To automate collection, checks, calculation and publication while keeping a hard boundary between the authoritative source and non-operational simulation.
3 · What it produces
Official VONA relay and educational scenario remain visually and logically separate.
When a new positive VONA appears, the workflow blocks the educational simulation and can relay the official notice through independent IT/EN root posts. Under CLEAR status, the pipeline can produce four educational cards covering trajectories, proximity, quality and limitations.
4 · How it works
From authoritative source to the gate, then to the appropriate model.
1INGV VONA and source verification
2Open-Meteo 700/500 hPa
3FIRMS + GIBS as context
412h kinematic advection
5Haversine + asset alignment
6Policy gate + dedup + Bluesky
The trajectory moves a point hourly using wind speed and direction at the selected pressure level. Alignment is the minimum Haversine distance to simplified transport geometries; its score is heuristic, not a probability.
5 · Data used
| Source | Information | Use in calculation | Control |
|---|---|---|---|
| INGV VONA | official bulletin and POSITIVE/CLEAR/UNKNOWN status | source gate and event relay | fail closed if the authoritative source cannot be verified |
| Open-Meteo | forecast wind at 700 and 500 hPa | hourly vectors for the 12h trajectory | NaN/completeness checks and live-data validity |
| NASA FIRMS | thermal anomalies and FRP | optional context | never treated as proof of ash |
| NASA GIBS VIIRS | true colour + thermal anomalies | visual context | graceful fallback; not ash evidence |
| Transport assets | simplified airports, roads, rail and ports | minimum distance and alignment band | geometry screening, not plume width or impact |
Advection and distance
Hourly 12h step; wind vector converted to Δlat/Δlon; Haversine distance and broad alignment thresholds.
Isolation Forest on winds
Isolation Forest provides only a TYPICAL/UNUSUAL percentile for available wind context: it does not detect ash or predict eruptions.
Fail-closed and idempotent
GitHub Actions orchestrates scheduled/manual runs; positive or unknown official state blocks simulation. Run keys and monitor state prevent intentional duplicates.
Not a warning system
No estimate of concentration, deposition, visibility, engine risk, closure or service disruption.
Workflow technical dossier
Methods, validation and implementation stack.
Runtime and packages
- pandas and NumPy for data and calculations.
- scikit-learn / IsolationForest only for wind anomaly context.
- Matplotlib and Pillow for cards; BeautifulSoup and pypdf for controlled parsing.
- pydantic and requests for config/HTTP; GitHub Actions and AT Protocol/XRPC for orchestration/publication.
Geometry
- Trajectories at about 3 km (700 hPa) and 5.6 km (500 hPa) in the current configuration.
- Asset polylines are densified before minimum-distance calculation.
- ELEVATED/MODERATE/LOW/NO MATERIAL ALIGNMENT bands are distance-based heuristics.
Governance
- Mandatory disclosure on cards/captions and traced provenance.
- FIRMS/GIBS are thermal/visual context, never ash evidence.
- VONA monitor every three hours plus fallback within production workflow.
Publishing
- Independent IT/EN root posts and up to four images per post.
- Event relay is deduplicated and shares concurrency with weekly production.
See recent outputs
The Publications page can show multiple images from the same post or preview, with gallery navigation.