WORLD METEOROLOGICAL ORGANIZATION TCM-VI/Doc. 4.5 ______(8.IX.2009) ______SIXTH TROPICAL CYCLONE RSMCs/TCWCs TECHNICAL COORDINATION MEETING ITEM 4.5 BRISBANE, AUSTRALIA

2 TO 5 NOVEMBER 2009 ENGLISH ONLY

Tropical Cyclone Advisory for International Civil Aviation and Coordination with WAFCs

(SPECIFIC NEEDS OF INTERNATIONAL AIR NAVIGATION)

(Submitted by the International Civil Aviation Organization)

This paper presents information about the implementation of, and proposed changes to, the tropical cyclone advisories issued by tropical cyclone advisory centres for international air navigation.

Action proposed

a) To fully implement the provisions related to the content, format and dissemination of tropical cyclone advisories contained in ICAO Annex 3/WMO Technical Regulations [C.3.1];

b) to take note of the proposed amendments to Annex 3/Technical Regulations [C.3.1] to be applicable on 7 November 2010;

c) to agree that, as an intermediate solution, the PNG chart form be used for the tropical cyclone advisories in graphical format; and

d) to note the longer term plans concerning the migration to the use of XML for tropical cyclone advisories in graphical format.

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. IMPLEMENTATION OF TROPICAL CYCLONE ADVISORIES FOR INTERNATIONAL AIR NAVIGATION

1.1 Tropical cyclone (TC) advisories issued by tropical cyclone advisory centres (TCAC) play an important role for the safety and efficiency of international air navigation. Therefore, their full implementation in accordance with the provisions contained in ICAO Annex 3/WMO Technical Regulations [C.3.1] is of prime importance to ICAO. This includes the issuance, correct formatting and dissemination of these advisories.

1.2 According to the information available from ICAO Regional Offices, the implementation of the issuance of these advisories in alphanumeric format by all the TCAC is satisfactory, and no specific action is required.

1.3 With regard to the format, a detailed study by the aviation users indicate that it is, by and large, in accordance with international standards; only the following issues should be brought to the attention of TCAC:

a) General: only abbreviations included in the template in Table A2-2 in Appendix 2 to Annex 3/Technical Regulations [C.3.1] should be used;

b) General: TC should be self-contained and no reference to information included in the previous advisory should be made;

c) Name of tropical cyclone (Item TC): this should refer only to the name of the tropical cyclone, not to the category of the system (e.g. terms such as “tropical depression” should not be included), nor to its number;

d) Advisory number (Item NR): The number should be in two digits, i.e. “01” for the first advisory of each cyclone. followed by “02” for the second advisory etc.. The number should not be related to the number of tropical cyclones observed during each cyclone season;

e) Direction and speed of movement (Item MOV): This item should provide the movement using sixteen compass points, not degrees; and

f) Forecast of centre position. The inclusion of the 6-hour forecast (as stipulated in Amendment 74) for the TC centre position is essential since increasingly, these advisories are used not only in addition to, but also in lieu of, SIGMET.

1.4 It is important that TC advisories reach the uplink stations of the ICAO satellite broadcasts in the United Kingdom and United States. According to the information made available to ICAO by the United Kingdom, advisories have been received from most TCAC.

2. AMENDMENT 75 TO ICAO ANNEX 3/WMO TECHNICAL REGULATIONS [C.3.1]

2.1 An amendment related to the provisions governing the TC advisories has been developed with the assistance of the International Airways Volcano Watch Operations Group (IAVWOPSG) and Meteorological Information Data Link Study Group (METLINKSG), based on 3 long-standing requirements by airline users (through IATA). This draft amendment includes the following changes:

g) additions of a specification for tropical cyclone advisory information in graphical format to be added in Appendix 1 to Annex 3 (attached to this paper for information); and

h) change of the identification of unnamed cyclones; the term “NIL” will be replaced by “NN” (since the term “NIL” was considered misleading by some users).

2.2 The meeting will note that the TC advisories in graphical format must include all the information included in the existing alphanumeric tropical cyclone advisory, together with areas affected by gale-force surface winds and frequent cumulonimbus clouds. This information, if provided in binary format, is expected to be in the BUFR code form although no BUFR code tables have yet been developed for such advisories.

2.3 The amendment proposal has been subject to consultation with all ICAO Contracting/WMO Member States and no adverse comments were expressed as far as the issues related to TCs are concerned. Therefore, it may be expected that the ICAO Council will adopt the amendment without changes in March 2010. The proposed applicability date will be 18 November 2010.

3. IMPLEMENTATION OF GRAPHICAL ADVISORIES AS PART OF AMENDMENT 75

3.1 Concerning the implementation of graphical TC advisories, it appears that the additional information required for inclusion in graphical TC advisories by international aviation (i.e. the horizontal extent of gale-force winds and frequent CB clouds) is readily available at all WMO TC RSMCs/ICAO TCACs and should therefore be straight-forward to implement. Meanwhile, the procedures related to the encoding of the graphical advisories have not been established and need to be resolved as a matter of urgency.

3.2 As mentioned in Section 2) above, Amendment 75 recommends that the use of the BUFR code form for graphical TC advisories. Since the aeronautical MET codes are the prerogative of WMO, in accordance with the Working Arrangements between the International Civil Aviation Organization and the World Meteorological Organization (Doc 7475), the reference to the BUFR code form was introduced some years ago based on advice from WMO. However, no BUFR code tables exist currently that could be applied to these advisories.

3.3 However, the meeting may be aware of the fact, that the use of the BUFR code form for aeronautical operational meteorological (OPMET) messages (e.g. METAR/SPECI and TAF) has been questioned at a number of ICAO and WMO meetings. Therefore, the migration of OPMET messages to the BUFR code form was suspended by the ICAO Air Navigation Commission; while the CBS/CAeM Expert Team on OPMET Data Representation (ET-ODR) has being addressing the possibility of using XML code form for OPMET data. The first results of a pilot project undertaken in July 2009 by the ET-ODR involving XML are promising. Under these circumstances, it appears that it is highly likely that in the medium and long term, most aeronautical MET data will migrate to the use of XML, including the tropical cyclone advisories. Such a solution would be in line with the plans by Eurocontrol and United States Federal 4 Aviation Administration (FAA) contained in their SESAR/NexGen Programmes which will pave the way for a major aviation upgrade compatible with the requirements of the 21st century. The introduction of XML is a major change and will take place over a long period of time (i.e. over the next decade). Therefore, it would be unrealistic to use XML for graphical TC advisories as of 2010. It would also be unwise to develop BUFR code tables for graphical TC advisories (which would require some time and a lot of resources) knowing that it would be a solution of a temporary nature.

3.4 In view of the above, as an intermediate solution, it is suggested that the TCAC should consider using the portable network graphic (PNG) chart form for graphical TC advisories. The PNG chart form is based on off-the-shelf decoding software (rendering it cost effective both for TCAC and users of the TC advisories in States). This software is already used for ICAO world area forecast system significant weather forecasts (as a back-up) and volcanic ash advisories issued within the ICAO international airways volcano watch (IAVW), with positive feedback.

3.5 It may be noted that the ICAO aeronautical fixed telecommunication network (AFTN) cannot be used to transmit any PNG-coded data; however, the introduction of enabling clauses allowing the use of the Internet as part of Amendment 75 will resolve this problem.

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