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WAFSOPSG/3-WP/4/
International Civil Aviation Organization
WORKING PAPER / WAFSOPSG/3-WP/4
26/7/06
WORLD AREA FORECAST SYSTEM OPERATIONS GROUP (WAFSOPSG)
THIRD MEETING
Paris, France, 26 to 29 September 2006
Agenda Item / 5: / Operation of the WAFS5.1: / WAFS management report WAFS management report
5.2: / Back-up procedures at the WAFCs
5.3: / Assessment of WAFS output performance indicators
5.4: / Review of the ISCS User Guide
5.5: / Availability of WAFS forecasts in chart form beyond 30 November 2006
5.6: / Dissemination of the analysis of the global forecasts to WAFS User States
ISSUES RELATED TO THE OPERATION OF WAFS
(Presented by the Secretary)
SUMMARYThis paper addresses issued related to the operation of the world area forecast system (WAFS).
1. INTRODUCTION
1.1 The group will be aware that, in accordance with its terms of reference, the WAFSOPSG is expected to provide advice and guidance to the WAFS Provider States concerning the operation of the WAFS, including the satellite broadcasts (ISCS and SADIS), and its effectiveness in meeting current global and, where appropriate, regional operational requirements.
1.2 Under this agenda item, the group is expected to deal with the tasks in the work programme related to the operation of WAFS, and propose mechanisms in order to advise and guide the WAFS Provider States concerning the operation of the WAFS. Tasks of an operational nature emanating from planning and implementation regional group (PIRG) meetings should also be addressed.
2. WAFS management report
2.1 The group will recall that it requested the WAFS Provider States to prepare a concise management report (Conclusion 1/3 refers). The group will note that the WAFS management report has been prepared by the WAFS Provider State and is contained in WP/8. The group is invited to review the management report, note its content and agree that the scope of issues covered meets the requirements expressed by the group in Conclusion 1/3.
3. Back-up procedures at the WAFCs
3.1 The group will recall that it concurred at its second meeting that World Area Forecast Centre (WAFC) London should continue to provide a back-up data service to the ISCS uplink hub and maintain reception capability of the ISCS broadcast; and establish a bulletin monitoring facility that could be used to verify, on a real-time basis, the operation of the ISCS broadcast (Conclusion 2/7 refers). With regard to the establishment of a bulletin monitoring facility, it was considered appropriate in view of the responsibilities of WAFC London to provide an effective back-up service to the ISCS broadcast, when necessary.
3.2 The WAFC Provider States have re-assessed the need by WAFC London to establish a bulletin monitoring facility for supporting a back-up data service to the ISCS. WAFC Washington has indicated that they have no requirement for this service since they already monitor the ISCS broadcast at two or more sites. Furthermore, WAFC London has no funding to maintain such a facility. The WAFC Provider States therefore recommend that no bulletin monitoring facility to support the ISCS broadcast should be established. The group is invited to endorse this point of view and to formulate the decision as in included in WP/9.
4. Assessment of WAFS output performance indicators
4.1 It will be recalled that the WAFSOPSG/2 Meeting formulated Conclusion 2/11 calling for the WAFC London Provider State, in coordination with the WAFC Washington Provider State, to implement, on a trial basis, the following performance indicators:
1) root mean square (RMS) wind error for 250 hPa (FL 340) at T+24 for
— North Atlantic (N40W075-N70W090-N70E015-N40E000)
— North Pacific (N30E120-N75E120-N75W120-N30W120)
— Asia (N25E060-N65E060-N65E145-N25E145)
— Northern Hemisphere (N30-N90)
— Tropics (N30-S30)
— Southern Hemisphere (S30-S90)
2) RMS temperature error for 250 hPa (FL 340) at T+24 for:
— North Atlantic (N40W075-N70W090-N70E015-N40E000)
— North Pacific (N30E120-N75E120-N75W120-N30W120)
— Asia (N25E060-N65E060-N65E145-N25E145)
— Northern Hemisphere (N30-N90)
— Tropics (N30-S30)
— Southern Hemisphere (S30-S90); and
3) availability (in percentage) of BUFR and GRIB data at the WAFCs.
The group will be pleased to note that for these trials, the WAFS Provider States have implemented the provision of the above statistics for the regions listed above. The statistics is provided on a quarterly basis using monthly statistics and is included in two separate websites which can be accessed through the WAFSOPSG website. The timeliness of transmission for selected GRIB and BUFR bulletins is also made available.
