Service Name

Quantitative Volcanic Ash information service

Service Abstract

Quantitative Volcanic Ash is a new Service defined internationally in ICAO provisions, which provides greater detail than existing advisory information (VAA) of volcanic ash in the atmosphere, including probabilities of ash concentration thresholds over space and time. This has been developed to provide flight operators with information to help identify airspace where ash concentration thresholds that do not pose a safety concern, may still be utilised to improve route efficiency.

There are two European designated Volcanic Ash Advisory Centre’s – VAAC London and VACC Toulouse which will provide QVA information services in the event of any significant volcanic activity impacting aviation within their respective geographical areas of responsibility.

Common Service Definition

The service definition for the Quantitative Volcanic Ash Information Service is currently under development (see the Quantitative Volcanic Ash Information Subscription and Request Service). The work is a coordinated effort by the two European VAACs. It is expected that this will then be used to ensure harmonisation between the nine VAACs around the globe.

Service Implementation Status

QVA information will be available as SWIM service(s) in Europe in late 2024.

Service Information

QVA information provides users with a high-resolution four-dimensional representation of a volcanic ash cloud, providing a more realistic depiction of the ash cloud.

Grid point forecasts of quantitative volcanic ash concentration shall be in a regular grid with a horizontal resolution of 0.25° of latitude and longitude and vertical height ranges:

relative frequency of exceedance probabilities for the volcanic ash concentration thresholds of 10, 5, 2 and 0.2 mg/m3
Forecasts of QVA concentration information shall be valid for fixed times of 0, 3, 6, 9, 12, 15, 18, 21 and 24 hours after the time (0000, 0600, 1200 and 1800 UTC) of the synoptic data on which the forecasts were based.
Updated forecasts of quantitative volcanic ash concentration information shall be issued as necessary but at least every six hours until the volcanic ash “cloud” is no longer considered to be significant.

Gridded data will be provided in a GRIB file format
Additionally, QVA concentration information shall be made available as objects in IWXXM form for the very high, high, medium and low quantitative volcanic ash concentration ranges:

QVA information offers operators the opportunity to move away from traditional discernible/visible ash criteria and instead use certified engine susceptibility for flight route planning and inflight replanning. Visible ash is what an observer or flight crew member sees with their eyes. Discernible ash is what a satellite or other remote sensing instrument detects. Discernible ash from satellites has been used by the VAACs to define the observed area in the volcanic ash advisories (VAA) in both text and graphic form (VAG) over the past two decades.

QVA information will likely have its greatest utility with ash cloud events that have a widely dispersed ash cloud with mostly lower levels of ash concentration.

Service Provision

Service Provider Organization

There are two European designated Volcanic Ash Advisory Centre’s – VAAC London and VACC Toulouse which will provide QVA information for their respective areas of responsibility.

Data Origination

The core observational information used to produce the QVA information services, comes from State Volcano Observatories responsible for the areas where the eruption occurred. Other types of observation (such as satellite imagery, LIDAR and air samples) are also utilised by the VAACs as appropriate and as available. These observations of volcanic ash and its source information, are used in conjunction with the dispersion modelling utilised by the designed VAAC to create the QVA information service for aviation.

Provision Architecture

The users of QVA information service(s) will obtain it from either of the two European VAAC (Toulouse or London) depending upon the area(s) impacted by ash.

Service Consumption

Service Consumer Organization

QVA will be used by operators and flight crew members (and flight planning providers)

Area control centres or a flight information centres will use QVA information

Network manager and EACCC will use QVA information

MET providers, including MWO’s and WAFC

Volcanic Ash Advisory Centres (VAACs)

Consumer Usage

The QVA information service(s) are designed to provide situational awareness of volcanic ash in the atmosphere which may have implications for the safety of aircraft in flight.

Pilots will use QVA information for flight planning purposes to avoid hazardous environmental conditions.
Flight operators will use QVA information to develop safety cases for any planned activities in affected airspace. Operators with approval and procedures/practices, e.g., maintenance for planned flight into select thresholds of ash concentration, will be able to use QVA information to fly more efficient routes in accordance with their safety management program. Probabilistic QVA information is intended for use in operator’s flight planning and decision support systems. Operators will use probabilistic QVA information in conjunction with their safety management program to optimise airspace and plan more efficient routes during significant volcanic ash cloud events.
Air Traffic providers and network manager will use QVA information to anticipate capacity and demand associate with rerouting of aircraft avoiding particular ash concentration thresholds. They also issue the appropriate ASHTAM which will be based on QVA information, as well as VONA and VAAs.
MET providers use the information for inclusion in other dependant MET information services, such as SIGWX charts and SIGMETs.