First claim-grade confidence check did not meet its target

Question

Do RefCal's published per-band confidence intervals contain independent reference values as often as intended across a claim-grade real-data set?

Did not hold Superseded How stages are defined

This result has been superseded by Confidence coverage on a like-for-like surface basis (22 Sept 2026). It stays published as part of the record.

§ 01

The result

What we did

RefCal compared its published per-band confidence intervals with values then treated as RadCalNet surface reference measurements. The claim-grade subset contained 131 measurement rows across 121 independent site-days at all six available sites.

What we saw

On that basis, the intervals contained the reference value in 0.397 of cases, against a nominal 0.683. Later lineage work established that the comparison mixed surface reflectance with top-of-atmosphere reference values, so this number does not describe current surface-to-surface confidence performance.

What it means

This run failed on the basis used at the time and remains part of the dated record. It taught a more fundamental lesson than the original verdict: confidence coverage is not interpretable when the product and reference describe different measurement levels. The corrected surface-to-surface result now carries the current evidence.

§ 02

Conditions and limits

This is the historical verdict produced when SIAC surface reflectance was compared with a RadCalNet value later found to be top-of-atmosphere reflectance. It is not the current confidence verdict.
The coverage factor was declared as one because RadCalNet does not publish it; the register therefore keeps the overall verdict qualified even though the measured shortfall is large.
This is an outcome-level result. It states that confidence is provided per band but does not describe how RefCal produces or updates those intervals.
The result remains visible because it was the first claim-grade run and shows why matching the reference basis matters. A corrected surface-to-surface result supersedes it.

§ 03

Data and credits

RadCalNet RadCalNet reference measurements, with citation to Bouvet et al. 2019, Remote Sensing 11(20), 2401.
Copernicus Sentinel-2 Contains modified Copernicus Sentinel data 2024-2025.

§ 04

Areas of work

P06 Confidence that means what it says

§ Contact

Questions about this result?

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