4.2 The group is invited to review the output performance indicators used during these trials by WAFS Provider States (WP/10 refers). It may wish to agree that the indicators meet the operational requirements and should therefore be implemented on a permanent basis. In this regard, the group may wish to formulate the conclusion as included in WP/10.
5. Review of the ISCS User Guide
5.1 The group will be aware that it agreed that the WAFC Washington Provider State should develop an International satellite communications system (ISCS) User Guide with a scope similar to that covered by the SADIS User Guide (SUG) (Conclusion 2/5 refers) It was also agreed that there was no need to develop Annex 1 (entitled “OPMET information required from aerodromes to be included in the ISCS broadcast”), nor Annex 4 (entitled “WAFS forecasts disseminated on the ISCS”).
5.2 The group will be pleased to note that the WAFC Washington Provider State has developed the first edition of draft ISCS User Guide. It may be noted that this version of the ISCS User Guide consists of five chapters, five appendices and four Annexes. The chapters deal, inter alia, with the management of the system, authorization to access ISCS, an overview of data provided over the broadcast and the basic requirements for data processing. Furthermore, a list of points of contact in the United States National Oceanic and Atmospheric Administration (NOAA) for ISCS is provided in order to obtain assistance should the user encounter problems with the broadcast.
5.3 The group is expected to review and amend the draft included in WP/11, as necessary. With regard to Annexes, the group will find out that Annexes 2 and 3 to the ISCS User Guide relating to the actual OPMET content of the ISCS broadcast are still under development and will be made available in due course by the WAFC Washington Provider State. It may be noted that Annex 1 stating the international requirements for OPMET data is based on formal regional air navigation agreements (as far as OPMET data from AOP aerodromes is concerned) and bilateral agreements between ICAO and the State concerned (as far as OPMET data from non-AOP aerodromes is concerned). Likewise, Annex 4 listing the WAFS forecasts included in the satellite broadcast reflects the international requirements. Therefore Annexes 1 and 4 in the ISCS User Guide should be identical to the files (and data bases) being maintained by the ICAO Secretariat and included in the SUG (as an URL address). The group may wish to reiterate its earlier position that there is no need to reproduce Annexes 1 and 4 for the ISCS User Guide and conclude that only the headings of Annexes 1 and 4, together with the appropriate URL address to the relevant ICAO website, should be included in the ISCS User Guide.
5.4 It may be noted that the WAFC Washington Provider State plans to make the ISCS User Guide available through its file server to all States and users under the ISCS 1/2 broadcast area. The group may wish to exchange views on the desirability of the availability of the ISCS User Guide through the appropriate ICAO websites, similar to the SUG. It is invited to formulate the decision as included in WP/11.
6. Availability of WAFS forecasts in chart form beyond 30 November 2006
6.1 It will be recalled that the WAFSOPSG/2 Meeting formulated two conclusions related to the availability of SIGWX forecasts in chart form beyond 1 July 2005, i.e. Conclusions 2/12 and 2/13. The first one called for WAFS Provider States to extend the provision of SIGWX forecasts in T4 chart form beyond 1 July 2005, for a limited period of time, until 30 November 2006 and for the ICAO Regional offices to carry out a survey in May 2006 to verify the implementation of BUFR-coded SIGWX forecasts by States and for the Secretariat to present the results of this consultation for consideration and future action by the WAFSOPSG/3 Meeting. In parallel, Conclusion 2/13 invited the WAFS Provider States to provide, on a trial basis, WAFS SIGWX forecasts in chart form for the fixed ICAO areas of coverage using the portable network graphics (PNG) format; place these charts on the SADIS FTP server by 1 July 2005; and report back to the WAFSOPSG/3 Meeting to facilitate the group to assess the desirability of continuing the provision of WAFS SIGWX forecasts in the PNG format.
