AMOSSG/5-SN No. 5

21/3/05

AERODROME METEOROLOGICAL OBSERVING SYSTEMS STUDY GROUP (AMOSSG)

FIFTH MEETING

Montreal, 11 to 14 April 2005

Agenda Item	8:	Migration to BUFR coded OPMET messages

OVERVIEW OF PROGRESS WITH RESPECT TO THE MIGRATION TO BUFR CODED OPMET MESSAGES

(Presented by the Secretary)

SUMMARY
A summary of progress made with respect to the migration to binary universal form for the representation of meteorological data (BUFR) coded OPMET messages is given together with an overview of outstanding tasks for consideration by the group.

1.	INTRODUCTION

1.1	This study note summarizes the tasks that are under review by the group that concern the migration to binary universal form for the representation of meteorological data (BUFR) coded OPMET messages, together with an indication of previous discussion and, in some cases, suggested future courses of action.

1.2	The attention of the group is drawn to the consideration of changes which will be necessary to the provisions of Annex 3 — Meteorological Service for International Air Navigation.

2.	DISCUSSION

2.1	Progress concerning the development of BUFR code tables

2.1.1	The group may wish to note that the World Meteorological Organization (WMO) Expert Team on Data Representation and Codes (ET (DR & C)), at its meeting in Kuala Lumpur, Malaysia, 21 to 26 June 2004, agreed upon the formulation of BUFR code tables for METAR/SPECI, TAF and SIGMET. The development of the BUFR code tables is being coordinated with ICAO through the attendance of the Secretariat at both of the above meetings.

2.2	Migration plan for the introduction of BUFR coded OPMET messages (ANC task 0101)

2.2.1	The group will recall that the MET Divisional Meeting (2002) formulated its Recommendation 2/5 that invited WMO to develop a migration plan concerning the use of table-driven codes forms for the dissemination of METAR/SPECI and TAF. It was noted by the group at the AMOSSG/4 Meeting that a plan had been endorsed by the WMO Congress which included a timetable specifying that table-driven codes could be used, by those States in a position to do so, in parallel with the alphanumeric codes from 2007 and that the fully operational use of table-driven codes was planned for 2015.

2.2.2	In order to cater for the use of table-driven codes, by States in a position to do so, from 2007 there is a need to amend Annex 3 accordingly. It is proposed that such use of the BUFR code for METAR, TAF and SIGMET should be in addition to the current requirement to use the traditional alphanumeric codes and would be carried out between States under appropriate bilateral agreements. The proposed amendment to Annex 3 is given in the Appendix A for consideration by the group as a part of draft Amendment 74.

2.2.3	The group may wish to note that the European Air Navigation Planning Group (EANPG) at its forty-fifth Meeting held in Paris, 1 to 3 December 2003 formulated the following Conclusion:

Conclusion 45/12 —	MIGRATION TO BUFR CODED OPMET MESSAGES

That, ICAO give guidance to achieve a uniform global approach to the implementation of binary universal form for the representation of meteorological data (BUFR) coded operational meteorological (OPMET) messages, including early advice of the likely time-frame for the development of the provisions necessary for air traffic services message handling service (ATSMHS) extended services to accommodate BUFR coded messages.

2.2.4	In order to accommodate the exchange of BUFR coded messages it will be necessary to implement a global communications infrastructure that is capable of handling digital data which is not possible with the current aeronautical fixed service (AFS). The planning for the global aeronautical telecommunication network (ATN) is carried out by the ICAO Aeronautical Communications Panel (ACP) who would take the responsibility of providing the guidance requested by the EANPG. The group may wish to consider the broad set of requirements for such guidance given in Appendix B that would be considered as a basic framework for use by the ACP. The suggested set of requirements has been coordinated with the communications, navigation, and surveillance (CNS) section within the Air Navigation Bureau (ANB) of ICAO.

2.2.5	The group may wish to note that the European Air Navigation Planning Group (EANPG) at its forty-sixth Meeting held in Paris, 30 November to 2 December 2004 formulated the following Conclusion:

Conclusion 46/18 —	CONVERSION SOFTWARE FOR BUFR CODED OPMET MESSAGES

That, ICAO, in coordination with the World Meteorological Organization (WMO), develop the necessary specifications to ensure that a consistent presentation format is provided for Traditional Alphanumeric Codes (TAC) and that the mapping between BUFR and TAC is complete and unambiguous.

2.2.6	The group may wish to agree that the templates provided in Annex 3 for METAR/SPECI (Appendix 3, Table A3-2), TAF (Appendix 5, Table A5-1) and SIGMET (Appendix 6, Table A6-1) provide a clear and unambiguous description of the requirements for the alphanumeric representation of the respective messages. Furthermore, in order to ensure that the mapping from the BUFR code tables produced by WMO to the alphanumeric codes is unambiguous the group may wish to agree that the matter should be raised by the Secretary at the next meeting of the WMO ET (DR & C).

3.	ACTION BY THE GROUP

3.1	The group is invited to:

a)	consider the proposed amendment to Annex 3 contained in the Appendix A for inclusion as a part of draft Amendment 74;

b)	endorse the outline of guidance in Appendix B for a global plan for the implementation of the migration to the use of BUFR coded OPMET messages for use by the Aeronautical Communications Panel (ACP);

c)	agree that the templates provided in Annex 3 for METAR/SPECI (Appendix 3, Table A3-2), TAF (Appendix 5, Table A5-1) and SIGMET (Appendix 6, Table A6-1) provide a clear and unambiguous description of the requirements for the alphanumeric representation of the respective messages; and

d)	agree that the Secretary should raise the issue of ensuring an unambiguous mapping of the WMO BUFR code tables to the alphanumeric codes for METAR/SPECI, TAF and SIGMET at the next meeting of the WMO ET (DR & C).

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