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Banner image showing GLAMR instrumentation


The plot shows the current total uncertainty for GLAMR as established for the OCI measurement campaign. The total uncertainty includes terms for NIST traceability, repeatability, noise, sphere uniformity, fluorescence of the sphere and linearity of the radiometers.

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Uncertainty Budget

The foundation of the GLAMR uncertainty is the uncertainty in the NIST calibration of the GLAMR transfer radiometers, which are used to transfer the NIST absolute radiometric scale from the SIRCUS system to the GLAMR sphere monitor radiometers. This plot shows the current state of the NIST uncertainty for the calibration of the transfer radiometers.

Uncertainty Reports

The full NIST report for the latest calibrations (2021/2022) can be accessed here:

- 2021 Silicon LTD-11-104 radiometer

- 2021 IGA Det-8-IGA-107 radiometer

- 2022 IGA Det-8-IGA-109 radiometer

- 2021 XIGA L-1-XIGA-002 radiometer

The NIST reports for the earlier calibrations can be accessed here:

- 2017 Silicon LTD-11-104 radiometer

- 2017 IGA Det-8-IGA-107 radiometer

- 2017 XIGA L-1-XIGA-002 radiometer

- 2019 Silicon LTD-11-104 radiometer

- 2019 IGA Det-8-IGA-107 radiometer

- 2019 XIGA L-1-XIGA-002 radiometer