6.2 In response to action called for by Conclusion 2/12, the group will be pleased to note that the WAFCs have continued to provide the SIGWX forecasts in T.4 chart form. Moreover, the Secretariat has undertaken the survey on the implementation of BUFR-coded SIGWX forecasts by States through the Regional Offices. The results of the survey presented in the appendix to this paper indicate that currently some 60 per cent of States (out of 68 which have replied) are in a position to receive BUFR-coded SIGWX forecasts and that by the end of 2006, the percentage is expected to rise to 79. By the end of 2008, some 90 per cent of States which have replied indicate that they would be in a position to receive and decode the BUFR-coded SIGWX forecasts. The group may wish to concur that the survey clearly indicates that a vast majority of States which have replied have migrated, or have plans to migrate over the next two years, to the use of BUFR-coded SIGWX forecasts, in full accordance with Amendment73 to Annex 3 endorsed by the worldwide MET Divisional Meeting (2002) and adopted by the ICAO and WMO Councils. However, in view of the slower-than-expected pace of migration, it may be considered that the continued provision of SIGWX forecasts in a chart form would be highly desirable.
6.3 To be able to decide the way forward, the group is invited to consider, in parallel, the report prepared by the WAFS Provider State concerning the trials of the PNG-formatted SIGWX forecasts undertaken in response to Conclusion 2/13. The report indicates (WP/12 refers) that the issuance of the PNG-formatted SIGWX forecasts is currently a routine part of the WAFC production schedule and that the commercial providers of WAFS visualisation software have developed the capability to ingest these products and display them via commercial-off-the-shelf (COTS) applications. The availability of these functions has been included in the recent software review completed by the WAFC London Provider State which has also developed an application that enables the display of these products via a COTS application. This process has been used by the Agency for Air Navigation Safety in Africa and Madagascar (ASECNA) and has assisted them in gauging the usefulness of the PNG formatted charts which can be displayed directly from a web browser.
6.4 The group will note that based on these trials, a number of users, including ASECNA (WP/20 refers), have indicated their preference that the PNG-formatted SIGWX charts be maintained on the SADIS broadcast. No requirement for SIGWX forecasts in T4 chart form beyond 30 November 2006 has been expressed. The WAFS Provider States also consider that the availability of the PNG-formatted SIGWX charts on the WAFS broadcasts should be ensured. In addition to the lower-than-expected level of implementation of the use of BUFR-coded forecasts (currently at 60 per cent), this assessment by the WAFS Provider States is based on the risk of the use of non-compatible visualization software (currently less than 15 per cent of users rely on software which has not been assessed) and the inherent complexity of the BUFR code form which could render it unsuitable (and too costly) to some States and users.
6.5 The group will be aware that substantial efforts have been made over the past few years to introduce the BUFR-coded SIGWX forecasts within WAFS. These include extensive assessments of visualization software and convening of a series of ICAO/WMO regional seminars on the use of the BUFR code form within the WAFS. Furthermore, most States have spent financial resources to migrate to the use of the BUFR-coded SIGWX forecasts. Therefore, the group may wish to concur that it would not be appropriate to change the “roadmap” at this late stage; the use of the BUFR code form for SIGWX forecasts should remain the primary means of receiving SIGWX forecasts within WAFS. In view of the concerns expressed by some users and the WAFS Provider States, the group may wish nevertheless to agree that the PNG-formatted SIGWX forecasts should be provided as a back-up to the BUFR-coded forecasts until such a time that SIGWX forecasts be replaced by gridded products of turbulence, icing and convective clouds (Agenda Item 5 refers).
6.6 The group is invited to formulate the following conclusion:
Conclusion 3/... — Provision of WAFS SIGWX forecasts in chart form beyond 30 November 2006That,
a) the WAFS Provider States be invited to discontinue the provisions of WAFS SIGWX forecasts in T.4 chart form as of 1 December 2006; and
b) as a back up to the BUFR-coded SIGWX forecasts,
1) the WAFC London Provider State be invited to continue with the provision of the WAFS SIGWX forecasts in the PNG chart form on the SADIS broadcast; and
2) the WAFC Washington Provider State be invited to add the WAFS SIGWX forecasts in the PNG chart form to the ISCS broadcasts by 30 November 2006.
Note 1.— The provision of the PNG charts is expected to continue until the replacement of SIGWX forecasts by gridded products of icing, turbulence and convective clouds; and
Note 2.— Upper-air wind and temperature charts will continue to be provided exclusively in the GRIB code form.
7. Dissemination of the analysis of the global forecasts to WAFS User States
7.1 It may be noted that the CAR/SAM Regional Planning and Implementation Group (GREPECAS) formulated Conclusion 13/19 calling for the WAFSOPSG to consider the possibility for the WAFC Washington to disseminate the analysis of the Global Forecast System model run to user States concerned.