Observation time answers when the sensor measured the signal
The observation time comes from the source product and represents when the satellite instrument measured the thermal signal. It is the most relevant time for the point itself. It does not say when a fire started, whether it continued after the overpass or when an authority learned about an incident.
ThermalGlobe uses UTC for comparison across countries and satellites. The detail panel can show the timestamp in a consistent form, while users should still account for the local time zone when comparing the observation with local reports.
Observed-through is a source watermark
For each required sensor product, the release records the newest observation successfully included. This observed-through watermark helps reveal whether one source is behind the others. It is a property of the collected data, not a guarantee that every expected observation up to that moment is present.
Separate watermarks matter because NOAA-20, NOAA-21 and MODIS follow different orbits and processing paths. ThermalGlobe does not merge those products into a false single sensor timeline.
Source check and last successful fetch are operational times
The source-check time records when ThermalGlobe attempted to evaluate required inputs. The last successful fetch records when a valid response for a product was accepted. A recent check can coexist with older observations when the satellite has not made a useful pass or the source contains no newer qualifying row.
If a fetch fails, the release can retain the previous verified data with an explicit stale state. This is safer than publishing an empty dataset that users might misread as an absence of fire activity.
Release time answers when ThermalGlobe published the bundle
The release time is generated only after validation, filtering, spatial partitioning and integrity checks succeed. It tells you when the current map bundle was produced. It does not change the observation time and must not be presented as “detected now.”
A frequent scheduled check improves the opportunity to pick up newly available source data, but it does not create a real-time service-level agreement. Network, source and processing delays remain possible.
A practical reading order
- First read the point’s observation time and age band.
- Then check which sensor product supplied it.
- Check that product’s source status and observed-through watermark.
- Finally read the ThermalGlobe release or data-checked time.
- For official status, leave the satellite map and consult the responsible authority.