnn: xx000 to xx499 with

xx: 00 to 99
No, unique numbers

Ocean reference sites, http://www.oceansites.org/

bw forced to 8
No twin number (i.e. A18xxxxx with xxxxx=nnnnn+500 allocated to a glider separately/ independently )
Gliders A189nn

BUOY, TESAC,

BUFR, CREX

A1=WMO region nn: 00 to 99 No, unique numbers bw forced to 8
Twin number A184nn can be used for an OceanSITE
Gliders (table driven codes only) A18nnnnn BUFR, CREX A1=WMO region

nnnnn: xx500 to xx999 with

xx: 00 to 99
No, unique numbers

Ocean reference sites, http://www.oceansites.org/

bw forced to 8
No twin number (i.e. A18xxxxx with xxxxx=nnnnn-500 allocated to an OceanSITE separately/ independently )

Profiling floats

A19nnnnn

TESAC, BUFR

A1=WMO region

nnnnn: 00000 to 99999

No, unique numbers

bw forced to 9
Argo profiling floats, http://argo.jcommops.org/
When using character code TESAC, the WMO number is preceded with the letter Q.

Marine animals 99nnnnn TESAC, BATHY, BUFR, CREX Any nnnnn: 00000 to 99999 No, unique numbers

A1 forced to 9; bw forced to 9.

When using character code TESAC or BATHY, the WMO number is preceded with the letter Q.


Obtaining WMO numbers
: Blocks of WMO numbers are allocated to the countries by the WMO Secretariat (see WMO block allocation here). National Focal Points for buoy programmes are responsible for allocating the WMO numbers nationally.

For obtaining WMO numbers, contact your National Focal Point and provide him/her with following information and he/she will provide you with the required WMO numbers:

  1. Platform type (drifting buoy, moored buoy, ocean site, profiling float)
  2. Number of platforms of the type above, and for each platform:
  3. Approximate deployment area (see map below)
  4. International programme in which the buoy participates, if any.

If there is no National Focal point in your country, then you can contact the WMO Secretariat directly (see contact details here), the Technical Coordinator of the DBCP (buoys), or the Argo Technical Coordinator (profiling floats). The latter two (see contact details here) can also contact the appropriate National Focal Point on your behalf if desired.

Figure 1: WMO regional association area (A1, 1st digit) and sub-area (bw, 2nd digit) for allocation of WMO numbers based upon buoy deployment area

WMO areas

Notes:

  • Drifting and moored buoys: When using the short form (5-digit numbers), a pair of WMO numbers is allocated each time to a country; one number can be used for a moored buoy, and the other one for a drifting buoy. Only the moored buoy number (i.e. in the series nnn from 000 to 499) is indicated when allocating the pair. The drifting buoy number is automatically deduced by adding 500 to the indicated number (i.e. the drifting buoy number will be in the form of A1bwxxx with xxx = 500+nnn). Until 1997 WMO numbers in the series nnn from 300 to 350 were allocated to TAO buoys. Until 1997 WMO numbers in the series nnn from 400 to 499 were allocated to WOCE buoys. As of 2007, per DBCP-22 recommendation, extended WMO numbers (7-digit numbers) may be used provided the data are being reported in BUFR or CREX. WMO numbers are not allocated in pairs in case of the extended form.

  • OceanSITES and Gliders: When using the short form (5-digit numbers), a pair of WMO numbers is allocated each time to a country; one number can be used for an OceanSITE, and the other one for a glider. Only the OceanSITE number (i.e. A184nn) is indicated when allocating the pair. The glider number is automatically deduced by adding 500 to the indicated number (i.e. the glider number will be in the form of A189nn). As of 2007, per DBCP-22 recommendation, extended WMO numbers (7-digit numbers) may be used provided the data are being reported in BUFR or CREX. WMO numbers are not allocated in pairs in case of the extended form.

  • Argo profiling floats: Observational data from profiling sub-surface floats deployed under Argo and similar projects are distributed on the GTS in TESAC or BUFR code. The Data Buoy Cooperation Panel (DBCP) has developed an extension of the existing buoy identifier system to facilitate easy identification of the reports from these floats, as well as retain a unique ID number for all floats deployed (without recycling). When using TESAC, the identifier is to be used in place of the ships call sign, “D..D” (i.e. not the buoy identifier) with the addition of the letter Q as the first character: QA19nnnnn. Letter Q indicates in the TESAC message that the report is not from a ship; at the same time letter Q is not strictly speaking part of the WMO number. The seven-digits float identifier in TESAC was implemented for all floats deployed on and after 1 June 2001 (between December 1998 and June 2001, numbers allocated to Argo floats were of the form A19nnn). WMO numbers have to be obtained BEFORE deployment. When using BUFR, the letter Q is not being used as it is not part of the WMO number.

  • Marine animals: Marine animals equipped with observing instruments may distribute the geo-physical variable measures using BATHY, TESAC, BUFR, or CREX code forms. To avoid confusion with other types of marine observing stations, WMO numbers in the form 99nnnnn are being allocated. These numbers will be allocated as unique numbers as long as there are numbers available. When using BATHY or TESAC, the identifier is to be used in place of the ships call sign, “D..D” (i.e. not the buoy identifier) with the addition of the letter Q as the first character: Q99nnnnn. Letter Q indicates in the BATHY or TESAC message that the report is not from a ship; at the same time letter Q is not strictly speaking part of the WMO number. The seven-digits marine animal identifier in BATHY or TESAC was implemented in June 2008. WMO numbers have to be obtained BEFORE deployment. When using BUFR, the letter Q is not being used as it is not part of the WMO number.

(see also the WMO number page)

 
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