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IAVWOPSG/4-WP/32
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International Civil Aviation Organization
WORKING PAPER / IAVWOPSG/4-WP/32
8/7/08

INTERNATIONAL AIRWAYS VOLCANO WATCH OPERATIONS GROUP (IAVWOPSG)

FOURTH MEETING

Paris, France, 15 to 19 September 2008

Agenda Item / 5: / Operation of the IAVWOPSG
5.2: / Improvement of the format and content of all volcanic ash related messages

DEFINITION OF THE TERM “OBSERVATION”

(Presented by Canada and the Secretary)

SUMMARY
This paper recommends that the definition of “OBSERVATION’’ in element 12 of the template be wide enough to accommodate the following statement: “The volcanic ash advisory statement should include a forecast (elements 14 to 16) whenever the professional evaluation by the VAAC meteorologist leads him / her to conclude that ash is present in the atmosphere in an amount sufficient to be considered a threat to aviation”.

1.  INTRODUCTION

1.1  At the third meeting of the International Airways Volcano Watch Operations Group (IAVWOPSG/3), the group discussed some issues concerning the volcanic ash advisory statement message format. It was noted that there are apparent discrepancies in the definition used by VAACs as to what constitutes an “OBSERVATION”. It ranges from a narrow definition (only satellite detection for example) to a much wider one that includes any information that may help deduce the presence of ash in the atmosphere.

1.2  A need was therefore identified for further consideration on what constitutes an “observation” (element 12) and related clarifications for element 13 (observed or estimated ash cloud) and 14 to 16 (forecast) of the template for advisory message for volcanic ash (Table A2-1 in Annex 3 — Meteorological Service for International Air Navigation , included at the end of the present paper). The group felt that to address these issues, the development of guidance would be necessary and in this regard, formulated Conclusion 3/13.

2.  DISCUSSION

2.1  The definition of “observation” is important given that element 12 serves as the reference time to which the details in element 13 and the forecasts in element 14 to 16 (i.e. +6 HR, +12 HR and +18HR) are tied. The definition has a direct impact on whether or not a forecast will be included in the advisory. For example, there may be no forecast if the definition of element 12 is based only on detecting ash with satellites.

2.2  While examining what the guidance might include, it became apparent that a more fundamental discussion was first needed within the IAVWOPSG regarding the objective for including information on “TIME OF OBSERVATION OF ASH” in relationship to elements 13 to 16 of the template. Specifically, the group needs to consider and express its views on the following statement that we submit for its consideration:

The volcanic ash advisory statement should include a forecast (elements 14 to 16) whenever the professional evaluation by the VAAC meteorologist leads him / her to conclude that ash is present in the atmosphere in an amount sufficient to be considered a threat to aviation.

2.3  If the group agrees with the statement in paragraph 2.2:

2.3.1  Then the definition of ‘’OBSERVATION’’ in element 12 of the template must be large enough to accommodate what that statement implies, since the forecast times in elements 14 to 16 are tied to the time of observation.

2.3.2  While the more traditional sources of information for ‘’observation’’ are fairly straight forward to identify (i.e. pilot or ground observer report and satellite data), additional or new information sources are also available or in the process of being developed (infrasound for example) and need then to be considered if a wide definition is used for ‘’observation’’.

2.3.3  This would also be more in line with the addition of the option ‘’estimated ash cloud’’ in element 13 of the template in Amendment 74 to Annex 3 as a way to express that some of the information may not be ‘’observed’’ in the traditional sense of the word.

2.3.4  We propose that the following definition of ‘’observation’’ could serve as the basis for the guidance:

“In the context of element 12 of the advisory message for volcanic ash, OBSERVATION is defined as a source of information that is used to establish a reference date and time to which the 6, 12 and 18-hour forecasts are tied (elements 14 to 16). This includes, but is not limited to:

(*** specifics to be defined after discussion within IAVWOPSG***)

- AIREP

- Report from a ground observer

- Satellite data

- Seismic data

- Infrasound data”

2.3.5  On a related point, the note at the end of Section 4.5e (ACTION TO BE TAKEN BY VAACs IN THE EVENT OF A VOLCANIC ERUPTION) of the Handbook on the IAVW would then need to be reviewed:

e) continue to issue updated advisory information to MWOs, ACCs and airlines

concerned at least at 6-hour intervals, and preferably more frequently, until such

time as it is considered that the volcanic ash cloud is no longer identifiable from

satellite data, no further reports of volcanic ash are received from the area and

no further eruptions of the volcano are reported;

Note. ― If volcanic ash is not identifiable from satellite data and the VAAC has

reasonable doubts about the existence of volcanic ash in the atmosphere, it

should be indicated in the REMARKS section of the volcanic ash advisory.

2.4  If the group does not agree with the statement in paragraph 2.2:

2.4.1  A discussion is needed on the scope of what ‘’observation’’ means and what the guidance is expected to include.

3.  CONCLUSION

3.1  In light of the objectives of the IAVW and the discussion of section 2.3, the group may wish to agree that the group accept that a wide definition of ‘’observation’’ is needed for element 12 of the template.

Therefore the group may wish to formulate the following conclusion:

Conclusion 4/.. — Guidance material related to the definition of the term “observation”
That the Member from Canada in coordination with the Secretariat, develop guidance related to the definition of observation for inclusion in Doc9766, Handbook on the International Airways Volcano Watch (IAVW) — Operational Procedures and Contact List.

4.  ACTION BY THE IAVWOPSG

4.1  The IAVWOPSG is invited to:

a)  note the information in this paper; and

b)  decide on the draft conclusion proposed for the group’s consideration.

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A-3 / IAVWOPSG/4-WP/32
Appendix
IAVWOPSG/4-WP/32
Appendix

APPENDIX

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