RA 2021_01

--- Draft (First created on 21 Jul 2021. To be reviewed by TT-AvData members ---

Proposed amendment (Amendment 81) to Annex 3/PANS-MET approved by ICAO METP

The proposed amendments were discussed and approved at METP/5 (Jun 2021) for ANC's consideration.

Details of the proposed changes

Proposal I: Provision of Volcano Observatory Notice for Aviation (VONA) by State Volcano Observatories (SVO)

See [Issue 305](https://github.com/wmo-im/iwxxm/issues/305)

1. Relevant discussions at METP/5:

   • (Report to Agenda Item 7. Para. 7.1.5) The meeting discussed the merits of the elevation of the VONA in abbreviated plain language and/or in IWXXM... However, the meeting noted the contrary concerns relating to the limited ability of users or user systems to utilise IWXXM information and therefore a staged approach from abbreviated plain language (also referred to as TAC) to IWXXM should be adopted.

2. See the extracted Template for Volcano Observatory Notice to Aviation (VONA) from the proposed text in working paper METP/5-WP/4102.

3. Other requirements mentioned in METP/5-WP/4102 include:

   • (PANS-MET/Para. 6.1.6) VONA shall be in abbreviated plain language, using approved ICAO abbreviations and numerical values of self-explanatory nature, and shall be in accordance with the template shown in Appendix 7, Table A7-1. When no approved ICAO abbreviations are available, English plain language text, kept to a minimum, shall be used to describe elements for which the template allows the use of free text.

   • (PANS-MET/Para 6.1.8) Only the following aviation colour codes shall be reported in the VONA:

     1. GREEN — the volcano is in a normal, non-eruptive state; or, volcanic activity is considered to have ceased, and the volcano has reverted to its normal, non-eruptive state;
     2. YELLOW — the volcano is experiencing signs of elevated unrest above known background levels; or, volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase;
     3. ORANGE — the volcano is exhibiting heightened unrest with increased likelihood of an eruption; or a volcanic eruption is underway but with no or minor volcanic ash emission;
     4. RED — a volcanic eruption is expected to be imminent with significant emission of volcanic ash into the atmosphere likely; or, a volcanic eruption is underway with significant emission of volcanic ash into the atmosphere; and
     5. UNASSIGNED — there is insufficient information available to assess the current status of the volcano or volcanic activity.

     Note.— The aviation colour code applies only to current volcanic activity associated with a volcano and does not apply to re-suspended volcanic ash

   • (PANS-MET/Para. 6.1.9) ... Further information on VONA is included in the Handbook on the International Airways Volcano Watch (IAVW) - Operational Procedures and Contact List (Doc 9766).

   Example(s)

   See Example A7-1.

   Analysis

   TBI

Proposal II: Introduction of information on Quantitative Volcanic Ash (QVA) clouds

1. Relevant discussion at METP/5:

   • (METP/5 - WP/2402, Appendix A) Final Functional and Performance Requirements for QVA Information at IOC - ... Data to be provided in gridded format, for example as GRIB2 and/or NetCDF. This will consist of 3D forecast concentration data, not specific threshold data. Volcanic ash objects be supplied in IWXXM form (objects will be defined by the quantitative ash ranges of very high, high, medium and low)
   • (METP/5 - WP/2402, Appendix C, PANS-MET, Chapter 5) En-route Meteorological Forecast Information:
     • Para. 5.3.6: In addition to 5.3.5 quantitative volcanic ash concentration information shall be made available as objects in IWXXM form for the very high, high, medium and low quantitative volcanic ash concentration ranges given in Appendix 9, Table A9-2.

2. See the extracted Technical Specifications Related To Forecasts of Quantitative Volcanic Ash Information in working paper METP/5-WP/2402.

   Example(s)

   Not available.

   Analysis

   TBI

Proposal III: Changes to the template for advisory information on volcanic ash (VAA), consequential to the introduction of VONA and other revisions

1. Relevant discussions at METP/5:

   • (Report to Agenda Item 7. Para. 7.1.7) The meeting further noted with the elevation of the VONA to a recommended practice, the work stream agreed to remove the aviation colour code from the VAA template, to reduce the likelihood of conflicting information and any confusion when an aviation colour code is not able to be provided within the VAA, due to the volcano not being able to be monitored adequately...
   • (Report to Agenda Item 7. Para. 7.1.9) The meeting was further informed that the work stream discussed improvement of VAA template to more clearly indicate available information in an initial VAA (issued in the initial stages of a new eruption, when dispersion model information may not be available) and re-broadcast VAA (refers to another VAAC’s VAA that describes volcanic ash affecting area of responsibilities of the both VAACs)...

2. See the extracted Template for advisory information on volcanic ash from the proposed text in working paper METP/5-WP/4102.

3. Other changes mentioned in METP/5-WP/4102 include:

   • Renaming the VAA element ‘Summit Elevation’ to ‘Source Elevation’ to better describe the element contents (as the vent emitting volcanic ash may not be at the summit of the volcano), along with new information under Detailed Content to describe its use.
   • Addition of a mandatory height reference for the Source Elevation – AMSL or BLW MSL, plus inclusion of footnote to indicate latter is to be used only for undersea volcanoes (as there are no volcano vents inland that are below AMSL included in the Smithsonian Global Volcanism Program Holocene volcano list).
   • Removal of the option ‘SFC’ for the Source Elevation, as the elevation of a volcanic ash source must be described in reference to MSL for use by VAAC dispersion models, or otherwise indicated as UNKNOWN. For re-suspended volcanic ash, the Detailed Content notes indicate the average height of volcanic ash field is to be used.
   • Inclusion of NOT PROVIDED in the Time of observation of ash and Observed ash cloud element templates, to facilitate a VAAC issuing a re-broadcast VAA that simply refers to the neighbouring VAAC’s VAA that describes the area of volcanic ash that affects both VAAC’s areas of responsibility – and does not have to re-produce elements of that VAA.
   • Inclusion of NOT AVBL in the Observed ash cloud element template, to facilitate a VAAC issuing an initial VAA that simply informs users an eruption has occurred and more information will follow soon, as OBS or FCST volcanic ash may not yet be available.
   • Removal of an example for the Observed ash cloud element which is no longer permissible (correcting an error).
   • Minor changes including editorial changes to the footnote for using TEST and EXER, adding a footnote to clarify the limit to the coordinates and the projection of straight lines when sending in abbreviated plain language (sometimes referred to as TAC), updating the VAA example to remove the aviation colour code, and updating example date-time groups.

   Example(s)

   See Example A7-2.

   Analysis

   TBI

Proposal IV: Changes to space weather information

1. Relevant discussion at METP/5:

   • (METP/5 - WP/2302, Appendix C, PANS-MET, Appendix 7) Rationale for the proposed revisions to Annex 3 and PANS-MET:
     • Moved the “Intensity” from the “Effect” line to the “Observed” and “Forecast” lines, which allows for the intensity to change within an advisory as well as allows for multiple intensities, thus reduces the number of advisories in effect at one time.
     • Allow for an updated advisory to replace up to four existing advisories.
     • Added “NIGHTSIDE” and renamed “DAYLIGHT SIDE” to “DAY SIDE”
     • Updated the template and examples in the Table.
     • Removed the “minutes” from latitude and longitude since this accuracy is beyond the state of the science.
     • Editorial changes to footnote 1 for TEST and EXER.
     • Clarified that altitude information only applies to radiation events.
     • Clarified that the end point of a polygon is a repeat of the start point.
     • With the agreement that MET products in IWXXM form are not constrained to limits of coordinates, made note that advisories disseminated in abbreviated plain language should keep coordinates to a minimum of seven. This same note has been added to other similar MET products.

2. See the extracted Proposed amendments to the restructured Annex 3 in working paper METP/5-WP/2302.

   Example(s)

   See Examples A7-3 to A7-5.

   Analysis

   TBI

Proposal V: Relaxation of TAC constraints on IWXXM

1. Relevant discussion at METP/5:

   • (Report to Agenda Item 6. Para. 6.15) The Panel noted that the WG-MIE developed the proposed changes ..., including ... a few changes in METAR/SPECI that removes constraints related to the number of RVR and inclusion of tenths of temperature and dew point, ... It was noted that the removal of the IWXXM constraints does not form a new requirement but is intended to create the capacity, to enable States that wish to do so, to provide this additional information in IWXXM form.

2. See the extracted Proposed amendments to the restructured Annex 3 in working paper METP/5-WP/3301.

   Example(s)

   Not applicable.

   Analysis

   TBI